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1. 140 7 5 4 Treatment of abnormal data 141 7 6 Determination of accuracy and precision 142 7 6 1 Point measurement 142 7 6 2 DOAS 147 7 7 QA QC implemented by the NC 151 7 8 Training programs 152 8 Conclusions 154 iii List of contributors This manual was prepared by the Expert Group on Preparation of Technical Manual for Air Concentration Monitoring under Scientific Advisory Committee of EANET Expert Group member Chair Dr Duong Hong Son Vietnam Institute of Meteorology Hydrology and Environment Vietnam Prof Min Hu Peking University China Dr Masahide Aikawa National Institute for Environmental Studies Japan Mr Hajime Mikasa Alternatively contributed by Dr Hu Li Japan Environmental Technology Associations Japan Dr Akinori Takami National Institute for Environmental Studies Japan Prof Young Joon Kim Gwangju Institute of Science and Technology Republic of Korea Dr Kihong Park Gwangju Institute of Science and Technology Republic of Korea Mr Phunsak Th
2. Figure 4 4 Sampling arrangements for denuder sampling Norwegian Institute for Air Research 2001 A schematic description of the sampling equipment used in EMEP is shown in Fig 4 4 Norwegian Institute for Air Research 2001 It consists of a small insulated box with a fan for internal air circulation a heating unit to control a temperature up to 2 C 99 Manual for Air Concentration Monitoring above the ambient temperature a rack for mounting the denuder sampling trains and filter packs electromagnetic valves connecting the sampling trains to a manifold a leak proof pump which gives a sampling rate of 15 l min and a gas volume meter for recording of the sample volume The electromagnetic valves activating each of the sampling trains are operated by means of an electronic timer Denuder and filter pack sampling trains can also be activated and changed manually The number of sampling lines may be extended up to eight The sampling train consists of an air intake 2 annular denuders of the length 242 mm and one denuder of the length 120 mm The denuders are connected by special threaded connectors and capped with threaded caps when not in use A special connect is used to connect the denuder train to a 3 stage filter pack containing a PTFE aerosol filter a KOH impregnated filter and a citric or oxalic acid impregnated filter Annular denuder technique is technically demanding
3. 120 5 3 3 Lifetime of instruments 122 5 3 4 Overhaul 122 5 4 Field record 123 5 5 Maintenance record 123 5 6 Safety management 123 5 6 1 Management of high pressure gas cylinders 123 5 6 2 Disposal of chemicals solution waste and monitoring instruments 125 6 Data reporting and validation 126 6 1 Site specification 126 6 2 Compilation of raw monitoring data 126 6 3 Data validation 128 6 3 1 Statistical tests 128 6 3 2 Data completeness 129 6 3 3 Analytical precision 129 6 3 4 Data flags and invalid data 129 6 4 Submission of finalized data
4. 130 6 4 1 Information about sites sampling shipping laboratory operation 130 6 4 2 Analytical condition for filter pack samples 132 6 4 3 Measurement results and flags 132 6 5 Data storage 132 7 Quality Control and Quality Assurance 136 7 1 Fundamental matters 136 7 2 Data Quality Objectives DQOs 136 7 2 1 Detection limits and reporting limits for air concentration data 137 7 3 Monitoring site Site audit 137 7 3 1 Site selection 137 7 3 2 Documentation of conditions around sampling sites 138 7 3 3 Site performance audit 138 7 4 Field and laboratory operations 138 7 5 Data management 139 7 5 1 Routine data check 140 7 5 2 Confirmation of measured data 140 7 5 3 Data screening
5. 3 3 Meteorology 3 3 1 Objectives 3 3 2 Wind direction anemometer 73 3 3 3 Thermometer 76 3 3 4 Hygrometer 78 3 3 5 Actinometer 79 3 3 6 Rain gauge 81 4 Manual monitoring 84 4 1 Filter pack 84 4 1 1 Principle of using filter pack 84 4 1 2 Artifacts of filter pack 85 4 1 3 Specifications of filters 87 4 1 4 Sampling 88 4 1 5 Operation in laboratory 91 4 1 6 Determinations of concentrations and data reporting 96 4 1 7 Blank test and inter laboratory comparison 97 4 2
6. Room temperature C Figure 2 1 Relationship between condensations sample temperature humidity and room temperature Curved lines show the border of condensation at each sample ambient air temperature i Manual for Air Concentration Monitoring 2 2 4 Height of sample inlet Air concentration monitoring to provide air pollution data to the general public in a timely manner and to support compliance with ambient air quality standards is generally carried out at the height of usual living and breathing of person The sampling height however is also decided in consideration with the regional representativeness the vertical profile of air pollutants the practical matters in the monitoring etc US Environmental Protection Agency USEPA prescribes the height of sampling inlet of automatic monitor for SO O3 NO and PM shall be in the range from 2 0 m to 15 m above ground U S Environmental Protection Agency 2013 EMEP recommends to monitor ambient ozone concentration at least at the height of 2 0 m above ground Norwegian Institute for Air Research 2001 On the other hands Japanese ambient air continuous surveillance manual Ministry of the Environment Japan 2010 regulates the height of sampling for SO NO and O is 1 5 m lt h lt 10 m above the ground and the height for PM 9 and PM25 is 3 m lt h lt 10 m above the ground because of preventing influence of the ground such as winding up the sand etc When th
7. 3 Filter The glass fiber filter with the surface treatment etc that processed into exclusive cartridge is used as a collection device 4 Notes for measurements 1 Sampling air system It follows the description in the section of the B ray absorption method automatic monitor Section 3 1 4 1 2 Exchange of filter The mass flow rate is always displayed in the TEOM method The filter should be exchanged before it becomes impossible to maintain the setting flow rate At the site which tends to be influenced by the automobile exhaust particles the frequency of the filter exchange should be increased because it quickly impossible to maintain the setting flow rate even if the total collection amount is small When the filter is exchanged the display of the frequency value should be carefully checked When the fluctuation is not stable after 10 minutes or more the attachment of the filter should be confirmed Aq Manual for Air Concentration Monitoring 3 Flow stabilizer In the filter oscillation method the sample air is introduced with the flow rate of 16 7 L min in order to prevent particles depositing on the surface of the sampling tube 1 5 3 0 L min of the total flow is separated by the isokinetic flow splitter tube and then led into the detector The mass flow controller is used for controlling the flow rate 4 Confirming actual flow The actual flow rate of the sample air is determined by the standard flow meter conn
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9. 2 Dunk cellulose filters into No 1 beaker and stir them with a glass stick 3 Pull up the filter from the No 1 beaker using plastic tweezers dunk it in the No 2 beaker for the rinse 4 Pull up the filter from the No 2 beaker using plastic tweezers dunk it in the No 3 beaker for the rinse 5 Pull up the filter from the No 3 beaker using plastic tweezers and put the filter between two sheets of large cellulose sheet e g ADVANTEC No 590 Toyo Roshi Kaisha Ltd to absorb extra water from the impregnated filter 6 Keep the impregnated filter into a clean plastic filter case and seal it in a polyethylene bag with marking H3PO4 7 Back to step 2 for next filter But maximum 20 filters could be prepared by one set of solution Filters especially impregnated one should be always sealed up to avoid the contamination by unexpected ambient pollutants before or after the sampling time Disposable gloves and tweezers should be used when handling the filters Cellulose filters should be cleaned if necessary before use Impregnation solutions should be used up on the same day of preparation After each cleaning and drying process 3 filters should be analyzed for major ions and blank values should be determined If the blank level is too high all filters from the impregnation batch should be thrown then a new batch should be made If the blank level is within usual one the storage bags should be marked and dated Impregnated filters shoul
10. Gas cylinders with standard gas must be handled with great care Never move or transport a gas cylinder with regulator installed or valve exposed Moreover regulator should be stored in sealed plastic bag for storage or during transportation in order to avoid contamination When a gas cylinder and or regulator is replaced or reused after exposure to air great care must be taken to avoid any back diffusion of air into the gas cylinder This is especially important for NO gas cylinder as back diffused O2 will oxidize NO to NO3 3 1 4 PMio and PM monitors 3 1 4 1 B ray absorption method 1 Principle The B ray absorption method is most popular for the particulate matter PM mass concentration monitoring recently An indicated value as a mass concentration is obtained from an increase of absorption amount of B ray due to the particles collected on a filter paper The B ray analyzer is an instrument based on the principle that the absorption rate of B ray irradiation by the particulate matter collected on the filter paper gives information about its quantity The relationship between the intensity of B ray transmitted and the dust quantity is expressed by the following equation 40 Manual for Air Concentration Monitoring I Ip exp um xm 3 12 I ray intensity transmitted through filter and particulate Io ray intensity transmitted only through filter um Mass absorption coefficient cm g xm Mass of particulate matt
11. In order to keep constant condition of the instruments the responsible person must 120 Manual for Air Concentration Monitoring prepare the check list and the results must be recorded in the daily check reporting form Because the instruments are different for station by station this record form should be prepared for each station as appropriate A recording chart of an automatic monitor should be described the check date and time the name of operator the contents of daily check missing data period etc because it would be important record when questions on the monitoring data are raised Moreover if abnormalities are found and the problem cannot be solved the operator must take the condition as much as possible so that proper repair can be conducted Table 5 1 The contents of maintenance Sections Objectives Frequency Contents 1 Confirming the operating To operate the of the instruments automatic monitors and 2 Replacement or addition of l samplers in a stable Once consumables Daily check 5 i ar condition week 3 Simple calibration and To retrieve data and check the results collect the samples 4 Cleaning and replacement the simple parts To keep an automatic 1 Test of flow tubes and a monitors in good manifold conditions Test of detection parts Periodical To prevent instrumental Once 3 Test of control and data check failure year transmission parts To check standard 4 Test of amplification and i
12. P NH G NH4 2S0 P 3 Artifacts of HCI I NaCl P HNO G HCI G NaNO P II 2NaCl P H2SO0 P 2HCIl G Na2SO P IHI NH CI P HCI G NH G P and G mean particle and gas respectively 86 Manual for Air Concentration Monitoring 4 1 3 Specifications of filters The filter material should not absorb SO and should have acceptable collection efficiency for submicron particles Cellulose filters are acceptable for this purpose but membrane filters e g Teflon are preferred 1 Filters for aerosol sampling Aerosols are collected at the first stage The first stage filter is mounted in front of the other filters collecting gases The material of the aerosol filter should not absorb acid and alkali gases and should have acceptable efficiency to collect sub micron particles For this purpose Teflon PTFE polytetrafluoro ethylene filters are preferred It was evaluated that the differences in the use of a quartz filter and a PTFE filter as the first F0 stage filter and the total material to be collected by the four stage filter pack method was almost the same irrespectively of the first stage filter used Aikawa et al 2010 2 Filters for nitric acid sampling The second stage filter is designated to collect nitric acid Nitric acid passes through the first stage and is caught on the second filter in principle In order to collect nitric acid separately from o
13. 6 Check whether precision check result exceeds 20 7 Record the result on a control chart Complete the precision check data sheet 7 6 1 4 Particulate matter The filter paper that has little air flow resistance and fully removes a particulate matter is put in the filter holder and then it is connected to the sampling inlet 24 hour sampling test is carried out by using this blank monitoring system The precision can be determined as the relative standard deviation of duplicated measurement results using this blank filter or standard filter For each PMjo automatic monitoring instrument the measurement of precision should be done at least 4 times a year As for a PMjo monitor the accuracy can be determined as relative error between monitoring value and setting value of flow rate or measuring results of the standard filter using automatic instrument or gravitational filter weight method The determination of accuracy should be done once for three months for one PM automatic monitoring instrument The accuracy test should be done before zero setting and any parameters of the instrument 7 6 1 5 Manual monitoring For manual monitoring method the precision test can be determined as relative standard deviation of duplicated measurement using blank filter or standard filter Blank filters are treated exactly like a sample even to the point of mounting them in the sampling device The only difference is that air is not drawn through them
14. CF NO7 N lon chromatography Section 4 NH4 N Spectrophotometry or Section 4 ion chromatography 4 2 4 Calculation of results The results from the chemical analyzes will be given in ug ml of the respective ions After subtraction of blank values the following equations are used for the subsequent calculation of the concentrations of HNO3 N SO S and NH N in air Norwegian Institute for Air Research 2001 HNO N ug m D1 D2 0 94 x 10 V 4 3 SOS g m D1 D2 0 96 x 10 V 4 4 NH3 N ug m D3x10 V 4 5 Where D1 D2 and D3 stand for the concentrations of the relevant components in the respective denuder extracts and V is the sample air volume in m The correction factors are based on theoretically calculated absorption efficiencies and it is assumed that interfering particles and other substances e g PAN are collected with the same efficiencies in D1 and D2 102 Manual for Air Concentration Monitoring Correspondingly NO3 N particles F1 F2 2 5xD2 x10 V 4 6 NH 4 N particles F1 F3 x10 V 4 7 SO S particles F1 2 5xD2 x10 V 4 8 Note that if the absorption capacity of denuder D3 for ammonia is exceeded F3 will retain gaseous ammonia which has passed through the denuder system Therefore if this amount of ammonium N collected on F1 and F3 is significantly larger than the equivalent amount needed to balance the nitrate and sulfate on F1 and F2 the calculated
15. Frequency after the increase in mass Hz Dynamic check The dynamic check of the automatic monitor using the ambient air is performed by the comparison with the standard filter method The remaining sample passed through the isokinetic distributor equipped in the automatic monitor is collected by the filter The filter is treated according to the standard method in which the filter is weighed by using the precision balance under the prescribed conditions of temperature and relative humidity The differences 56 Manual for Air Concentration Monitoring between the automatic and standard method is required within 10 ug m or 10 3 Dynamic calibration It applies to the B ray absorption method automatic measurement monitor 3 2 DOAS measurement 3 2 1 Principle of DOAS 1 Introduction The DOAS technique allows the determination of different trace gas concentrations at the same time without disturbing the chemical behaviors of the substances to be investigated Platt 1994 With the DOAS technique the absorption of light which is unique for different trace gases is measured Atoms and molecules absorb specific wavelengths of light the wavelength determined what electronic transitions are induced In addition molecules are excited to higher rotational and vibrational levels As they differ in their moments of inertia and their strength of bonding they show different rotational and vibrational levels That is the reason that the ab
16. Manual PM 1 ug m 1 hour Auto Particulate matter 1 week components Cone 7 3 Monitoring site Site audit 7 3 1 Site selection Selection of sampling sites is a critical factor in the monitoring and the siting criteria are described in the Guidelines for Acid Deposition Monitoring in East Asia EANET 137 Manual for Air Concentration Monitoring 2000 and the relevant technical manuals The same sites used for wet deposition monitoring are recommended for air concentration monitoring When air concentration monitoring is difficult at a wet deposition monitoring site a new sampling site should be selected by sufficient consideration for uniformity of ground surface in addition to the criteria for wet deposition monitoring EANET 2010 As described in Section 2 2 4 intake points of automatic instruments should be the height of sampling for SO2 NO NO and O is 1 5 m lt h lt 10 m above the ground and the height for PMi9 and PM25 is 3 m lt h lt 10m above the ground It should also be noted that the environmental conditions such as temperature and humidity in which instruments are located should be carefully assessed Air conditioning should be provided in the station where automatic instruments are located However if the temperature in the station is significantly lower than outside temperature it will lead to condensation of water in sample inlet lines and measurement errors Such measurement errors may happe
17. Moreover the acidic circumstance tends to proceed the degradation of the equipment When the diffusion tube is exchanged the monitored values after the last maintenance should be verified and judged their adoption If those values are adopted as the reference value or accepted after the correction by using any correction equation it is always necessary to put the note which explains the reliability of those values Sj Manual for Air Concentration Monitoring Sampling inlet PM particle size classifier Exhaust of the air for dehumidification Fag TEN Pump Pump controller a TEN Humidity sensor signal Osmosis film Solid line Flow of sample air Detector Dashed line The flow of the air for dehumidification controller Exhaust Figure 3 21 Dehumidifier system by the diffusion tube method 3 Dilution method This is the method to reduce the relative humidity by inflow of the particle free pure dry air into the sampling tube The model adopted this system presently has been operated in the two steps dilution procedure This system has the structure in which a part of sample air passed through the PM collection filter is dehumidified to produce pure dry air After that the air is mixed with the sample air and introduced to the detector Accordingly the air volume of filter passage is increased by the mixed pure dry air As the results it is necessary to pay attention that the PM and or the
18. and it is replaced if necessary 80 Manual for Air Concentration Monitoring iii It should be checked that the signal increases after sunrise and becomes zero after sunset iv It should be also confirmed that the instantaneous and integrated values are less than 1 4 kW m and 5 0 MJ m respectively 2 Periodical check i It should be checked whether there are any abnormalities on the glass dome ii Substantial change in color and detachment of pigment on the acceptance surface is checked iii Disconnection and loose connection in the output connector is checked iv Confirm the external outputs such as indicated values record values and telemeter outputs when the pseudo voltage equivalent to 5 0 MJ m2 is applied 3 3 6 Rain gauge Precipitation is defined as the quantity of rainwater which has reached on the ground surface or the monitoring surface during a certain time and it is expressed as the depth of rain water The precipitation is represented as a unit of mm and to be recorded up to 0 1 digits However when the minimum measurement unit of a rain gauge is 0 5 mm the amount less than 0 5 mm is round off to be 0 0 mm and the amount over 0 5 mm and below 1 0 mm is round off to be 0 5 mm 1 Principle of measurement Rainwater is introduced from a funnel through a filtering equipment and into the one side of the reversing measure Fig 3 32 When the one side is filled with rainwater the gravity center
19. o 4 P T absorption cross section of absorber i c J 58 Manual for Air Concentration Monitoring concentration of absorber i L total light path length Some characteristics of the contributing processes are of special significance for the analysis of atmospheric absorption spectra The scattering coefficients eg and em depend mainly on two factors the location along the light path and the wavelength Of crucial importance is the fact that both coefficients depend on the wavelength in a monotonous manner the Mie scattering coefficient em which describes the scattering on particles larger than the wavelength shows a dependence on 4 The scattering on particles or molecules smaller than the actual wavelength is described by the Rayleigh coefficient er and depends on 4 3 Basic principle As every molecule is characterized by the composition and arrangement of the elements it consists of its electronic and ro vibronic states also generate a characteristic absorption cross section The cross sections of all absorbers o therefore form a basis in the mathematical sense from which each absorption spectrum can be composed as a unique linear combination So the concentrations of all compounds that absorb in the observed wavelength range can be measured simultaneously But the basic Lambert Beer Law cannot be applied to trace gas concentration measurements in the atmosphere It is impossible to quantify all extinction
20. samples for most of the measured species are similar between weekly annular denuder systems and composited filter packs Sickle et al 1999 Sampling artifacts due to the volatility of ammonium nitrate and possibly due to interaction with other atmospheric constituents make separation of these gases and particles by a simple aerosol filter unreliable This can be achieved using denuders where one takes advantage of the different diffusion velocities of gas and aerosol particles in a sampling device which is simply a tube coated on the inside by an absorbing reagent usually sodium chloride or sodium carbonate The same sampling principle may also be used for sampling of ammonia using citric oxalic or phosphoric acid as the absorbent Particulate organic acid is also important and thus could be considered for monitoring in future Because the diffusion speed of ammonia in air is about twice that of nitric acid a shorter diffusion tube will achieve gt 95 absorption efficiency If the flow is laminar minimal deposition of particles occur and if the tube has proper dimensions in relation to the flow rate and the diffusion speed of gaseous nitric acid in air nitric acid is efficiently deposited to the walls of the tube Since the denuders give a possibility to determine the individual concentrations of HNO g and NOs particle and NH g and NH particle it is a recommended method to use in the EMEP network Norwegian Institute for Ai
21. type anemometer 3 Manual for Air Concentration Monitoring B Wind velocity The power generation type outputs the voltage inducing by AC generator attached to the axis of a propeller which is proportional to wind velocity and rotates The pulse type is outputting the calculation results of pulse counts proportional to wind velocity during rotation of the propeller by a wind The rotary light encoder type 5 bits or 8 bits and the magnetic system are used for the wind direction and the pulse type a magnetic pulse a lightwave pulse is used for the wind velocity 2 Ultrasonic type The ultrasonic type measures the speed of the sound which spreads in the air changing with wind velocity and temperature The wind direction and the wind velocity are outputted by the vector composition of each propagation time of the X axis horizontal and the Y axis vertical direction measuring the speed of the ultrasonic wave of the high frequency which is not felt for human and spreads in the air Generally the speed of the sound wave signal which mutually transmitted between the two points on the horizontal surface in the air is determined by the wind velocity component of the direction of the two points and by the speed of sound in the still air For example of an typical ultrasonic type wind direction anemometer the sum and difference of the time when the 100 kHz ultrasonic wave is mutually transmitted between the transducers which are located a
22. 38 Manual for Air Concentration Monitoring country e g once per year The Network Center NC may provide the transfer standard by the request of the country which does not have the primary standard Air Inlet Particle Filter Only for UV Ambient ozone Analyzer UV Detector Signal Processing Electronics C UV Source Lamp Flow Meter Figure 3 16 UV photometric ozone measurement system Norwegian Institute for Air Research 2001 3 Calibration method with a secondary standard and a transfer standard It is desired that the primary monitor calibrates every monitor located in monitoring stations But when the primary monitor cannot be used easily the secondary standard and a transfer standard can be prepared A secondary standard shall be calibrated against the primary monitor at least once per year and its accuracy shall be maintained within 2 ppb at level of 200 ppb between successive primary calibrations And a transfer standard shall be calibrated against the secondary standard every six month and its accuracy shall be maintained within 2ppb at level of 200 ppb between successive secondary calibrations The recommended portable transfer standard calibration method is a secondary standard with its own zero air and ozone supply The other acceptable transfer standard calibration methods are the gas phase titration of excess nitric oxide by ozone or vice versa For details see the relevant referenc
23. 83 Platt U Perner D Patz H W 1979 Simultaneous Measurement of Atmospheric CH20 O and NO by Differential Optical Absorption Journal of Geophysical Research 84 6329 6335 Stutz J Platt U 1997 Improving long path differential optical absorption spectroscopy with a quartz fiber mode mixer Applied Optics 36 1105 1115 Stutz J Kim E S Bruno P Perrino C Febo A 2000 UV visible absorption cross sections of nitrous acid Journal of Geophysical Research 105 D11 14585 14592 U S Environmental Protection Agency 2013 Transfer Standards for Calibration of Air Monitoring Analyzers for Ozone 67p U S Environmental Protection Agency 1997 Revised Requirements for Designation of Reference and Equivalent Methods for PM2s and Ambient Air Quality Surveillance for Particulate Matter Final Rule 40 CFR part 58 Federal Register 62 138 38830 38854 U S Environmental Protection Agency 2014 Electric Code of Federal Regulation Title 40 Protection of Environment Part 53 Ambient Air Monitoring Reference and Equipment Methods Subpart D Procedures for Testing Performance Characteristics of Methods for PM jo 2014 1 23 Access Vandaele A C Simon P C Guilmot J M Carleer M Colin R 1994 SO absorption cross section measurement in the UV using a Fourier transform spectrometer Journal of Geophysical Research 99 D12 25599 25605 Voigt S Orphal J Bogumil K and Burrows J P 2001 The
24. Passive samplers are being used for a variety of applications and for a variety of species The specific information for the measurement of ambient SO2 NO2 NH3 and O concentrations is described as follows 1 SO2 The measurement of SO using passive samplers utilizes a NaOH impregnated cellulose filter On the filter sulfite is oxidized to sulfate during sampling and the sulfate amount is analyzed using ion chromatography IC The cellulose filters also were found to have a sulfate blank that could not be completely reduced It was discovered that the use of a very fine stainless steel net in parallel with the impregnated cellulose filters eliminated this extra peak Thus a steel net placed in the outer cap is 105 Manual for Air Concentration Monitoring recommended both to insure molecular diffusion and to reduce chemical interferences The short samplers have a measurement range of from 0 05 to 40 ppb for a sampling time of 2 months or 0 1 to 80 ppb for monthly sampling 2 NO The most commonly used sorbent for NO sampling is triethanolamine but stability problems have been encountered with its use The arsenite and ethylene glycol has been reported to perform the best and is the one recommended for use WMO GAW 1997 It also has the added benefit of being insensitive to light and thus the impregnated filters can be stored for several months before as well as after sampling On the filters NOz is converted to nitrit
25. Technical Manual for Wet Deposition Monitoring in East Asia 2010 EANET 2010 If the detection would be still difficult in spite of increasing the air flow rate the solvent volume might be set less than 20 ml but to be enough for analyzing 4 1 6 Determinations of concentrations and data reporting The concentrations of gas and aerosol components in the air are basically determined as follows Cair X net Csoi X Vso Vair 4 1 Cair concentration in the air nmol m net Csa net concentration in the solution mg l Vgo1 volume of the solution ml Vair volume of the sampled air corrected at 20 C 1 atm m M molecular weight a 10 M The net Cso should be calculated by the equation 4 2 net Csol Cso Sample 7 Cso Blank 4 2 Col Sample Concentration in the solution from the sample filter Col Blank Median concentration in the solutions from the blank filter Regarding the determinations of concentrations the equations are summarized in Table 4 3 Table 4 3 Equations for determinations of concentrations Species M Equation SO 96 06 NO 62 01 cr 35 45 Nat 22 99 z 39 10 Cair amp x net Cgo1 Fo X Vso Vair NH 18 04 Ca 40 08 Mg 24 31 SO 96 06 S047 Cair a x net Cso r net Csot F2 x Vsot V Air HNO 62 01 NO3 Cair amp X net Cso F1 X Vsol V air HCl 35 45 CI Cair amp X net Cso F1 net Cso F2 X Vso Vair
26. The dirt on the inner surface of the sampling tube by adhering of particles will cause the reduction of measurement accuracy because the adsorption or decomposition of the species to be measured will occur on the inner surface For this reason the sampling tube should be washed or replaced periodically Although the frequency depends on the condition of the sampling tube it is required to carry out the wash or replacement once or more per year at least Also the inner surface of the manifold shall be washed cleaning once a year or more 2 2 6 Note on monitor installation It is desired to have the following condition as for the location of the monitor i Vibration Since a monitor has a vibratory source such as a suction pump the vibration will be transmitted to the other monitors especially on a wooden floor it is expected to take measures for the floor vibration if possible ii Corrosive gases and particulates _16 Manual for Air Concentration Monitoring Corrosive gas and particulates may cause the loose connection of the electric part of the instruments For this reason it is necessary to prevent invasion of these substances into the station and to avoid use and preservation of the reagents which generate the corrosive gas in the station iii Low humidity and comparable temperature at the calibration High humidity in the station causes loose connection such like the item ii The temperature in the station should be compa
27. a manual zero span check immediately before the precision check 7 Enter the NO2 Act and adjusted NO response Adj NO2 of analyzer into the precision check data sheet for NO and then calculate the percentage difference Check whether the difference exceeds 20 8 Check the analyzer and calibrator is in normal operating condition 9 Complete the precision check and converter efficiency data sheets 10 Record the result on the precision check control chart Automatic method 11 When the precision check is done by using automatic method the steps 1 to 4 will be performed automatically Then it will attain the difference of NO2 and complete other related procedures until the step 10 7 6 1 3 O3 precision check A precision check should be performed at least bi weekly The result of 90 10 ppb level in a dynamic calibration can be used as a precision check result Automatic method 1 Normally the precision check is being done automatically once every two weeks 144 2 3 Manual for Air Concentration Monitoring Therefore staff should check the calibration summary and complete the precision check data sheet and record the percentage difference Check whether precision check result exceeds 20 Record the result on the precision check control chart Manual Method on site Precision check by Model 146 calibrator 1 2 3 4 5 6 Disconnect the sample line of the ozone analyzer from the mani
28. at the lowest determination limit In order to define these parameters a standard solution should be prepared at concentration levels near the lower determination limit Analyze the above standard solution repeating for five times to determine the standard deviation s d over the five runs The not detected and lowest determination limit are defined as three and ten times of the standard deviation respectively as shown below Not detected 3 s d 7 2 Lowest determination limit 10 s d 7 3 The numerical figures for these measures may differ considerably depending upon experimental conditions including the types of instruments the instrumental history and operator experience For this reason the standard deviation should be determined whenever the analytical conditions are changed 7 5 Data management There are various data check procedures Typical data check procedures include 139 Manual for Air Concentration Monitoring routine data check confirmation of measured data and data screening When the sensitivity of instruments is not stable or when data significantly differ from the range of other measured data reliability is considered to be low and the data may need to be treated as abnormal 7 5 1 Routine data check Routine data check is the most fundamental process to identify abnormal data by comparing the transmitted on line data with the pre determined standard values when the data tables are pr
29. be properly reported in the record sheet and the report should be submitted to the Network Center NC through the National Center upon request The example of field record sheet is shown in the Fig 5 3 5 5 Maintenance record According to the recent development of monitoring instruments most of instruments can be used for more than 5 years It is important to take records of the status of monitoring instrument when one try to analyze long term trends of air concentrations The necessary items of the maintenance record are shown below e Name of station e Name and type of instruments e Regular inspection of instruments Date Contents Results e Calibration records Date Species Method Range Spen and Zero factor e Instrumental failure and repairs Date Contents Results 5 6 Safety management It is important to consider safety management regarding high pressure gas cylinders disposal of chemicals and parts of monitoring instruments 5 6 1 Management of high pressure gas cylinders The gas cylinder should be fixed by chains and the storage room should have good 123 Manual for Air Concentration Monitoring ial Fow Rat Final Flow Rate Pf mmHg Field Operator Laboratory Staff Checked by Figure 5 3 Example of field record sheet Environmental Resources Management 2007 ventilation condition The gas cylinder has to be connected to valve and the pressure should meet the requirement of instrumen
30. buildings and historical monuments Monitoring data at these sites may also be useful for the assessment of air pollution and its trends in urban areas 2 2 Site facilities and Instrumentation Electricity Housing Air conditioning Inlet Data communication monitor arrangement etc 2 2 1 Design of monitoring station The design of a monitoring station depends on the type of housing such as using a part of an existing building or construction of single house In addition the station is expected to be designed considering with the harmonization to the surrounding scenery Manual for Air Concentration Monitoring A PM mass concentration monitor should be installed outside of the station fundamentally due to the difficulty and the disadvantage to make a hole which penetrates the station roof for a passage of a sampling tube 1 Case of using a part of an existing building When a part of an existing building is used as the station it is necessary to ensure an area isolated with a partition and to display all equipment in the area The sampling inlet should be placed at the position minimizing the contamination from the building and minimizing the distance from the inlet to the automatic monitor 2 Case of construction of single house 1 Fixed type 2 2 2 2 Generally there are some possible structures of a fixed station made of wooden prefab concrete block etc with some advantages and disadvantages A
31. but also check external outputs such as indicated values and telemeter outputs when the pseudo pulse is applied Funnel Wire net Filtering equipment Fall measure Drainage pipe Bearing Legs Figure 3 32 Example for fall measure type rain gauge References Acid Deposition Monitoring Network in East Asia 2010 Technical Manual for Wet Deposition Monitoring in East Asia 2010 Network Center of EANET 11 1p Gomer T Brauers T Heintz F Stutz J and Platt U 1996 MFC User Manual ver 1 98 Technical Report Institut fur Umweltphysik Universitat Heidelberg Hermans C Vandaele A C Carleer M Fally S Colin R Jenouvrier A Coquart B and Merienne M F 1999 Absorption cross sections of atmospheric constituents NO2 O2 and H2O Environmental Science and Pollution Research 6 151 158 82 Manual for Air Concentration Monitoring Meller R Moortgat G K 2000 Temperature dependence of the absorption cross sections of formaldehyde between 223 and 323 K in the wavelength Journal of Geophysical Research 105 D6 7089 7101 Ministry of the Environment Japan 2010 Ambient air continuous surveillance manual 6 Edition p 107 in Japanese Norwegian Institute for Air Research 2001 EMEP Manual for Sampling and Chemical Analysis 301p Platt U 1994 Differential optical absorption spectroscopy DOAS Chemical Analysis Series John Wiley amp Sons Inc 127 27
32. circumference environment growth of trees new building etc is required 3 3 2 Wind direction anemometer A wind is denoted by vector quantity of wind direction and wind velocity Because the wind direction and wind velocity in the environment are changed continuously the hourly value is usually obtained by the average value for the last 10 minutes on the hour Wind direction shows where the wind blows from and it is shown by the clockwise rotation angle which makes 16 directions The north direction denotes 0 degrees Wind velocity is the distance which the air moves in unit time It is measured in m s unit and to be recorded up to 0 1 digits Although there are many kinds of the meteorological instruments for monitoring wind direction and wind velocity the windmill type wind direction anemometer and the ultrasonic type wind direction anemometer are generally used for air pollution continuous monitoring measurement Propeller Tail Maanetic dispatch vehicle 1 Principle of measurement 1 Windmill type A Wind direction A tail rotates following a _ wind direction Arithmetic process ing of the signal from transmitters including a synchronization a potentiometer or a rotary light Encoder encoder type directly linked with a the axis of the tail is carried out eee and the wind direction is outputted in the range from 0 to 540 degree covering the direction NESWNES Figure 3 31 Example for Windmill Fig 3 31
33. cm Therefore spectra with these extreme SO absorption values were omitted in the O3 IM SM yf 20 d 17 Apr 18 Apr 19 Apr 20 Apr O mixing ratio ppb 23 Apr 24 Apr 25 Apr 26 Apr 27 Apr Date local Figure 3 30 Average O mixing ratio along the measurement light path for the two time periods in which the night time measurements took place April 17 20 2007 and April 23 27 2007 69 Manual for Air Concentration Monitoring Fig 3 30 shows the average O mixing ratio along the light path for the time periods in which the night time measurements took place April 17 20 2007 and April 23 27 2007 The ambient O mixing ratios varied between 20 and 40 ppb with the higher values typically occurring during daylight hours 3 2 4 Evaluation procedure The evaluation is usually performed with the software MFC Gomer et al 1996 which uses the spectra simulation and analysis model Briefly the fitting algorithm processed as follows i Correction of offset and dark current in the lamp reference spectrum ii High pass filtering application of the logarithm and smoothing of the lamp spectrum iii Linear fit of the diode structure reference spectrum and a polynomial of 5th order to the lamp spectrum Extraction of the residual structure of this fit for use as a lamp reference iv Correction of offset and stray light by offset corrected atmospheric stray light spectrum in the atmospheric absor
34. coating procedure a source of clean dry air is needed Compressed air must be filtered and may have to be scrubbed Passing the air through 2 tubes filled with cotton or filter paper impregnated with respectively sodium carbonate and citric acid will be safeguards against contamination It is also possible to use clean and dry nitrogen from a gas cylinder 100 Manual for Air Concentration Monitoring Put on a screw thread cap on one end of the denuder add 2 3 ml of the coating solution and rotate the denuder so that all internal surfaces are wetted Pour off excess liquid take off the screw cap and put on another cap with connection to the dry air source Pass dry air through the denuder for approximately 10 minutes and then connected with the other end to repeat drying Observe the evaporation of the liquid film in the denuder and continue for a few seconds more to make sure that the evaporation is complete Close the denuder with screw caps 2 Sampling At least 3 of the denuders should be set aside for the determination of blank values for each batch of denuders which is being prepared in this way Sodium chloride is used as an internal coating for the absorption of nitric acid in D1 This absorbent may partly absorb SO gt and will not absorb nitrous acid or PAN One set of denuders and one filter pack should be reserved for use as field blanks at once for 2 or 3 measurements These are to be sent to the field sampling
35. corrosion etc 2 Operation of instruments 3 Cleaning of sampling parts 1 4 Sampling methods 1 Sampler an monitors including documentation of check and maintenance 2 Sampling intervals 2 Sample transportation and storage for manual monitoring 2 1 Transportation of samples 2 2 Sample storage 1 On site storage 2 Laboratory storage 3 Chemical analysis 3 1 Appointment of analysis staff and their supervisors for each item 3 2 Training plan 3 3 Pure water 1 Daily maintenance 115 3 4 3 5 3 6 Manual for Air Concentration Monitoring 2 Documentation of maintenance Measurement by automatic instruments 1 Measuring conditions of instruments 2 Calibration 3 Performance tests sensitivity stability interference and its removal documentation of repair 4 Calculation of lowest detection limits and lowest determination limits 5 Documentation of maintenance Operating procedures for measurements 1 Preparation of calibration curves 2 Measurement analysis of samples 3 Repeated measurements analyzes 4 Check of sensitivity fluctuations Treatment of measurement results 1 Calculation of concentrations 2 Measurement of sensitivity fluctuations 3 Repeat measurements analyzes 4 Calculation of ion balances 5 Comparison of measured and calculated electric conductivity if applicable 4 Quality assurance and quality control 4 1 4 2 4 3 Evaluation of manual sampling 1 Compar
36. differential absorption cross section of ozone An integral part of the spectra evaluation is represented by the trace gas references fitted to the measured spectra As already discussed above these references are generated by convolution with the instrument function from high resolution cross section spectra Table 3 1 presents the literature cross sections that were used for the trace gas concentration retrieval The spectral resolution both for the literature cross sections and the convolution algorithm is of crucial importance for the quality of the reference spectra the highest resolution of the literature spectra and of the wavelength grid used for the convolution guarantee that under sampling effects are effectively suspended and that the Lambert Beer Law is also valid for the lower resolutions For the convolution all reference spectra were interpolated to a wavelength grid of 0 001 nm and subsequently processed using the normalized instrument function The instrument function was derived by normalizing the area below a measured spectrum of the mercury emission line at 366 33 nm This line is well isolated from other lines and therefore ideally suited for the determination of the instrument function Table 3 1 Specifications and references for the trace gas absorption cross sections Species Source Rel error Resolution NO FTIR 3 5 0 5 1 cm O3 FTIR 3 7 5 cm O4 FTIR n a lcm FTIR Fourier transform spectrometer G
37. excess should be added to the NH N concentration determined from D3 4 3 Passive sampler Passive samplers provide a simple and cost effective way of monitoring specific species at urban regional and global scales and offer broad capacity building opportunities While the appropriateness of the use of passive samplers has been questioned in the past due to concerns related to reliability and accuracy current developments and studies indicate that passive samplers are now a viable option for many species and many applications Ohizumi et al 2013 Passive samplers offer a wide variety of advantages for use in the field There is no need for calibration gases and electricity and thus they are easy to be fixed in the field The passive samplers are simply fixed inside a shelter to avoid splashing from precipitation and strong wind which is attached to a pole at typically 1 meter height They are small inexpensive and provide time integrated samples One of the benefits is that artifact caused by evaporation of particles can be avoided The time resolution of passive sampler is relatively low so the passive sampler can mainly monitor the weekly average concentrations They can be used to check spatial variability in pollution fields and the representativeness of locations of advanced sampling stations used to measure background concentrations at places where other measurements are difficult and can be used also in urban environment by changi
38. flash trigger and the sampling of signal The voltage is further amplified and level shifted based on the setting of zero and span pots The conditioned signal is then sent to a digital display and a recorder amplifier The recording amplifier converts the conditioned signal to 0 1 V DC analogue output for recording purpose The output from the photodetector is compared to the reference signal and the difference is used to control the lamp voltage Any fluctuation in the UV lamp output is therefore compensated The temperature effects in the electrical and optical component are eliminated by a temperature control circuitry which maintains the reaction chamber at a stable temperature of about 40 C The lamp power supply provides a pulsating voltage of 800 1200 V for the generation of pulsating ultraviolet light The high voltage supply generates a stable DC voltage of around 700 to 2000 V for the PMT operation 3 1 1 2 SO multi point calibration procedures Dynamic calibration by dilution 1 2 3 4 5 6 7 8 9 Manual for Air Concentration Monitoring Record the analyzer site and transfer standard parameters on the calibration data sheet Check and record the ID number and calibration expiry date of the gas cylinder Carry out a visual check of the analyzer prior to calibration Ensure that the mass flow controllers of the dynamic calibrator e g TECO 146 Thermo Fisher Scientific Inc have b
39. in each National Center and technical training for leading to technicians in national or local governments in East Asian countries as follows Training by the Network Center Based on the results of the First Meeting of the Interim Scientific Advisory Group held in October 1998 The Interim NC had carried out the Ist EANET Training Workshop for senior officials responsible for implementation of the monitoring activities in each National Center to disseminate the details of the QA QC programs and the data reporting procedures and formats etc Currently the NC provides the EANET individual training course inviting beginner operators in participating countries every years The JICA Trainig Course on Monitoring and Control Technologies of Acid Deposition has been carried out annually which includes subjects on air concentration monitoring The NC should continue the training on air concentration and dry deposition monitoring for experts in the participating countries Training by the National Center in each participating country The National Center in each participating country should prepare a national training program and implement as appropriate training on methodologies of air concentration monitoring The National Center should also provide guidance for the preparation of SOPs to national organizations that carry out air concentration monitoring 152 Manual for Air Concentration Monitoring References Acid Deposition Monit
40. into test tubes 12 20 ml by using clean tweezers and plastic glove Pour 10 ml deionized water into test tubes for SO and O analysis If using the IC for NO2 and NOx analysis pour 10 ml deionized water into test tubes If using the spectrophotometer for NOz and NOx analysis pour 8 ml deionized water into test tubes Stop up the test tubes with cap and then store them in refrigerator until chemical analysis Clean of sampler 108 Manual for Air Concentration Monitoring Store passive sampler into a wire netting bag Soak wire netting bag into an ultrasonic bath for 10 minutes Rinse the wire netting bag with deionized water and then dry it in laboratory avoiding ambient air contamination 4 3 4 Procedures of the chemical analysis Plastic glove test tube or plastic tube water bath sample vial and micro pipetter should be prepared for pretreatment of samples Chemical analysis can be done using IC or spectrophotometer Before analysis sample temperature should be returned to room temperature when samples are stored in refrigerator The number of ion standard levels should be more than 5 In the same way as filter pack ion chromatography IC is recommended for analysis of chemical components The analytical method should follow the procedures described by Technical Manual for Wet Deposition Monitoring in East Asia 2010 EANET 2010 The following describes the types of standards and some special apparatus and analytica
41. monitoring methods of NO are recommended to install especially in remote sites Photothermal Laser Deflection PLD is an analytical technique to measure in real time the mass concentration of particles and gaseous pollutants PLD uses a pump laser to locally heat the particle or gaseous species thus changing the refractive index of the surrounding gas to form a thermal lens A probe laser beam travelling through the thermal lens is temporarily deflected and the amount of deflection is proportional to the species mass concentration Cavity Ring Down Spectroscopy CRDS contains diode lasers to detect volatile organic compounds VOCs NO2 various radicals and atmospheric aerosol particles The typical detection limit of CRDS for VOCs and NO are in the parts per billion ppb to parts per trillion ppt range Kebabian et al 2008 Laser Induced fluorescence LIF equipment for selective NO measurement consists of a tunable broad band optical parametric oscillator laser pumped by the third harmonic of a Nd YAG laser is used as a fluorescence excitation source The difference signal between peak and bottom wavelength is used to determine the NO concentration The sensitivity of NO2 LIF is 30 pptv in 10 second integration time Second among the current monitoring methods only filter pack monitoring is feasible for monitoring of aerosol composition Because there are usually diurnal variations of dry deposition velocity hourly measurement of ai
42. moves to the opposite side and the measure is flipped at the precipitation of 0 5 mm The signal is counted at every flipping event and one pulse is transmitted to the connected electric circuit 2 Installation criteria It is necessary to choose the place where an air current becomes horizontal as much as possible and it should be kept away from a sloping ground a high ground a depressed ground a mountain ridge an outer wall of a rooftop in which a wind blows up Furthermore it is ideal to kept away from buildings and trees at the distance of 4 times or more of those height If it is impossible it selects from the place where there is no obstacles at an angle of elevation at more than 30 degrees Moreover the rain gauge should be placed horizontally and be avoided from the rebound of rain from the ground zgj Manual for Air Concentration Monitoring Because the rain gauge is used for wet deposition monitoring in some stations the place should be satisfied with the criteria of Technical Manual for Wet Deposition Monitoring in East Asia 2010 EANET 2010 3 Maintenance protocol 1 Daily check Remove garbage such as leaves and insects on the filtering equipment other inner parts and a water exhaust pipe and clean the inner surface of the reversing measure 2 Periodic check and maintenance Electronic parts such as a reed switch and connector are cleaned It is carried out not only cleaning of a reed switch and a connector
43. network QA QC programs and will provide appropriate guidance and advice to the participating countries based on this QA QC program The NC should prepare reports on the QA QC activities implemented by the participating countries and the QA QC levels with other relevant networks The NC should provide technical support as appropriate to each National Center in order to attain such objectives as follows l31 Manual for Air Concentration Monitoring 1 Preparation and implementation of the QA QC programs Appointment of the network QA QC manager Development of data quality objectives DQOs Provision of information for preparing SOPs Implementation of inter laboratory comparison survey e Assurance that adequate reference materials are used Exchange of information with and technical support for National Centers e Comparative analysis of sampling and analysis methods in the participating countries and development of technical documents 2 Preparation of the data report and the report on QA QC implementation 3 Development and implementation of training programs for participating countries 4 Comparative analysis of QA QC activities with other networks such as EMEP and WMO 7 8 Training programs It is necessary to improve knowledge and expertise related to air concentration monitoring Therefore the NC and the others should undertake training for personnel responsible for the implementation of the monitoring activities
44. of a monitor with possibility to break out and repair such as routine and periodic checks and maintenance and overhauls ii Troubleshooting the methods to deal with the anomalous behaviors and investigate their causes after breaking out and repairing such as emergency check An automatic monitor has the possibility of failures for example initial failure random failures during operating the monitors and wear out failures because of consuming their parts and themselves although a monitor is assured its fundamental 118 Manual for Air Concentration Monitoring specifications by qualification tests before installation It is important to plan the maintenance schedule of a monitor from the time when it is installing because the failure rate can be decreased by accurate maintenance Fig 5 1 shows an overview of the change of failure rate with operating time Infant Mortality Constant Failure Wear Out Period Period Failure Period Decreasing by Decreasing by faculty tests preventive maintenance Failure Rate Constant Random Failure Time Figure 5 1 Changes of failure rate with operating time Ministry of the Environment Japan 2010 This figure shows the relationship between the operating time of instruments and the failure rates and it is called The Bathtub Curve because its shape is like bathtub The failure rates of most instruments show the The Bathtub Curve The curve is classified into three
45. prefabricated structure is cost effective and also excellent in terms of ease of installation and removal On the other hand a concrete block structure is superior in durability fire protection and room management aspects Recently some prefab and lightweight aggregate panel structures which have high fire protection function comparable with the concrete block structure have developed However the station requires sufficient durability which can support the heavy automatic monitors with the weight of 100 kg or more Container type Ordinarily the container type station is made by aluminum or iron and the available space is less than that of the fixed type This type has some problems of fire prevention but it is easy to install it in the park etc where construction of the fixed building is restricted Moreover it is not difficult to move it when a problem on the representativeness of monitored values will be found However the container should be fixed firmly with a concrete foundation by using a anchor bolt in order to prevent damages such as inclination by earthquake typhoon etc It is also desirable to cover the outside of the container with the thermal insulation to enhance the air conditioning effect Facilities Station is required to have the facilities as the following 1 Electric facilities Manual for Air Concentration Monitoring 1 Electric capacity The electric facility is indispensable to operate the equipment T
46. problem 98 Manual for Air Concentration Monitoring The coated denuders are then followed by a three filter pack system The first filter is a PTFE membrane filter with high collection efficiency for submicron particles followed by a filter impregnated with potassium hydroxide for collection of nitric acid which may be evaporated from the particle filter and a filter impregnated with oxalic acid for the collection of ammonia which may also be evaporated Nitrous acid HNOz is also absorbed in the alkaline denuder but will normally not cause a significant interference as it is usually detected as nitrite in the sample extracts Glycerol prevents oxidation of nitrite to nitrate by ozone Nitrogen dioxide and PAN is partially absorbed as nitrite this interference in the eventual determination of nitrous acid may be corrected by the distribution of nitrite between the first and the second denuder 2 Timer and valve contr Z Manifold eT gt gt h Solenoid valve To pump and gas meter 3 stage i filter holder T 7 Jak 7 D m F omy a a IMi ma mu m a i mi 60 Watt painted light bulb D N
47. processes from an absorption spectrum measured on a light path in the real atmosphere even if all instrument specific spectral structures were known Additionally the knowledge of the trace gas concentrations gained from the characteristic absorption structures would still leave the problem of the quantification of extinction by scattering processes To overcome the problem that atmospheric scattering by molecules and particles and broadband absorption can hardly be quantified the DOAS technique divides the absorption cross section of trace gasses in two parts O A O poaa A E A 3 16 where o which is often referred to as the differential absorption cross section describes only the characteristic narrow band absorption structures of the different trace gasses The broad band structures caused by scattering and broad band absorption are characterized by o broad This is the key principle of DOAS see Fig 3 25 as it allows to split the exponent of the Lambert Beer Law in two parts the first varying only slowly with the wavelength and containing scattering processes and broad band absorption The second part characterizes the variations in transmitted intensity featuring a strong dependency on the wavelength due to narrow band trace gas absorption 59 Manual for Air Concentration Monitoring intensity cross section cm wavelength nm Figure 3 25 Principle of DOAS The absorption is broken down into two con
48. same order For equal light intensities of the different received light paths this additional stray light is in the order of 1 The convolution process and differences in the wavelength pixel mapping can cause errors up to 1 3 Errors made by the determination of the length of the absorption light path With the typical applied laser range finders this error is in the order of 0 1 Errors by the conversion of the concentration to mixing rations due to errors in the pressure and temperature If the simultaneous measured pressure and temperature are used for typical accuracies their influence is less than 1 2 Photon Noise op The photon noise p is in principle the theoretically achievable accuracy for measurements of electromagnetic radiation The detected photons ie the photoelectrons are Poisson distributed That means there is a randomness of the arrival of each photon and each detection event is independent of each other and independent of the already detected events The measurement accuracy generally increases with an increased number of detected photons but is limited by the photon noise op which is equal to the square root of the total amount of measured photons np o n 7 8 Thus if many measurements are done with a certain exposure time fp there will be a mean number of photons measured by a single detector element to The standard deviation of all single measurements is o ty to 7
49. semi volatile compounds contained in the PM may be removed from the filter The schematic diagram of the dehumidifier system by the dilution method is shown in Fig 3 22 A dilution method may use the dehumidifier system using the tube made of hygroscopic polymer membrane sulfone compounds with fluorinated polyolefin in the preparation of the pure dry air by the dehumidification In this case they should be exchanged in the same manner as the diffusion tube method after a fixed period passes 59 Manual for Air Concentration Monitoring Moreover since it is considered that the change in the dilution rate by pure dry air has a possibility to affect the concentration the dilution rate consistent with the setting value should be checked periodically When the data confirmation results in re adjustment the monitored values after the last maintenance should be verified and judged their adoption When those values are adopted as the reference value or accepted after the correction by using any correction equation it is always necessary to take note which explains the reliability of those values Sampling inlet PM particle size classifier Filter Flow controller Dehumidifier system controller Flow Solid line Flow of sampling air N Exhaust Dashed line Flow of pure dry air Figure 3 22 Dehumidifier system by the dilution method 3 1 4 4 Calibration of PM monitor The calibration of the PM monitor s
50. them in daily mean basis is less than 1 10 of the ambient air quality standard in each country Furthermore this parallel measurement shall be performed 2 Manual for Air Concentration Monitoring more than four times a year for grasping the seasonal variations 2 2 5 Air sampling method The sampled air flows as follows generally in the air concentration measurement system Sampling tube Filter Detector Flow controller Pump A sampling tube is a tube to take sample air into the monitor The material of a tube should be inert to measurement species and should not generate any gases disturbing measurement Furthermore a shorter length of sampling tube and a faster rate of sampling flow are recommended because adsorption and reaction on the objective wall are proportional to the residence time from the sampling inlet to the detector 1 Note of sampling tube The international standards such as ISO International Organization for Standardization or CEN European Committee for Standardization of the measurement of NO and O in the ambient air are defined Increase of NO gt concentration due to residence time in the analyzer or Calculation of residence times for a maximum allowable NO increase in the sampling line as the items for checking the performances The standard value is 2 or less and 4 ppb or less Detailed explanations are as follows As O is generally present in the sampled air a chan
51. triangular smoothing for all 1024 channels simultaneously 800 times The original spectrum was subsequently divided by its smoothed equivalent leaving only the narrow band spectral structures After applying the logarithm to prepare the spectra for the fit the corrected and filtered spectra were smoothed by the same triangular smoothing algorithm but only performed two times to even out noise structures This mechanism was used for both the corrected atmospheric and the lamp spectra as well as for all reference spectra Correction of fixed diode and Xe Lamp structures The fixed diode structures that proved to be highly variable were corrected by generating a reference spectrum for these structures a halogen lamp spectrum recorded together with the other reference spectra was high pass filtered by the algorithm described above including the logarithm and smoothing The resulting spectrum was used as the reference for the fixed diode structures For the correction of the Xe lamp spectra a linear fit of the diode structure reference spectrum and a polynomial of Sth order to the lamp spectrum were performed The residual of this fit represents a lamp reference spectrum that contains only the Xe lamp structure and is independent from fixed diode structures Correction of Fraunhofer structures An evaluation of the atmospheric stray light spectra yielded the result that significant Fraunhofer structures could be identified especially on the u
52. two different noise signals 1 Electronic noise due to the resolution of the digitalization the noise of the ADC and of other electronic components the electronic noise level can be determined by subtraction of two offset spectra from each other 2 Photon noise is another source of noise in a measured spectrum According to Poisson statistics the mean photon noise signal equals the square root of the number of photons 3 2 2 NO2 monitor As described above the LP DOAS system consists of a photodiode array detector coupled with a spectrometer a coaxial telescope a set of seven retroreflectors and an electronic control system A spectrometer a conventional czerney turner type with a holographically grooved grating blazed at 330 nm with 1200 grates mm was used to measure the trace gas species NO2 SO2 O3 and HONO in each respective ultraviolet UV region The instrument is periodically calibrated using the Hg emission spectrum The spectral resolution is less than 0 3 nm FWHM at around 334 nm To prepare the corresponding reference absorption cross sections the literature based absorption spectra were convoluted and interpolated with this instrumental function The concentration data of NO in the wavelength range 425 450nm are obtained sequentially by taking logarithms filtered and then followed with the non linear fitting of the absorption spectra for a set of measurements From the differential optical depth determined by
53. two spectra shown in the equation 3 18 D meas Ax In oA 1Y 3 18 the respective values c aj of ith species concentration and a coefficient of the polynomial of degree j are acquired by the following fitting process Platt 1994 which complies with the Beer Lambert law as shown below 68 Manual for Air Concentration Monitoring S Ak ly c o Da Residual 3 19 k i j Here o A denotes the differential cross section of the ith trace gas at the wavelength of the Ath pixel of the photodiode The residual term shown in the equation 3 19 is left after fitting to atmospheric spectra these residual term values then tend to vary within a few per mil o The residuals may stem from the combined effects of the following factors the atmospheric absorption of unidentified species the irremovable instrumental spectral patterns the detector state the statistical fit errors of the least square LSQ function and the erroneous matches of the measurement and reference spectra Therefore its structure has an important role in determining a lower detection limit DL 3 2 3 O3 monitor As well as NO2 O could be evaluated in the measured data by substituting the relative measurement reference with an absolute reference and including O in the fit between 276 and 288 nm Due to interferences in the DOAS retrieval it is not possible to obtain dependable O values at SO column densities above 2x10 molecules
54. 4 3 3 Procedures of the passive sampling Passive samplers take a variety of forms The procedure is explained for the sampling and analysis of Ogawa Passive method as follows Fig 4 5 and Table 4 5 show the construction and principles of Ogawa Passive sampler The apparatuses used on station and in laboratory are also shown in Table 4 6 106 Manual for Air Concentration Monitoring 1 Solid Pad 2 Pad Retaining Ring 3 Stainless Screen 4 Impregnated Filter 5 Stainless Screen 6 Diffuser End Cap with 25 holes to avoid turbulent diffusion n 14 23948 6 Diameter 2 cm Length 3 cm weight ca 10 g Figure 4 5 Construction of Ogawa Passive sampler Table 4 5 Principles of the Passive samplers Compound Regent for filters Analytical methods SO 10 TEA SO by IC O3 NaNO2 K2CO3 NO3 by IC NH3 Citric Acid NH by IC NO by Spectrophotometer NO2 10 TEA a NO7 by IC NO by Spectrophotometer NOx 10 TEA PTIO Ry NO7 by IC TEA Tri ethanol amine PTIO 2 Phenyl 1 4 4 5 5 tetramethlimidazoline 3 oxide 1 oxyl IC Ion Chromatograph Table 4 6 Apparatuses are used on station and in laboratory Station Laboratory Plastic glove Tweeze Plastic bag Plastic glove Plastic box Deionized water Field note Test tube NOx Shelter Plastic tube SO2 03 NO2 Cooler box Ultrasonic cleaner 107 Manual for Air Concentration Monitoring 1 Set up of samplers lt In laboratory gt The impregnate
55. 9 The signal to noise ratio therefore is S n p to n to A Z a aa 7 10 PS OS a om Now instead of using a single channel of the detectors chip and performing a large number of measurements one can also do only two measurements and use a whole bunch of neighboring channels for which the intensity does not change very much as statistically independent measurements To receive the signal to noise ratio of the two spectra and J they have to be divided channel wise This gives a ratio spectrum with values distributed around unity where all 148 Manual for Air Concentration Monitoring systematic differences between different channels are eliminated and only statistical variation remaining The observed standard deviation of J h is 1 to P J to i C n to n to O t V o Ta i n to Pa e e V2 ry V fn to Thus as a consequence of the channel wise division of the two spectra the standard 2 0 t 7 11 deviation increases by an additional factor of root 2 compared to the original relative standard deviation the original signal to noise ratio Plotting the observed a4 using the Root Mean Square RMS values of the divided spectrum on a double logarithmic scale we receive the following V2 1 1 logilo t log log2 logn 7 12 pe In t 2 2 p Thus the received straight line will have a slope of 1 2 To calculate th
56. ANET 2010 Also general monitoring requirement is followed by Guidelines for Acid Deposition Monitoring in East Asia EANET 2000 Manual for Air Concentration Monitoring The specifications of monitoring air concentrations and meteorological parameter described in this manual can be applied in the fundamental items for dry deposition flux estimation described in Technical Manual on Dry Deposition Flux Estimation in East Asia EANET 2010 Table 1 1 Relationship of monitoring items and described chapter Species Items Described Chapter SO Chapter 3 Chapter4 HNO Chapter 4 HCl Chapter 4 NH3 Chapter 4 NO NO2 NOx Chapter 3 Chapter4 O3 Chapter 3 Chapter4 PM Chapter 3 Particulate matter components Chapter 4 Meteorological parameters Chapter 3 References Acid Deposition Monitoring Network in East Asia 2000 Guidelines for Acid Deposition Monitoring in East Asia Network Center of EANET 25p Acid Deposition Monitoring Network in East Asia 2005 Strategy Paper for Future Direction of Dry Deposition Monitoring of EANET Second Edition Network Center of EANET 13p Acid Deposition Monitoring Network in East Asia 2010 Technical Manual for Wet Deposition Monitoring in East Asia 2010 Network Center of EANET 111p Acid Deposition Monitoring Network in East Asia 2010 Technical Manual on Dry Deposition Flux Estimation in East Asia Network Center of EANET 61p Manual for Air Concentration Mo
57. AS is the most popular one by using the artificial light source and is able to measure concentrations of gases at one dimensional scale up to several km The passive DOAS e g MAX DOAS uses natural light source without artificial light source and is able to measure concentrations 57 Manual for Air Concentration Monitoring of gases over two dimensional scales Topographic Target Light scattering Figure 3 23 Types of DOAS instruments 2 Absorption Spectroscopy Absorption spectroscopy uses the fact that every molecule when irradiated by electromagnetic radiation absorbs at distinct wavelengths These are directly linked to electronic vibrational and rotational states of the molecule that can be exited and therefore absorb radiation energy Fig 3 24 This process is described by the Lambert Beer law as shown in the equation 3 15 Remove by high pass filtering Lambert Beer s Law A 1 A ee 20 A e L Spire Ray eMie L A narrow wide band extinction es OPI SELARA REAS RRR na eee PRAA I E3 Mec ee eee eee eee eee eee eee Figure 3 24 Differential Optical Absorption Spectroscopy DOAS principle L I A 1 A an f ex 4 1 y 4 gt o 4 P T c o a 3 15 0 where A light intensity after passing through the atmosphere o A intensity of the light source A wavelength er A Rayleigh scattering coefficient ey A Mie scattering coefficient
58. Annular denuder 97 4 2 1 Introduction 97 4 2 2 Principle of annular denuder 98 4 2 3 Sampling procedure 100 4 2 4 Calculation of results 102 4 3 Passive sampler 103 4 3 1 Basic principles 103 4 3 2 Species specific information 105 4 3 3 Procedures of the passive sampling 106 4 3 4 Procedures of the chemical analysis 109 4 3 5 Calculation of concentration from collected amount 110 5 Maintenance 115 5 1 Standard operating procedures 115 5 2 Maintenance in a monitoring station 117 5 3 Maintenance of automatic monitors 118 5 3 1 Schedule of maintenance 119 5 3 2 Contents of maintenance
59. Environment Japan 2010 Ambient air continuous surveillance manual 6th Edition 366p in Japanese Environmental Resources Management 2007 Environmental monitoring and audit manual Environmental Protection Department Hong Kong 150p 125 Manual for Air Concentration Monitoring 6 Data reporting and validation The data are processed by the personnel in charge of the laboratory PCL the national QA QC managers NAM in each participating country and the network QA QC manager NEM The PCL has to collect the measurement data of air concentrations and meteorological parameters and input these data to the reporting format In addition other relevant information regarding dry deposition should be reported to NAM of each participating country The National Center and the NAM have to report monitoring data to the Network Center NC The NC and the NEM has to compile compute and verify the database of air concentration and provide a copy of the database to the participating countries when requested 6 1 Site specification The local circumstances information to be reported by individual country NAM are 1 the information which affects air concentrations such as specific meteorological data climate climate vegetation and life style 2 the information which affects measurement accuracy such as conditions of monitoring instruments laboratory conditions These data should be reported when there is a demand 1 Informati
60. MOLYCON is monitored by the J type thermocouple In the version 2 MOLYCON temperature is controlled by the temperature control board Fig 3 7 The neon lamp is lit when the MOLYCON is being heated up and flashes when the preset temperature 315 C is reached The thermocouple used is the K type Electronics MIXER BOARD Figure 3 8 Electronics Block Diagram Model 8840 Monitor Labs Inc One heater and thermistor are mounted on each reaction cell Fig 3 8 The reaction cells temperature controller on the mixer board keeps the temperature of the reaction cells at about 50 C The temperature effect is therefore eliminated Each reaction cell assembly houses a LED which is driven by the LED driver on the mixer board when the optic test is performed The photomultiplier tubes PMT transform the chemiluminescent emission into current The signal pre amplifier then converts the gt 78 Manual for Air Concentration Monitoring current into voltage The PMT temperature regulator together with the thermoelectric coolers and thermistor maintain the temperature of the PMTs at around 4 C to minimize the dark current effect The high voltage power supply board provides power around 900 V DC for the PMT The resistor network on the signal pre amplifier board provides a step down voltage for the driver circuitry on the mixer board which drives the analogue ammeter display when the HVPS test is perfo
61. NH3 18 04 NH4 Cair a X net Coo1 r net Cso F3 X Vsol V Air 1 a 10 M 2 netCgoi r means the net Cs of the F1 sample filter 96 Manual for Air Concentration Monitoring Chemical analysis of samples and blanks should be done each month in a lump When a blank value is detected as higher than the sample value the corresponded data should be regarded as non detected data N D If samples seem to be obviously contaminated the data should be treated as unrecorded data If sampling processes are stopped by any accident during sampling periods e g shutdown of electricity the samples obtained in these periods should be rejected because the filter packs absorb gases like passive samplers when they are in the breaks Ions balance R check can be considered for FO filter in the same way as described in Technical Manual for Wet Deposition Monitoring in East Asia 2010 EANET 2010 but if the organic acid or carbonate ions significantly exists in particulate matter the ions balance will be not good 4 1 7 Blank test and inter laboratory comparison It is recommended that 3 samples from each new batch of filters are analyzed as laboratory filter blanks The purpose of the filter blanks is to control the quality of the filters rather than to estimate the laboratory detection limit Normally the blank values should be sufficiently so low that their values can be ignored High blank values ma
62. PPER HOUSING Figure 3 6 Schematic diagram of the MOLYCON version 1 In order to measure the concentration of nitrogen dioxide NO2 in the air sample a molybdenum converter MOLYCON is used to convert nitrogen dioxide NO2 to nitric oxide NO The MOLYCON is kept at 315 C to maintain the following conversion process 3NO2 Mo gt 3NO MoO3 3 6 Oxygen in the air sample will also oxidize the molybdenum chips in the MOLYCON 302 2Mo gt 2M00 3 7 BOARD OUTLET FA eo ey 3 rd A MOLYBDENUM SEN Xi l eee CHIPS ENA Er Z X oOo Ste ity He a 3 z EXTERNAL en T K HOUSING i CON ys z a d INSULATING MATERIAL gt COPPER lt gt D ouswa Figure 3 7 Schematic diagram of the MOLYCON Version 2 2nF Manual for Air Concentration Monitoring The build up of molybdenum trioxide will lower the converter efficiency and the converter must be replaced when its efficiency drops below 96 Two versions of MOLYCON are currently installed in the NO NO monitor Model 8840 Monitor Labs Inc Their difference lies in the design of temperature control and the type of thermocouple used for temperature sensing In the version 1 MOLYCON a thermo switch is used to control the ON OFF state of the heater as indicated by the neon lamp on the front panel of the analyzer The operating temperature can be set by turning the temperature adjusting screw The temperature of the
63. RAT Grating spectrometer After the convolution all spectra were high pass filtered to remove all broad band spectral structures a triangular smoothing algorithm provided by the MFC software was applied to a copy of the original spectrum 800 times successively Subsequently the retained original spectrum was divided by the smoothed spectrum yielding a high pass filtered spectrum These spectra which contained only the narrow band absorption structures were used for the DOAS evaluation Fig 3 27 clarifies this process by the example of the NO cross section in the wavelength range of roughly 334 375 nm used for the evaluation of the long term measurements A variety of differential cross sections used for LP DOAS measurements is shown in Fig 3 28 Of special interest for this study are the cross sections of NO2 HONO l Manual for Air Concentration Monitoring HCHO O and Oy These cross sections are already convoluted to the typical resolution of the LP DOAS instrument and high pass filtered by the algorithm specified above 335 340 345 350 355 360 365 370 375 E S et a See Se a Se a Ge Ts ee Fat el eat eat eat NO absorption cross section 10 cm 335 340 345 350 355 360 365 370 375 Wavelength nm Figure 3 27 Effect of the high pass algorithm on the total absorption cross section panel A exemplified by the NO cross section The smoothed cross section panel B contains only the broad band structures
64. TAL ELECTRONICS REPEREN CE SAMPLE IN SOLENOID EXHAUST PUMP o BULKHEAD FITTING Figure 3 9 Schematic of operation principle 3J Manual for Air Concentration Monitoring The UV photometric ozone analyzer calibrator e g Model 49 49PS Thermo Fisher Scientific Inc determines the ozone concentration in the ambient air or from the internal ozonator by measuring the attenuation of light due to ozone in the absorption cell at a wavelength of 254 nm The concentration of ozone is related to the magnitude of the attenuation The reference gas passes into the absorption cell to establish a zero intensity reading 7o The solenoid then switches and the sample gas passes through the absorption cell to establish a sample light intensity reading The reference gas is generated by passing the sample through an ozone removing catalytic converter ozone scrubber The scrubbing element is manganese dioxide and the ozone in the sample is converted into oxygen The ratio of these two readings Jo is a measure of the light absorbed by ozone in the sample at 254 nm It is directly related to the concentration of ozone in the sample through the Beer Lambert law shown below Thee 3 11 where K Absorption coefficient 308 cm at 0 C 1 atmosphere and at 254 nm L Length of the cell in cm C Concentration in ppm A change in C of 1 ppb leads to a change in I I of 0 002 The source must be stable to better tha
65. Technical Manual for Air Concentration Monitoring in East Asia Endorsed by Scientific Advisory Committee of EANET at its Thirteenth Session Adopted by Intergovernmental Meeting of EANET at its Fifteenth Session December 2013 Network Center for EANET Table of Contents Preface 1 Introduction 1 1 Background 1 2 Objectives 1 3 Priority chemical species in EANET and mandatory metrological parameters nnn nnn nnn nn nn nn nnn nn nn nnn nnn nnn n nnn nnnnnnnnnnnnnnnnnnnnnnnnnne 1 4 Outline of the manual 2 Monitoring design 2 1 Siting criteria 2 2 Site facilities and Instrumentation Electricity Housing Air conditioning Inlet Data communication monitor arrangement etc 2 2 1 Design of monitoring station 2 2 2 Facilities 2 2 3 A
66. The 146 Manual for Air Concentration Monitoring measurement of precision should be done at least 4 times a year The accuracy can be determined as relative error between measuring results and setting values using standard filter The value of accuracy values should be checked at least once a year 7 6 2 DOAS 1 Determination of accuracy The errors of the DOAS measurements can be split into systematic instrumental and statistical errors The systematic error describes all errors caused by the recording of the spectra whereas the statistical error results from statistical processes like photon noise and the process of evaluation An overview of systematic errors is given below Beside absolute systematic errors concentration offsets the error is defined by the signal to noise ratio in the retrieved spectra The total noise consists of photon shot noise op the optical noise o Stutz and Platt 1997 and the instrumental noise o For good instruments the photon noise cp is the limiting factor in the signal to noise ratio In comparison to the other noise it is for sure pure statistical and can be reduced by accumulating more photons At a certain number of photons the photon noise will be so small that the other noise sources will dominate and the total noise will not further decrease with increasing number of registered photons or rather photo electrons This is the real limit for the best achievable measurement quality of
67. The narrow band differential absorption cross section o A plotted in row C is obtained by dividing the original by the smoothed spectrum i e row A B 62 Manual for Air Concentration Monitoring 250 300 350 400 450 600 650 detection AfostitisiitisiitiiiitiiyfAisiitisss limits 2 os 1 ppb 8 J L 5km 4 s We se 2 0 200 ppt L 5km 4 Jensa NO NO A D 100 ppt L 5km 5 ppt ASF WW L 5km 500 ppt L 5km N no ao L 12km 2 ppt L 12km _ ppt 16km 00 ppt 1km TN 50 ppt TN 0 Toluene T Jal para Cresol 200 100 Phenol Wavelength nm 0 ae ho 250 300 350 400 450 600 650 700 Figure 3 28 Differential absorption cross sections o A of selected atmospheric trace A x 3 0 ppt 1km T O I O s L aha LLa a a a ahata La adata aada PN mw 1 x 33 gases measurable by the DOAS technique For the calculation of the detection limits on the right side a minimum detectable optical density of 10 and the indicated light path lengths were assumed 4 Gas measurement by LP DOAS This presents the characteristics of the instrument the evaluation algorithm used for the evaluation of the spectra and a detailed estimation of the errors for the measured trace gas concentrations Fig 3 29 63 Manual for Air Concentration Monitoring Telescope reflector Spectrograph A Computer 5 ay Optical filter Figure 3 29 Schematic dr
68. akers Weight 30 g of K2CO and 10 g of glycerin in each 500 ml beaker Pour deionized water less than 0 15 mS m into each beaker and adjust to 500 g Mark the numbers No 1 No 2 and No 3 of the beakers for distinction 2 Dunk cellulose filters into No 1 beaker and stir them with a glass stick 3 Pull up the filter from the No 1 beaker using plastic tweezers dunk it in the No 2 beaker for the rinse 4 Pull up the filter from the No 2 beaker using plastic tweezers dunk it in the No 3 beaker for the rinse 5 Pull up the filter from the No 3 beaker using plastic tweezers and put the filter between two sheets of large cellulose sheet e g ADVANTEC No 590 Toyo Roshi Kaisha Ltd to absorb extra water from the impregnated filter 6 Keep the impregnated filter into a clean plastic filter case and seal it in a polyethylene bag with marking K CO3 7 Back to the step 2 for next filter But maximum 20 sheets could be prepared by one set of solution 93 Manual for Air Concentration Monitoring Recommended procedure of preparation of acid impregnated filter F3 is described as following steps 1 Prepare the mix solution 5 H3PO 4 2 glycerin Prepare three 500 ml beakers Weight 29 4 g of HPO and 10 g of glycerin in each 500 ml beaker Pour deionized water less than 0 15 mS m into each beaker and adjust to 500g Mark the numbers No 1 No 2 and No 3 of the beakers for distinction
69. al ozonator of the model 49 could also be used to calibrate other ozone 7 Manual for Air Concentration Monitoring analyzer Model 49PS REFERENCE SAMPLE SOLENOID SDE SOLENOID OZONATOR O BULKHEAD F NG Figure 3 13 Pneumatic path of the model 49PS Thermo Fisher Scientific Inc As shown in Fig 3 13 the pneumatic path of Model 49PS is similar to that of the model 49 excepts for the following 1 The photometers are used to measure the ozone from the ozonator which provides control feedback to maintain the preset concentration 2 Zero span solenoid valve and converter are absent and the reference gas is the zero air supplied by the external zero air supply An additional flow control regulator is present to ensure adequate reference gas flow The pressure regulator is normally set between 8 10 psig with at least 1 LPM from the internal zero air dump 3 The external zero air supply should be able to supply at least 6 8 SLPM of zero air at 20 psi Electronics The optical bench houses the lamp heater module with thermistor UV lamp 254 nm temperature transducer and two detector modules The source is a low pressure mercury vapor lamp with an expected lifetime in excess of one year Fig 3 14 The lamp is driven by a precisely regulated power supply with a square wave at about 15 kHz to ensure a high level of stability In order to achieve the highest level of stability of light output the lamp itself
70. and measuring projection latitude longitude and time 3 Maintenance protocol Since the sensing part of the wind direction anemometer is installed in the outside and it always runs continuously the maintenance of a meteorological instrument is also important for measurement accuracy as well as the maintenance of a monitoring station _75 Manual for Air Concentration Monitoring The maintenance consists of the daily check for checking normal operation of meteorological instruments and periodical check for maintaining measurement accuracy 1 Daily check i The existence of abnormalities is visually checked for the appearance of the transmitter ii Abnormalities of directions and record are checked iii There is no gap between the indicated value of anemometer and a compass iv Input signal cable is removed and the zero signal of wind velocity is checked 2 Periodical check Usually periodical check is implemented by the maintenance contractor It is necessary to conduct not only the comparability test with the standard conversion output but also the performance test of external outputs such as indicated values record values and telemeter output 3 3 3 Thermometer Air temperature is greatly changed by time the place and the height In particular the difference from the state of surface such as a concrete ground a bare ground and a grass ground and the temperature gradient around the ground may largely affec
71. and requires good control of chemical analyzes and particularly of blank values The sampling setup is relatively simple but needs to be defined in relation to the sampling site and practical arrangements in connection with transport of unexposed denuder sampling trains and filter packs The recommended denuder tubes are both expensive and brittle The simple tubular denuder systems require much less expensive equipment If blank values including field blanks and chemical analyzes can be controlled this system can be adopted as the alternative to the above described system 4 2 3 Sampling procedure 1 Preparation of the sampling unit The preparation and coating of the denuders should take place in the laboratory that will carry out the chemical analyzes of the collected samples The denuders have to be thoroughly cleaned preferably by immersion in strong detergent for several hours and then rinsed in deionized water For collection of HNO3 D1 a solution of 9 NaCl and 1 glycerol is prepared by dissolving in 100 ml of 50 50 v v methanol water solution For collection of acidic gases D2 a solution of 1 NaCO and 1 glycerol is prepared by dissolving 1 g of the analytical grade reagents in 50 ml of deionized water and then diluting to 100 ml with methanol Similarly for collection of NH3 D3 1 g of citric acid or oxalic or phosphorous acid is dissolved in 50 ml of deionized water and then diluted to 100 ml with methanol For the
72. ar radiation the comparison test should be conducted on a cloudy day v Since water may go into a vent sleeve and an obstacle may appear in measurement when strong wind and rain occur it is cautious of data 2 Periodical check i The signal cable is disconnected from the input terminal of converter and the resistance of the sensor is measured to confirm the prescribed value ii It is necessary to apply the pseudo resistance to thermometer and conduct the performance test for external outputs such as indicated values record values and a telemeter outputs Usually this periodical check is implemented by the maintenance contractor Erge Manual for Air Concentration Monitoring 3 3 4 Hygrometer There are some parameters indicating the water vapor contents in the air such as relative humidity absolute humidity vapor pressure and dew point but relative humidity is most widely used Although a hair hygrometer and a dew point hygrometer was used formerly but an electrostatic capacity type hygrometer is widely used in the air monitoring because it can be installed together with a thermometer in the same vent sleeve 1 1 Relative humidity Relative humidity is expressed the ratio of vapor pressure e and the saturated vapor pressure at the measured temperature E with the percentage of e EX 100 It is represented by an integer with an unit of 2 Vapor pressure The vapor pressure is defined as the partial pressur
73. at 2000 O cross section convoluted from Voigt et al 2001 Og cross section interpolated from Hermans et al 1999 SO cross section convoluted from Vandaele et al 1994 Fraunhofer spectrum Corrected lamp structure spectrum O ON DN BW NY Fixed diode structure spectrum The references 2 3 5 and 7 were linked to the shift and squeeze parameters obtained from the non linear NO fit to exclude arbitrary shifting and squeezing due to small absorption structures For the O reference permitting a shift or squeeze decreased the quality of the fit and was therefore denied The correct wavelength scale calibration for the NO and HCHO references was deduced from reference cell measurements This was not possible for HONO and O due to the lack of suitable reference gas cells but for both trace gasses no significant shift versus the NO2 reference could be observed The diode structures were fitted without permitting a shift or squeeze because no shift or squeeze is expected due to the nature of these structures For each evaluated spectrum the residual was saved to disk and added to the residuals of the spectra evaluated before After a first run of the evaluation algorithm residuals featuring a delta above 5 o which hints on the occurrence of an error within the fit were removed from the sum of all residuals The resulting spectrum is used as an additional ninth reference for a second run of the evaluation The justification f
74. ater F2 alkaline imp filter Extraction with 10 ml deionized water with H202 3 F3 oxalic acid filter Extraction with 10 ml deionized water 101 Manual for Air Concentration Monitoring Unscrew the cap at one end of the denuder to be extracted add exactly 10 ml of the extraction solution with a pipette put on the cap and shake the denuder and then transfer the extract to a stoppered test tube for subsequent analysis It is essential to work quickly in order to minimize contamination The filters may be folded and transferred to the same kind of stoppered test tubes to which 20 ml of extraction solution is added The tubes are shaken by a shaker or an ultrasonic bath during 20 minutes Chemical analyzes of the extracts are to be made as follows shown in Table 4 4 In the same way as filter pack ion chromatography IC is recommended for analysis of the above mentioned chemical components The analytical method should follow the procedures described by Technical Manual for Wet Deposition Monitoring in East Asia 2010 EANET 2010 Table 4 4 Chemical analysis of the extracts from denuder and filter pack lons to be determined Analysis methods NO3 N S04 S CF NOZ N lon chromatography Section 4 NO3 N SO S CF NO7 N lon chromatography Section 4 NH4 N Spectrophotometry or Section 4 ion chromatography NO3 N S047 S NH4 N CI lon chromatography and Section 4 NO7 N spectrophotometry NO3 N S047 S
75. atively it is essential that the transport occurs solely by molecular diffusion and that no gas is lost on the walls of the sampler Under these conditions then the sampling rate the concentration range of the sampler is directly proportional to its cross sectional area and inversely proportional to its length Furthermore since the rate of molecular diffusion depends on temperature through the temperature dependency of the molecular diffusivity the average sampling rate sorbed amount per unit time divided by the ambient concentration is a temperature dependent constant for the given species and the type of sampler Care must be taken to ensure that the gas is transported to the filter by molecular diffusion If the inlet end of the tube is left open then convective transport can occur resulting in a higher sampling rate and thereby an overestimation of the concentrations Ohizumi et al 2013 It was showed that covering the inlet region of the sampler with a fine mesh e g stainless steel mesh with a thread diameter of 0 08 mm and mesh aperture of 0 125 mm can minimize these errors for high dose samplers Ohizumi et al 2013 Low dose samplers are more sensitive to wind effects and porous membranes supported by steel mesh are commonly used to cover the sample inlet Ohizumi et al 2013 The accuracy of a diffusion sampler depends critically on the collection efficiency of the impregnated filter A solid and stable reagent which sele
76. avity Attenuated Phase Shift Spectroscopy Environmental Science and Technology 42 6040 6045 Ministry of the Environment Japan 2010 Ambient air continuous surveillance manual 6th Edition 366p in Japanese U S Environmental Protection Agency 1997 Revised Requirements for Designation of Reference and Equivalent Methods for PM and Ambient Air Quality Surveillance for Particulate Matter Final Rule 40 CFR part 58 Federal Register 62 138 38830 38854 155 gt Printed by Network Center for EANET Asia Center for Air Pollution Research 1182 Sowa Nishi ku Niigata shi 950 2144 Japan http www eanet asia http www acap asia
77. awing of the LP DOAS system The LP DOAS system is made up of main three parts the light source telescope and retro reflector and detection unit The HMT DOAS The DOAS system presented here is developed in close cooperation with Hoffmann Me technik HMT Rauenberg Germany and it will therefore be referred to as HMT DOAS In the following the components of this system will be discussed in detail Light source The light source used for the LP DOAS system is high pressure Xenon Xe arc lamps as they are commercially available Xe short arc lamps are point light sources providing high luminance and color temperature They emit a continuous spectrum of light ranging from UV through visible to infrared A high voltage ignition discharge plasmasizes the Xe gas and produces a light arc of approximately 1 mm diameter between the anode and the cathode The typical spectrum of the Xe arc lamp is the superposition of the thermal emission according to Max Planck s law and single Xe emission lines Under operating conditions the Xe gas is under high pressure of up to 100 bar in the lamp body Therefore the atomic emission lines are broadened by pressure and temperature The color temperature of the lamps is approximately 6000 K which is similar to that of the sun A high local light intensity and a small divergence of the emitted light beam can be attained because the small distance of the electrodes results in a small arc length As the Xe lamp b
78. bsorption to the tube A net may be installed to prevent penetration of small insects to the sampling inlet As for PM sampling it is desired to be small the loss of particle in the sample air which is introduced to a particle size classifier Moreover it is also desired to have the structure avoiding rainstorm and foreign substances like insect To attach raindrop collector which can intercept the penetrated raindrop before reaching to the particle size classifier is recommended Furthermore the maximum length between the particle collector detecting element and the sampling inlet shall be 5 m or less and the maximum length between the particle collector detecting element and the exit of particle size classifier shall be less than 1 5 m The sampling inlet and the particle collector detecting element shall be present on the vertical line and the sampling tube must not have a bend section For this reason when the PM monitor is installed inside the station the sampling tube shall be placed through the ceiling of the station 2 Manifold method This is a method that makes the air flow into the station from the sampling inlet by a blower turbo fan etc collectively and distributes to each monitor This method is used for the gaseous pollutants when the distance between the sampling inlet and the monitor is more than 5 m because this method can reduce the residence time of the gaseous pollutants in the sampling tube due to forcible sucti
79. c knowledge the periodical check should be conducted by the maintenance contractor It is necessary to carry out not only the comparability test for sensor and signal converter but also the test for external outputs such as indicated values record values and telemeter outputs 3 3 5 Actinometer The solar radiation is defined as the quantity of the solar energy irradiated into the plane per unit area near the ground Because the solar radiation largely affected by water vapor dust and cloud it is evaluated as integrated amounts during a certain period The unit of solar radiation is kW m for the instantaneous value and MJ m for integrated value 79 Manual for Air Concentration Monitoring 1 Direct solar radiation The direct solar radiation is defined as the amounts of solar radiation directly transmitted from the sun It can be measured during sunrise and sunset Supposing the atmosphere does not exist in the earth the direct radiation from the sun would be almost constant because it is determined only by solar activity and the distance from the sun This amount so called the Solar constant is 1 38 kW m for the instantaneous value and 5 0 MJ m for the integrated value 2 Global solar radiation The global solar radiation is defined as total solar radiation irradiated into the plane per unit area The global solar radiation includes direct solar radiation the dispersion solar radiation from all sky and the reflective so
80. ccount In addition as the large systematic error might be produced if the span coefficient is changed without noticing dirt and crack of an equivalent film and thus one must take extra care for the equivalent film It is also effective to check by using two or more equivalent films 54 2 Manual for Air Concentration Monitoring Moreover some cracks and dirt are attached on the film in many cases during repeating use so the film is recommended to be renewed at that time Dynamic sensitivity check The PM monitor is operated for sample air simultaneously with the low volume air sampler method which is the standard method FRM and three or more data sets should be obtained in the period of 2 or 3 days For those data sets it is confirmed that the differences between the measured value and the value of standard method are within 10 pg m or 10 When the difference does not exceed the criteria but the monitored value shows systematically low in comparison with the value of the standard method any loss due to the sampling tube should be checked and improved if needed The following points should be cared in the implementation of the dynamic sensitivity check i When selecting a position in which the low volume air sampler is set the position of the sampling inlet should be determined carefully to minimize the difference of concentrations between the PM monitor and the sampler ii Regarding the sample collection filte
81. cipitation 1 4 Outline of the manual This technical manual provides a comprehensive guideline for air concentration monitoring in EANET countries in order to standardize air concentration monitoring and provide comparable data at EANET monitoring sites The manual composed of 8 chapters First feasible automatic monitoring of gaseous species and aerosol mass concentration was described Since aerosol composition monitoring is feasible only by manual monitoring its specifications were described Furthermore other necessary requirement was described in the latter part Table 1 1 shows the relationship of monitoring items and described chapter Chapter 1 provides general background and the objective of the preparation of this technical manual Manual for Air Concentration Monitoring Chapter 2 describes monitoring design such as siting criteria site facilities and instrumentation at a monitoring station and monitoring frequency for each monitoring item Chapter 3 describes a guideline for automatic monitoring of gaseous species particulate matter and meteorological parameter This chapter covers specification of automatic monitors and calibration procedures Specifications of air concentration monitors cover both point measurements and long path measurements Chapter 4 describes a guideline for manual monitoring of filterpack and passive sampler which are widely used for EANET monitoring Furthermore a monitoring guideline of ann
82. controlling unit could be also acceptable In this case the gas volume meters should be installed consequently after the pump to measure flow rates and volumes under the condition of atmospheric pressure Example C and D in Fig 4 2 Air volume measured by a mass flow meter or a gas volume meter is used for calculation of ambient air concentration Accurate volume reading is important for the measurement accuracy and the volume meter may require frequent calibrations Unless special circumstances calibration of the gas volume meters should be implemented once a year The accuracy must be better than 5 If the pump and gas meter is kept at room temperature no corrections are usually required and the air volume is then assumed to be the sample air volume at 20 C If deviations of more than 5 C are expected the temperature in the gas meter surroundings has to be recorded and the air volume corrected accordingly 3 Sampling procedure At the site and before the filter pack is mounted in the sampling line the site operator has to record the start date and time of the sampling and likewise the end date of time the sampling after exposure Further details should be written into the field note if operator find special notes that may affect the monitoring results Recommended sampling procedure at the monitoring site is described as follows At start 1 Read the indicated value of the volume meter before sampling and record it in the field not
83. ctively and quantitatively chemisorbs the targeted species and transforms it into another stable form in which other pollutants do not interfere is necessary for passive samplers This is the key factor which determines which species are suitable for passive sampling The average concentration at the measurement site over the time period that the sampler is exposed to ambient conditions is determined by chemical analysis of the filter Analysis consists of removing the impregnated filter and extracting the reaction product typically using deionized water The extract is then analyzed using an appropriate analytical technique The measurable highest concentration depends on the amount of sorbent on the impregnated filter This is typically estimated by the stoichiometric amount of the impregnate 104 Manual for Air Concentration Monitoring reduced by a safety factor typically a factor of 2 The lower detection limit of the samplers is determined by the use of blanks As soon as a filter is impregnated it will begin to measure ambient levels A filter kept in the laboratory will measure laboratory blank while field blank will measure the integrated exposure during the transport and storage periods The filters should be impregnated just before the samplers are sent to the field Some filters are labeled as the field blank and the others are analyzed immediately and those filters are identified for laboratory and field blanks The laborator
84. d be kept in the marked and dated plastic bags Each of the filter cases should be sealed one by one into a polyethylene bag Furthermore they should be placed into aluminum coated bag After the sealing they should be kept in the refrigerator The bags filled with impregnated filters should be stored in desiccators alkaline impregnated filters in one desiccator and acid impregnated ones in another one The desiccator for alkaline impregnated filter should have citric acid at the bottom and the one for acid impregnated filter should have KOH at the bottom Impregnated filters should not be stored more than 3 months before use All quality assurance steps and results should be recorded in the laboratory journal _94 Manual for Air Concentration Monitoring 3 Extraction and chemical analysis Extractions and chemical analysis of the sample and blank filters stored in a laboratory should be carried out at the same time For the extractions the sample shakings should be done by using a shaker or an ultrasonic bath during 20 minutes Chemical analysis should be carried out each month in a lump but as soon as possible after the extractions Analyzed species and solvent for each stage are shown in Table 4 2 Table 4 2 Analyzed species and solvent for each stage filter Stage Species Solvent First FO SOx NO3 Cl NH4 Na K Ca Deionized water Mg Second F1 S04 NO37 Cl NH4 Deionized wate
85. d filters should be packed in a polyethylene bag and the polyethylene bag should be stored in freezer In one use commercial filters there are typically 20 impregnated filters in a pack 2 impregnated filters will be set to a sample holder of the respective pollutants for each sampling period by using clean tweezers and plastic gloves Four kinds of samplers are prepared for each sampling period The samplers should be stored in sealed plastic bag box The samplers should be shipped to the station by using a cooler bag box to avoid deposition of the ambient gas lt On Station gt Take out new samplers from the plastic bag box by using plastic gloves and then install it in the shelter Write following information in the field note The sampling period is between 1 week to 1 month Start date of the measurement period dd mm yyyy e g 29 11 2006 Start time of the sampling hh mm e g 10 10 AM Name of reporter Notes e g Strong wind 2 Recovery of samplers lt On Station gt Remove the samplers from the shelter and pack them in plastic bags box Ship the samplers to the laboratory by using a cooler bag box Write following information on the field note End date of the measurement period dd mm yyyy e g 29 11 2006 End time of the sampling hh mm e g 10 10 AM Name of reporter Notes e g Strong wind lt In laboratory gt Extraction of filter Remove exposed filters from samplers and put them
86. d on the pollutants to be monitored the monitoring objectives proximity to other monitoring stations and operational efficiency The EANET has developed siting requirements for wet deposition monitoring in East Asia These requirements include distance from trees buildings and roadways distance from major point sources Other factors should be included site security and access availability of electricity and telephone service aesthetics and local zoning issues and long term more than 10 years site availability Unfortunately the ideal monitoring site is virtually impossible to acquire especially in urban areas 2 1 Siting criteria Air concentration dry deposition monitoring sites are classified into three categories remote sites rural sites and urban sites according to the objectives of the monitoring a Remote sites Remote sites are to be established for the assessment of the state of air quality in background areas The monitoring data can be used to evaluate long range transport and f Manual for Air Concentration Monitoring transmission models of air pollutants in East Asia The location of these sites should be selected in areas with no or least influence from local emission and contamination sources Therefore remote sites should be located with sufficient distance from significant stationary sources such as urban areas thermal power plants large factories and significant mobile sources such as major highways
87. del and manufacturer of the monitors kind of calibration gas calibration methods calibration frequency shapes of a manifold or a sample inlet tubing air condition status in the monitoring station Start and end times of sample collection in the sampling plan should be also reported Pictures of collector and design diagrams should be attached Filter pack instrument The following should be reported model and manufacturer of a filterpack suction pump and a flow meter model and manufacturer of other manual monitoring equipment if applicable calibration method of flow rate arrangement of instrument components tubing air condition status in the monitoring station Start and end times of sample collection in the sampling plan should be also reported Pictures of collector and design diagrams should be attached Meteorological instruments The following should be reported model and manufacturer of the instruments maintenance records arrangement of the instruments in the site and monitoring frequency duration interval Pictures of collector and design diagrams should be attached 3 Sample history Sample history plays an important role in sample handling from collection to chemical analysis of the filter pack samples Shipping Shipping frequency and packing procedure for collected samples should be also reported Laboratory operation The following should be reported sample preparation procedure plan of chemica
88. dical check may increase than usual because many instrumental problems may be raised especially after standard life time However the periodical check cannot cover the comprehensive maintenance and repair because of limitation of available instrumental parts checking l22 gt Manual for Air Concentration Monitoring times and skilled staffs An overhaul is carried out when it needs to keep the good precision of the instruments and the period check is insufficient In the overhaul the manufacturers bring their instruments in the factory The instrument will be disassembled and the performance of each part is checked After the replacement of necessary parts the instruments will be assembled again Finally the operation test is performed for a fixed period and the overall performance is checked Because the comprehensive facilities are required for overhaul and the instruments must be temporally removed from the station overhaul should be conducted if serious instrumental problems are not resolved and the periodical check cannot improve measurement precisions Moreover the alternative instruments should be installed when the overhaul is conducted 5 4 Field record All monitoring sites should essentially satisfy the siting criteria If there are some differences from the criteria they should be documented and evaluated for integrity and validity of the monitoring data Any significant changes around sampling sites and conditions should
89. e 2 Remove the exclusive cap from the new unexposed filter pack and mount the holder in the sampling system 3 Switch the pump on and record the starting date and time and the flow rate in the field note At end 4 Record the flow rate in the field note 5 Switch the pump off and record the ending date and time in the field note 90 Manual for Air Concentration Monitoring 6 Dismount the filter pack holder from the sampling system put the exclusive cap on and then seal it into a polyethylene bag and an aluminum coated bag 7 Keep the sealed holder in the transportation box with coolant 8 Read the indicated value of the volume meter after sampling and record it in the field note 4 1 5 Operation in laboratory 1 Mounting and transportation of filter packs It is recommended that the filter pack is assembled and dismounted only in the laboratory The filters are mounted on the filter holder using clean plastic tweezers When assembling the filter pack the parts should be tightened at the torque specified by the manufacturer to prevent leaks The leak of air through stage connections should be checked using a flow meter with a pump every time Fig 4 3 If the rotameter shows 0 liter min or the needle of the gas volume meter stops moving while the inlet of the filter pack is attached with the rubber sheet and air is drawn by a pump it will be confirmed the filter pack has no leak It is recommended to open a 3 way valve slowl
90. e http www city yokohama lg jp kankyo mamoru kenkyu shiryo pub d0001 d0001 pdf 114 Manual for Air Concentration Monitoring 5 Maintenance 5 1 Standard operating procedures SOPs are written procedures used in all the processes of the monitoring system i e in the field laboratory and for data management SOPs provide a method designed to ensure that all personnel follow the same procedures in an identical manner minimizing the variance of data quality between individuals ensuring each person conducts their works with a scientifically sound understanding of QA QC Each of the sampling and chemical analysis organizations or laboratories should ensure that the SOPs meet the requirements of their respective organizations and that the SOPs comply with the Technical Manuals and the national QA QC programs in EANET The SOPs need to be straight forward and sufficiently clear to ensure that beginners can perform the tasks in an effective manner The SOPs are to be updated in a timely manner and should take into consideration changes in technology and advances in science Essential components of the SOPs are outlined as shown below 1 Monitoring 1 1 Appointment of monitoring staff and their supervisors 1 2 Check of possible changes around the monitoring sites 1 Local situation new construction of emission and contamination sources etc 2 On site situation 1 3 Check of monitoring instruments 1 Appearance of instruments check for
91. e Another source of error could be that the absorption of sulfur dioxide on the impregnated filter is not 100 effective It may be possible to lose components before the analysis due to incomplete extraction from the filter Since the filter pack method cannot separate gaseous nitrogen compounds from aerosols only the sum can be given In other words the concentration of nitrates in air equals the sum of the nitrate found on the aerosol filter and nitrate found on the alkaline impregnated filter The same for ammonium where the sum of ammonium concentration equals the sum of ammonium collected on the aerosol front filter and ammonia collected on the acid impregnated filter Nitric acid in the gaseous state readily reacts with other atmospheric constituents to form nitrates in the form of atmospheric particles If ammonium nitrate is formed the reaction is reversible and its presence requires a dissociation product of gaseous nitric acid and ammonia which in turn depends on temperature and relative humidity The mechanisms of artifacts are based on the reactions as follows 1 Artifacts of HNO3 I NH NO P gt NH G HNO G II NH4NO P H2SO0 P NHsHSO P HNO G II NaNO P H2SO P NaHSO P HNO G IV NaCl P HNO G gt NaNO P HCI G 2 Artifacts of NH3 I NH4NO P NH G HNO G Il NH Cl P NH G HCI G Ill HS0 P NH G gt NH HSO P IV NH4HSO
92. e NH4 NO and Cl monitoring and the denuder can measure gases and particulate components separately These methodologies are used widely in monitoring networks and for field campaigns in the world The advantage of filter pack is to simultaneously determine gases and chemical components in particulate matter although the problem of artifacts mentioned in 4 1 2 is remaining as agenda Annular denuder can also determine gases and chemical components in particulate matter simultaneously without artifacts on the other hand the disadvantage of annular denuder is complication of handling and relatively high cost compared with filter pack 4 1 Filter pack A multiple filter pack method can provide significant information such as the concentration of chemical species in particulate matter and gaseous compounds including ammonia and nitric acid Karakas and Tuncel 1997 The monitoring using filter pack method has been widely conducted all over the world Aikawa et al 2005 2006 2008 2010 Endo et al 2011 Mehlmann and Warneck 1995 T rseth et al 1999 Kim et al 2001 Matsuda et al 2001 Viet et al 2001 Among the air concentration monitoring methods the filter pack method has been adopted for the dry deposition monitoring programs in CASTNet US CAPMoN Canada and EMEP Europe EANET also has experiences to carry out monitoring using the filter pack methods for longtime 4 1 1 Principle of using filter pack The four s
93. e specific condition for the filter pack instrument to estimate dry deposition flux In the case of any close obstacles in the surrounding of the monitoring site such as forest trees the inlet should be set up higher than 3 meters above the ground if possible over the top of the obstacles e g above tree canopies Since the absorption of sulfur dioxide is only quantitative at relative humidity above 30 sampling with a filter pack should take place outdoor only sheltered from the ambient air by the air inlet Additions of glycerol may improve the absorption efficiency of the impregnated filter at low humidity Maintenance of equipment should be performed in accordance with their instructions for operation of field instruments such as pumps flow meters and gas volume meters Calibration of the flow meters and the gas volume meters should be done at least once 88 Manual for Air Concentration Monitoring every year using the national standard method The leak check of the sampling system should be done more than twice a year 2 Flow rate The flow rate of 1 liter min is recommended for weekly or biweekly sampling If it would be difficult to detect concentrations in remote sites flow rates could be increased up to 2 liter min Typical flow rate for daily sampling is around 15 liter min Open face inlet should be recommended in the case of weekly or biweekly sampling If specific devices are utilized for removing large particles in
94. e PM monitor or the sampling inlet of PM is installed on the roof of the station it is necessary to decide the height of sampling inlet in order to prevent the influence on the roof or winding up the sand on the roof Taking into account the above information as well as to decrease the contamination from the ground and to increase the regional representativeness of the site this manual recommends to monitor SO NO2 NO O and PM at the height of 3 0 10 m above ground Additionally it is also recommended the sampling inlet should be located at the position higher than the roof of the station building If it is impossible the inlet should be located at the position keeping distance 2 0 3 0 m or more from the wall of the station building In the same meaning when the monitoring is implemented in a forest area the sampling inlet should be set at the position higher than the top of canopy or keeping enough horizontal distance from the trees If it is impossible to install the sampling inlet based on the manner described above or it is not appropriate to follow the manner described above by unavoidable reasons such as difficulty of ensuring land for the station etc it is required to install the sampling inlet as follows i The height of sampling inlet shall not exceed 30 m above ground ii Parallel measurement shall be done with the neighborhood site which follows the manner described above It is necessary that the difference between
95. e and then analyzed by IC or spectrophotometry NO2 measurements using this impregnation method in an active filter mode have been compared to those using a automatic NOx analyzer 3 NH3 Citric acid is used to impregnate the NH samplers The NH in the exposed filters is analyzed by IC The concentration range of a short passive sampler is 0 1 15 ppb 0 2 30 ppb for monthly sampling The performance of the passive samplers for ammonia was found not to be as good as that for SO2 and NO2 WMO GAW 1997 The repeatability was improved after replacing the inlet screen with a solid cap after sampling to minimize volatilization with a solid phase which deposits on the inlet screen WMO GAW 1997 4 O3 NaNO is used to impregnate the O3 samplers O oxidizes nitrite to produce nitrate Because the converted amounts of nitrate is stoichiometrically equal to the sampled O3 ozone concentration is determined by the nitrate concentration in extract by using IC This monitoring is widely used in global network such as WMO WMO GAW 1997 and it is suitable to monitoring AOT40 in mountainous area where electricity is hard to obtain However the previous study showed that in the case of higher wind speed gt 5 m s condition O3 concentration measured by a passive sampler is underestimated when it was compared with the automatic monitor results Therefore meteorological condition should be considered for O3 monitoring Ohizumi et al 2013
96. e correct signal to noise ration from the divided spectrum we have to multiply by the factor of root 2 Thus one obtains s on A oe og Fy F C 7 13 h By increasing scans and thus observed photons the photon noise can in principle be reduced unlimited But in reality from the total noise mainly the photo noise is reduced and thus at a certain scan number the total noise will not further decrease as it is then dominated by the instrument noise It is important to determine at which noise level and after how many scans this level is reached To perform more scans during a measurement is useless and will only reduce the temporal resolution but not increase the signal quality Since for DOAS measurements and data evaluation the noise is displayed in the residuum spectrum for simplicity in the noise test we take into account only the standard deviation and not the signal to noise ratio This makes it easier to compare the achieved values in the noise test with those of measurements DOAS monitoring only focuses on narrow band absorption structures all broad band variations will be ignored 149 Manual for Air Concentration Monitoring 3 Optical Noise co Optical noise can arise from all optical components First of all the light source can be unstable in the spectral characteristic or intensity For example a spectral change of the used xenon arc lamp or even a halogen lamp is not necessarily spectrally stable For the no
97. e in the air The saturated vapor pressure is defined as the pressure in the state of thermodynamic equilibrium between the water or ice phase and the air at a certain temperature The unit of vapor pressure is hPa and it is recorded up to 0 1 digits 3 Dew point If the air is cooled under the constant pressure the water vapor will be saturated at a certain temperature and then water condensation and dew formation occur The temperature is called the dew point temperature with an unit of degree and to be recorded up to 0 1 digits Principle of measurement 1 Electrostatic capacity type hygrometer Change in the dielectric constant by moisture absorption of a polymer thin film is converted to the frequency change in an oscillating circuit and the change is outputted as relative humidity 2 Dew point type hygrometer Due to the hygroscopicity of a lithium chloride LiCl there is a relationship between the LiCl solution and vapor pressure The dew point is measured by the temperature when the ambient vapor pressure is equal to the saturated vapor pressure of LiCl solution However there is restriction that the dew point cannot be measured below the ambient pressure 3 Hair hygrometer When the humidity in the air changes a hair stretches depending on humidity Because the extension rate of hair varies almost logarithmically with the relative humidity between 20 to 100 the relative humidity can be determined ETR Manual for Air Concent
98. e loss of ozone NO2 O3 o 03 2 2 By assuming certain concentrations for O3 and NO and a certain residence time the increase of NO can be calculated and compared to the NO level already present Example Taking the following values Os 22 nmol mol NO 100 nmol mol b 78 nmol mol b Ozh NO k 4 43x10 nmol mol s at 25 C t 2 seconds result in the ozone concentration at the sampling inlet O3 o of 24 1 nmol mol The increase in NO is 24 1 22 2 1 nmol mol Assuming that the level of NO at the sampling inlet equals to the level of NO at the sampling inlet the increase of NO equals 2 1 100 2 1 x100 2 2 Structure of sampling tube There are two methods for sampling air individual sampling method and the manifold method The structures and usage notes are indicated as follows 1 Individual sampling method This is the method that each monitor has a sampling tube individually The method is generally applied when the sampling inlet to the monitor is less than 5 m in length since adsorption on the surface of the sampling tube induces a problem in the case of a gaseous pollutant The tip of the sampling tube is attached with a funnel and bent below for preventing rainfall etc In addition the extreme bending of the tube should be avoided In the case of PM the individual sampling method is recommended to prevent fay Manual for Air Concentration Monitoring the a
99. e on line errors Data treatment system abnormal initial data and problems of data treatment equipment Others influence of temporary local emissions etc Certain should be established to decide whether the data can be used as they are or after adjustment or cannot be used The criteria for non usable data are established to judge whether some abnormal hourly data are within the allowable range of data reliability or could be adjusted in principle These criteria should be established taking into account the present state of arts technologies and the objectives of the measurements For instance the criteria for non usable data in Japan are presented below Ministry of the Environment Japan 2010 Criteria for non usable data in Japan SO Span of the instrument Lower limit within 4 of the pre determined value Upper limit within 10 of the pre determined value Zero value of the instrument Lower limit within 2 of the maximum scale value Upper limit within 4 of the maximum scale value 141 Manual for Air Concentration Monitoring NO NO2 NOx Span of the instrument Lower limit within 4 of the pre determined value Upper limit within 10 of the pre determined value Zero value of the instrument Lower limit within 2 of the maximum scale value Upper limit within 4 of the maximum scale value Os Span of the instrument Lower limit within 4 of the pre determined value Upper limit within 10
100. eaction cells namely the NO and the NOx cell In the NO cell nitric oxide NO in the air sample reacts with ozone 03 from the ozone generator to form excited nitrogen dioxide NO2 molecules Light emission with a maximum intensity at approximately 1100 nm results when the excited NO molecules decay to lower energy states This phenomenon is known as chemiluminescence and the chemical equation is shown as follows NO O gt NO2 O2 hv 3 3 Since one NO molecule is required to form one NO molecule the chemiluminescent emission intensity is proportional to the NO concentration in the air sample The ozone required for the above reaction is generated when a steady stream of dry air is ionized by the discharge of a high voltage 7500 V rms electrode a5 Manual for Air Concentration Monitoring 302 gt 203 3 4 Dry air is needed to avoid acid formation and thus contamination of the pneumatic path and ozone generation shown as the equation 3 4 The nitrogen dioxide NO2 in the air sample is converted to nitric oxide NO by a molybdenum converter MOLYCON before it enters the NOx reaction cell This MOLYCON is heated to approximately 315 C for the following reaction to take place 3NO2 Mo gt 3NO MoO 3 5 Chemiluminescence reaction also takes place in the NOx cell and the intensity of radiation is then directly proportional to the total nitrogen oxides NOx concentration i e NO NO in the ambien
101. ecific procedure one must refer and follow the instruction d Manual for Air Concentration Monitoring 3 1 2 NO NO monitor 3 1 2 1 Principle of the method Oxides of nitrogen NOx and nitric oxide NO are measured either by dual channel or single channel analyzers using the gas phase chemiluminescence method The gas phase reaction of nitric oxide NO and ozone O3 produces a characteristic luminescence with an intensity proportional to the concentration of nitric oxide as follows NO 03 gt NO2 O2 hv 3 2 This reaction only takes place between NO and O3 and not NO and O3 Inside a dual channel analyzer the air sample is directed into two channels one to measure NO and the other to measure both NO and NO In the NO channel the concentration of NO can be determined simply and directly by the intensity of the characteristic light emission In the second channel NO is first converted into NO by a molybdenum converter and then the total NO is determined The difference between the second channel reading and the NO reading in the first channel gives the concentration of NO32 CUTOFF FILTER NO CELL ON AR INT GENERATOR Ja oy E PHOTOMULTIPLIER TUBE MECHANICAL ELECTRONICS CHOPPER PHOTOMULTIPLIER CELL GAS OUT TOPE NO2 NO7 CONVERTER CUTOFF FILTER Figure 3 5 Schematic of Operation Principle Model 8840 Monitor Labs Inc As shown in Fig 3 5 the NOx analyzer has two r
102. ected to the sampling inlet The operator should confirm that the flow rate is maintained in the setting value 1 5 3 0 L min In addition when the actual flow rate varies exceeding 7 of the setting value it is necessary to investigate the capability of the flow stabilizer and the suction pump air leak etc and then to perform adjustment or exchange of parts Regarding the sample air leakage it should be confirmed that the displayed flow rate is less than 0 15 L min when the sampling inlet is sealed As for the isokinetic suction pump its performance should be confirmed by the checking whether the actual flow rate varies within the allowable range from the setting value 5 Blank test It follows to the description in the section of the B ray absorption method automatic monitor Section 3 1 4 1 6 Others Since the filter oscillation method is a measurement method using the oscillating element when the equipment is installed the location with flat and minimal environmental vibration should be chosen 3 1 4 3 Dehumidifier system For PM automatic monitor it is required to have a function which controls change in the measured value due to the variation of relative humidity in order to obtain the measured value equivalent to the filter collection weighing method The increase in the mass concentration measured value due to moisture absorption of the ingredient in particles is pointed out on the PM measurement The mass of PM is easi
103. een calibrated by a traceable primary flow standard with a flow calibration curve in the form of linear regression show below y mx b 3 1 Where y true flow in standard condition x flow reading of the calibrator m slope b intercept Ensure the connection of the pneumatic path is from the output of the multigas dynamic calibrator in the order of the manifold controller the manifold block the manifold controller then the SO analyzer s sample inlet If trouble shooting required the connection can make directly from calibrator to analyzer Ensure the gas cylinder securely to the dynamic calibrator If connections are re established activate the control valve of the calibrator to allow SO gas to pass through the calibrator Purge the regulator and delivery system for calibration gas properly prior to calibration to avoid any undesirable back diffusion of air into the gas bottle Adjust the diluent air flow to be not less than 100 and more than the normal working flow rate of the analyzer Activate calibration at ZERO mode by the data logger Or activate the calibrator in local mode the Zero button Introduce zero air to the analyzer for 15 20 minutes Record the stable response as unadjusted zero response Adjust the analyzer zero pot to read this as zero plus a little offset 1 3 ppb Activate the data logger or analyzer at SPAN mode Then introduce span gas into the calibrator Select the correct concentration to the
104. emperature Add 4ml Diethyl ether to remove PTIO Do it two times Add 2 ml Color producing reagent and shake gently Store it for 30 minutes in refrigerator Send them to colorimetric analysis at a wavelength of 545nm Wastewater should be treated 4 3 5 Calculation of concentration from collected amount As mentioned in Section 4 3 1 the sampling rate can be calculated using the Fick s 110 Manual for Air Concentration Monitoring first law of diffusion from the cross sectional area perpendicular to the transport direction and the distance that the gas has to diffuse However the sampling rate is affected by the ambient temperature The empirical equations correct such dependency to the standard condition Yokohama City Research Institute of Environmental Science 2010 Here shows the equations to calculate ambient air concentrations The Fick s first law of molecular diffusion is shown below J D Ac Ax 4 9 Where Ac Ca Co Ax L Lo J transport amount D diffusion coefficient And the Practical use of the Fick s Law is shown below J D CIL 4 10 Where J transport amount ng cm sec D molecular diffusion coefficient cm sec C concentration ng cm L diffusion length cm Then JA DA C L ng sec Wit 4 11 Where A collection area cm W weight of collected substances ng t sampling time min In the active sampling collection rate ng min can be expressed by
105. epared Rather simple criteria such as upper and lower limit could be used for routine data check activities Check of QA QC activities maintenance of the instruments should also be included in this procedure 7 5 2 Confirmation of measured data Confirmation of the measured data is the procedure for finding missing and abnormal data and validating the measured data by comparing them with various kinds of information such as operation and maintenance reports Confirmation of measured data should be carried out when the monthly reports are prepared If the data at the monitoring station can be access to the other offices the preliminary data should be compared to the previous data Although it is desirable to check all the measured data every day it is extremely troublesome and therefore in some cases the monitoring data for every 5 or 10 days will be checked 7 5 3 Data screening Data screening is the process to identify abnormal data based on the certain criteria Such criteria may be established taking into account the hourly daily monthly averages for the previous several years and their statistic characteristics The methods generally used for screening include Methods using the previous data of the concerned instrument such as upper and lower limits of measured data upper or lower limit of difference with the previous data Methods using change of measured data taking account of differences of daily or other per
106. eping safety and preventing thunderbolt influence to the instruments and the data collection device etc 3 Room light The lighting of brightness enough for the work of check and adjustment of the monitors etc is required and it is desirable to secure more than 120 W per 10 m by using fluorescent light In addition it is desirable to prepare a flashlight for checking inside the monitor or preventing hand darkness Manual for Air Concentration Monitoring 4 Ventilation fan It is necessary to install a ventilation fan for gas leak measures Especially when the station is established in the inside of the building installation of a gas detector an automatic alarm sensor and a power supply breaker is desirable because of safety measures Moreover placing a ventilator is also desirable In this case it is necessary to attach a filter to the ventilator to avoid the inflow of ambient particles and dusts 5 Air conditioner The temperature inside the station may sometimes exceed the allowable range of automatic monitors working in the station due to heat sources such as a sample air exhaust pump and a heater for temperature adjustment especially during high temperatures in summer Therefore installation of an air conditioner is required to operate the instruments correctly Although the cooling capacity to be installed into the station depends on the size of the internal space structures etc it may be necessa
107. er g cm Since it can be considered that the mass absorption coefficient um is constant without basing on the composition of particles the mass of PM xm can be calculated from the ratio of Z to Jo xm 1 um 1 1 3 13 2 Instrumental setup The setup of a typical PM monitor by the B ray absorption method is shown in Fig 3 17 filter i particle size classifier flow controller sample gas inlet flow meter detector Figure 3 17 PM monitor by B ray absorption method 3 Filter A collection filter that the collection efficiency is 99 7 or more for the particles with the diameter of 0 3m is used Moreover it is desirable to use the filter of manufacturer recommendation The tape type glass fiber filter with the length which can be continuously monitored for 1 to 3 months is generally used In addition since the moisture influence to the filter paper causes the measurement error it is needed to pay attention to the dew condensation in high humidity period 4 Notes for measurements 1 Sampling air system i Sampling inlet A Manual for Air Concentration Monitoring The individual sampling inlet shall be used for PM sample collection instead of the manifold method fundamentally The measures to prevent the penetration of rainwater insect etc into the sampling inlet are recommended ii Materials of sampling tube The sampling tube which has smooth and clean inner and doe
108. eramongkol Pollution Control Department Thailand Secretariat Dr Ketichi Sato Ms Naoko Take Dr Mingqun Huo Dr Tsuyoshi Ohizumi Network Center for EANET Atmospheric Research Department Asia Center for Air Pollution Research iv Manual for Air Concentration Monitoring Preface Air concentration monitoring is one of the basic monitoring items in EANET and the air concentration data are intended to use for dry deposition flux estimation and clarify the state of air pollution in region EANET previously published several documents regarding for air concentration monitoring One is QA QC Program for the Air Concentration Monitoring in East Asia published in 2001 and the other one is Technical Document for Filter Pack Method in East Asia in 2003 Also Technical Manual for Dry Deposition Flux Estimation in East Asia 2010 described brief outline of air concentration monitoring However there is no comprehensive manual for air concentration monitoring in EANET countries which enable to standardize air concentration monitoring and provide comparable data at EANET monitoring sites The Expert Group on Preparation of Technical Manual for Air Concentration Monitoring composed of relevant experts is established in November 2009 The Expert Group reviewed current monitoring methodologies of air concentration monitoring both in EANET participating countries and international networks Then the Expert Group prepared the Technical Manua
109. erformances Vv p_e L A Check Sn a Check absolute deterioration wearing out i Performance of instrument Time Figure 5 2 Example for changes in instrument performances by aged deterioration Ministry of the Environment Japan 2010 5 3 2 Contents of maintenance Table 5 1 shows the sections objectives frequency and contents of maintenance Detailed explanations are shown below 1 Visual check Normal operation of an automatic monitor is checked when the local operator visit the site If instrumental data e g air concentration flow rate instrumental temperature can be seen through the telemeter system the responsible person should check such data When abnormalities occur the operator or the other responsible person must take efforts to resolve the problems in order to reduce missing data At the station instrumental status such as temperature pressure flow rate error codes should be observed by the local operator Missing data should not only be recorded as no data but also the reasons of missing data should be recorded in order to use for maintenance and data verification 2 Daily check Daily check is to confirm operating statuses of the instruments and it should be conducted once or twice a week At the daily check the local operator or the maintenance contractor should check the abnormalities of instruments and replace consumable parts according to the necessity
110. es U S Environmental Protection Agency 2013 4 Calibration method of an ozone monitor located in a monitoring station 230 Manual for Air Concentration Monitoring The ozone monitor should be thoroughly checked by the site technician on a regular basis every six months but additional internal calibrations are required after any monitor malfunction repair before and after any change or manipulation in the instrument such as UV lamp replacement mirrors and absorption cell cleaning etc as specified by the ozone standard operating procedure SOP For this purpose the ozone generator should be available at the site that has been compared with the transfer standard traceable to the NIST SRP Before and after a change or the Teflon tubes and filters the zero check with a carbon active charcoal manganese dioxide or equivalent filter should be performed The scrubber efficiency may vary with the level of ozone concentration and the site technician should be aware of this possibility The accuracy of a ozone monitor located in a station shall be maintained within 5 at level of 200 ppb between successive primary calibrations Other notices A calibration log will be maintained for each site containing dates and times of calibration name of person making entry calibrations values and sensor responses before and after adjustments A zero span precision and shelter temperature record will be kept and control charts will be maintained
111. esponsible person will ask the repair service staffs dispatched by the manufacturers 5 3 3 Lifetime of instruments Because automatic monitors and the other instruments work for 24 hours per day for a long time it is unavoidable to consuming the component parts by long use The standard lifetime of the instruments would be 10 years in general even if each one is maintained properly by daily or periodic check and maintenance inside of the station If instrument is placed on the outside of the station general lifetime would be 7 years It is necessary to replace of each monitor based on these periods Some instruments must be replaced in the fixed period by laws For example in the case of Japan the official certified meteorological instruments should be replaced in every five years because of expiration of the certificate In this case the expiry period would be one of the indication of replacement If it is difficult to replace the instruments because of budgetary limitations the responsible person should ask the manufacturers about longer maintenance so that operating costs should be kept as low as possible In addition disposal of the instruments must follow the laws in each country 5 3 4 Overhaul Some instruments must be used for longer than their standard lifetimes in some cases Generally the precision of the instruments decrease with the operation time even if sufficient maintenance is carried out Therefore the frequency of perio
112. fold and then connect to the output of the Model 146 calibrator Thermo Fisher Scientific Inc Plug the ozone outlet of the manifold Operate the calibrator to feed an ozone testing gas at precision level about 90 ppb into the ozone analyzer Record the certified concentration of the precision check and the stable analyzer response into the precision check data sheet for ozone Calculate the adjusted response and then the precision for reporting Restore the connections and settings for normal operation Complete the precision check data sheet and record the percentage difference Check whether precision check result exceeds 20 Record the result on the precision check control chart By Other Ozone Calibrators 1 2 3 4 5 6 7 8 If a certified ozone calibrator is available in the station a precision check can easily be done by the ozone calibrator Connect a zero air supply to the ozone calibrator Warm up the calibrator for about 30 minutes Disconnect the analyzer from the station manifold Cap the manifold outlet for ozone and then connect the ozone calibrator to the analyzer A vent should be provided at the analyzer input and sufficient vent air should be maintained during the precision check If an independent sample inlet is used for ozone the test gas should be fed in via the sample air intake point Adjust the ozone calibrator to generate an ozone gas concentration of 90 10 ppb When the ana
113. g and closing of a valve should be performed slowly and the valve should not be fully opened by any means 6 Indicated value of air free from particles blank test The filter paper which has little air flow resistance and can fully remove a particulate matter is set in the filter paper holder Then the holder is connected to the sampling inlet 44 Manual for Air Concentration Monitoring and the sample air free from particulate matter is measured for 24 hours It is called the indicated value examination blank test to the air free from particulate matter It shall be checked that the arithmetic mean of the hourly value does not exceed 10 pg m or 1 of the maximum scale The f ray absorption method theoretically accompanies the probable error of nuclide collapse therefore the production of the counting error about 10ug m is not avoided In this reason an 6 14 12 0 8 6 4 2 0 2 4 6 8 0 2 4 16 examination value and a measurement walie tim sometime Figure 3 18 Example for indicated value of intoa minus vali air free from particles blank test Although some models may process the measured value below zero and display it as zero the function should be cancelled to prevent the positive error bias An example of a histogram of this examination values is shown in Fig 3 18 7 Replacement of pump and its related parts Although the frequency of the replacement for the pump and some parts around the
114. g the MFC settings for span check it is desirable to select the gas MFC to be 100 By the equation 3 9 and assuming that NO ou 900 ppb the zero flow can be estimated and a suitable setting can be selected 9 From the selected settings the SGC standard gas concentration for NO and NOx in span check can be calculated by flow equations and the equations 3 9 and 3 10 10 The settings for a precision check can be determined by setting the zero flow MFC to be 100 11 Likewise settings for the mid point concentration can be determined NO concentration is about 500 ppb 12 Usually the standard gas concentration of NO gas is 50 ppm the ranges of zero and gas MFCs are respectively 10 LPM and 100 cc min 3 1 3 O3 monitor 3 1 3 1 Principle of the method The 254 nm ultraviolet light absorption method is used for ozone monitoring The method is based on the direct gas phase absorption of ultraviolet light over a narrow band The sample air first passes through a selective removal system for ozone then enters the absorption cell and absorbs a certain amount of the ultraviolet light and this is stored as the reference Then in the next cycle sample air enters the cell bypassing the ozone selective scrubber and the ultraviolet absorption is again stored Fig 3 9 The difference between the two values is proportional to the ozone concentration according to Beer Lambert equation 254 mm SOURCE ABSORPTION CELL DETECTOR DIGI
115. gas phase titration GPT by which the converter efficiency of the MOLYCON can be estimated also Gas phase titration When the standard NO gas reacts with ozone NO is produced according to the following equation NO O gt NO O2 3 8 The quantitative nature of this reaction is such that when the NO concentration is known the concentration of NO can be determined Ozone is added to excess NO in a dynamic calibration system e g Model 146 Thermo Fisher Scientific Inc and the NO channel of the analyzer is used as an indicator of changes in NO concentration Upon the addition of O3 the decrease in NO concentration observed on the calibrated NO channel is equivalent to the concentration of NO produced The amount of NO generated may be varied by adding variable amounts of O from a stable ozone 29 Manual for Air Concentration Monitoring generator Set up of calibration system 1 The regulator and delivery system for calibration gas must be purged prior to the start of calibration to avoid any undesirable conversion of the standard NO to NO and back diffusion of O3 into the gas bottle 2 Connect the calibration set up 3 Ensure that the mass flow controllers MFC of the dynamic calibrator have been calibrated with a flow calibration curve in form of y mx b by linear regression where y true flow in std condition x reading b intercept m slope The relationship between the actual flow rate and t
116. ge in concentrations of NO and NO can occur due to the reaction of NO with O in the sampling line In order to avoid a significant change in the concentrations of NO and NO the residence time in the sampling system from the sampling inlet to the monitor shall be less than 2 seconds The increase in NO can be calculated by the formula given in Annex A of ISO 13964 International Organization for Standardization 1998 Calculation of residence times for a maximum allowable NO increase in the sampling line The increase of the sampled nitrogen dioxide NO2 is due to the effect of the reaction of ambient ozone O3 with nitric oxide NO in the sampling line By means of the following formulas the influence of the residence time on the increase of NO2 in the sampling line can be estimated b x O O OE 2 1 sho O NO ceo where 132 Manual for Air Concentration Monitoring O3 o is the ozone concentration at the sampling inlet O3 is the ozone concentration after t seconds of residence time in the sampling line NO is the nitric oxide concentration after t seconds of residence time in the sampling line b is the concentration difference between O3 and NO b O3 NO with b 0 k is the rate constant for the reaction of O with NO k 4 43x10 nmol mol s at 25 C and t is the residence time in seconds The increase of NO from the reaction of ozone and nitric oxide is calculated from th
117. he display is Actual flow rate m Display b 4 By the flow equation of the MFCs choose settings to produce span NO gas of concentration about 900 ppb precision NO gas of concentration about 200 ppb and in addition NO gas of mid point concentration about 500 ppb The guidelines for settings are as follows Selection of settings 5 The diluent air flow should be at least 100 more the normal working flowrate of the analyzer e g 1 0 LPM for a Model 8840 Monitor Labs Inc and 1 7 LPM for a Model 42 Thermo Fisher Scientific Inc 6 The flow settings depend on the concentration of gas standard and the ranges of the MFCs Besides MFCs should work on gt 20 of URL to minimize error 7 The NO concentration input to the analyzer can be calculated by the equation 39 Fvo NO x NO _ x DF 3 9 out Jea F F Joa NO Zz NO Where DF dilution factor Fyo Fyo F NO a certified concentration of the undiluted NO standard Fyo actual flow rate of NO standard gas flow rate corrected by MFC flow equation Fz actual flow rate of zero air corrected by MFC flow equation Similarly the NOx concentration input to the analyzer can be calculated by the equation 3 10 30 Manual for Air Concentration Monitoring NOx NOX XDF NO y HNO ln XDF 3 10 out imp Where NO2 np certified concentration of NO impurity in the standard NO cylinder 8 In calculatin
118. hould be carried out by the parallel measurement dynamic calibration with the standard method using the particle for calibration in principle All PM gt 5 monitors should be comparable with the PM Federal Reference Method FRM U S Environmental Protection Agency 1997 and the on site parallel measurements between PM gt 5 monitors and the FRM sampler should be conducted However the calibration using the equivalent input material is acceptable although it 253 Manual for Air Concentration Monitoring doesn t follow the dynamic calibration It is difficult for the installation administrators and local operators to calibrate the monitor by the dynamic calibration in the periodical check and maintenance Therefore the static calibration using the equivalent input material is enough as the routine calibration for keeping their performance well 1 Scale calibration for B ray absorption method automatic monitor In the case of the ray absorption method as equivalent input material corresponding to the collected particle mass an equivalent film tool which is consisted of the Maira or polyimide thin film in a cartridge is used for the static sensitivity check However since the static sensitivity check is no more than the method to confirm the detector sensitivity and the operating status of the arithmetic control part the confirmation by the parallel measurement with the standard method FRM under the sample air is needed to check
119. ide to ensure that ozone undergoes no decomposition upon exposure to the internal surface of the cells 4 Two 0 018 capillary tubes restrict the sample flow passing through each absorption cell at 1 LPM The two flowmeters provide the corresponding flow indication 5 The internal pump provides the driving force to draw air into the photometers 6 The pneumatic path of the internal ozonator is comprised of three parts namely the flow control pressure regulator followed by a capillary tube ozonator and distribution manifold 7 The zero air flow entering the ozonator is held constant by the flow control regulator followed by the capillary tube It is normally set between 8 10 psig with at least 3 LPM of zero air passing through the ozonator The external zero air supply should be able to supply 3 5 LPM of zero air at 20 psig 8 The ozonator operates on the photolytic principle The ozone level produced is a function of light intensity at 185 nm and zero air flow Since the zero air flow is held constant so the ozone concentration could be varied by changing the current into the UV lamp 9 The distribution manifold is all Teflon with three outputs one to supply the photometers one to supply the other ozone analyzer being calibrated and one for the atmospheric dump 10 When the Model 49 is in calibration mode the zero span solenoid is energized which directs the ozone from the internal ozonator to the photometers 11 The intern
120. iewed the previous Technical Document for Filter Pack Method in East Asia and the QA QC Tg Manual for Air Concentration Monitoring Program for the Air Concentration Monitoring in East Asia Then the Expert Group identified monitoring methods suitable for EANET air concentration monitoring The objective to prepare this manual is to provide guideline of air concentration monitoring based on identified monitoring methods and to standardize air concentration monitoring methodology 1 3 Priority chemical species in EANET and mandatory metrological parameters The Strategy Paper for Future Direction of Dry Deposition Monitoring of EANET Second Edition EANET 2005 had highly recommended the following priority chemical species for EANET dry deposition monitoring in view of their serious impacts on the ecosystem and human health This technical manual intended to describe monitoring methodologies for chemical species shown here First priority SO O3 NO NO urban HNO3 HCl NH3 Particulate component S047 NO3 Cl NH4 Nat Mg K and Ca PMyo Second priority NO rural and remote PM 5 Also this manual includes monitoring methodology of the mandatory metrological parameters shown below These parameters are used for evaluation of wet and dry deposition and also providing local meteorological information Metrological parameters Wind Speed Wind direction Temperature Relative Humidity Solar radiation Pre
121. igure 3 3 Optics System Schematic A hermetically sealed UV lamp is pulsed at a rate of 10 times per second The UV light is focused with a condensing lens onto the mirror assembly The mirror module acts as a reflective bandpass filter which selectively reflects only those wavelengths used in excitation of SO molecules Fig 3 3 It also intensifies and stabilizes the radiation reaching the reaction chamber The UV light passes through a relay lens into the reaction chamber A circular baffle helps to keep stray light from entering the actual detection volume Another condenser lens collects and focuses light from the reaction Manual for Air Concentration Monitoring chamber The light collected is further bandpass filtered before reaching the photomultiplier tube The photodetector facing the UV light source continuously monitors the incident light and helps to automatically compensate for the fluctuation in the UV lamp output Electronics PHOTO DETECTOR VOLTAGE OUTPUTS PPM SWITCH DEJEIHIE Figure 3 4 Electronics Block Diagram The photomultiplier tube PMT transforms the light intensity into current The pre amplifier PRE AMP converts the current into voltage Fig 3 4 The signal voltage is amplified by variable gain amplifier according to the range setting An electronic gate functions to synchronize the signal with the flash lamp pulse The timing circuitry generates the signals used to initiate both the
122. ilter pack The filter pack method has an advantage that it enables one to collect particles and gases simultaneously However one has to be aware of the fact that it is subject to artifacts in the measurement of HNO NH and HCI at high ambient temperatures Therefore the filter pack method is used for total sum of gaseous and particulate NH total NO and total Cl monitoring It should be emphasized that filter pack method does not ensure completely precise measurement due to possibility of artifact problems For example volatilization of particulate NH4NO3 and NH Cl after collected on a filter caused by increase of temperature during sampling period could occur The volatilized compounds are collected as gases such as NH3 HNO and HCI on following filters In addition high humidity might cause a reduction of gas concentration measured by filter pack method _85 Manual for Air Concentration Monitoring due to trapping of gases by condensed water in the filter pack Previous studies however provided some evidences that the artifacts are not so significant EANET 2003 The uncertainty of this method is also different among urban or remote site A bias may be introduced if the aerosol filter becomes wet during sampling since it is possible to have absorption of sulfur dioxide on cellulose based filters This gives an overestimation of the sulfate concentrations in aerosols and a corresponding underestimation of the sulfur dioxid
123. imeter Therefore the light beam slightly diverges along its path through the atmosphere resulting in a loss of light depending on the distance from the retro reflectors Furthermore caused by the two plane mirrors along the optical axis of the telescope only a ring of light can be sent out to the atmosphere leading to a loss of light intensity of up to 65 Retro reflector The retro reflectors were comer cubes quartz triple prisms of 600 mm diameter which are mounted in a thin metal or plastic housing Within a precision of 2 arc sec the incoming light is reflected back to the telescope Usually a number of retro reflectors are arranged very close to each other forming a retro reflector array The retro reflector array used in this work consisted of 19 corner cubes Quartz fiber and mode mixer The light from the telescope is transmitted to the spectrograph by a quartz fiber to ensure a stable illumination of the grating and the PDA independent from the telescope orientation The standard quartz fiber installed in the HMT DOAS is a multi mode step index fiber with a numerical aperture of 0 12 A general problem of the use of quartz fibers for light transmission in LP DOAS instruments are interference fringes produced by the total reflections within the fiber as the light leaves the fiber interference patterns in the shape of concentric circles and rings featuring different light intensities can be observed Stutz and Platt 1997 Due
124. in pure water The fourth filter F3 is made of cellulose filter diameter 47mm impregnated with a solution of 5 phosphoric acid 2 glycerin in pure water The solution to be used for impregnation should be prepared on the same day when the impregnation of a new series of filters is conducted Filters and extraction solutions should be handled in the laboratory only under the clean conditions Moreover they should not be exposed to air longer than necessary due to a possible uptake of gases by filters or solutions Disposable plastic gloves and tweezers should always be used when handling filters Only a clean filter holder should be used to prevent excess contamination Filters especially impregnated one should be always sealed up to avoid the contamination by unexpected ambient pollutants before or after the sampling time The following procedure may be used for the filter pre treatment The filters should be placed on hygroscopic papers such as chromatography papers after the impregnation solution is dripped on the filter Then the moisture should be removed by pressing the hygroscopic papers When the filters are dried they must be placed in plastic bags and the zippers closed The bags should be labeled with the type of filters and the preparation date Recommended preparation procedure of alkali impregnated filter F2 is described as the following steps 1 Prepare the mix solution 6 KCO 2 glycerin Prepare three 500 ml be
125. ing and the filter pack method Data completeness describes the fraction of valid data coverage length in a certain monitoring period Data completeness also should be described in the report form The definition of data completeness is expressed as follows Data completeness for automatic monitor p Number of valid hourly data Number of total measured hourly data 6 1 Data completeness for filter pack and other manual methods Number of valid measurement days Number of total measurement days 6 2 In order to evaluate monthly and annual air concentrations and monthly and annual dry deposition fluxes the data completeness should be no less than 70 Otherwise those data will be flagged in the report 6 3 3 Analytical precision The precision of laboratory chemical analyzes of blank samples for the filter pack method should be tested and be reported by the method described in the Section 4 1 7 6 3 4 Data flags and invalid data To indicate quality information to data users data flags and or data comments are useful they will indicate whether a data is valid or invalid The function of the flags and comments is to ensure that the user has full knowledge of the data validity and of conditions which produce that level of validity Thereby the user can select the data most appropriate to his her application Code number of data flags 999 Missing measurement data 781 Below detection limit 701 Less accurate than
126. ing in spite of the flow rate decreases and the others will stop the sample collection However when the repetition measurement is performed sampling time for a sample will decrease and an error will increase Especially for the monitoring station which is easy to be influenced by the gas exhaust from the vehicles it is recommended to select the pump which can respond to increase of the air flow resistance by the exhaust particles prone to clogging 5 Confirming actual flow rate and adjustment of flow rate stabilizer The actual flow rate of the sampling air is determined by the standard flow meter connected to the sampling inlet and its value will be compared with a setting flow rate 43 Manual for Air Concentration Monitoring A flow stabilizer or the sensor position of a float type variable area flow meter is adjusted so that an actual flow may turn into a setting flow In addition when the actual flow rate varies exceeding 7 of the setting value it is necessary to check the air leakage from the stabilizer the suction pump and the filter paper holder etc and perform adjustment or exchange some parts The confirmation of the control facility of the flow stabilizer is performed by the following method i The standard flow meter equipped a valve at the exit side is connected to the sampling inlet ii A differential pressure gauge is built into the pipe which connects a pump with a filter collection part However this ste
127. iodic variations Methods using rate of change in measured data with data of the same time on other days or Methods using other parameters of the same monitoring stations and or same parameters of the neighboring stations Such data screening can be conducted manually if the volume of the data is not significant However a part of data screening activities is in many cases computerized 140 Manual for Air Concentration Monitoring Abnormal values may be caused by measurement collection transmission of data and data processing Once abnormal values are identified the cause should be carefully analyzed 7 5 4 Treatment of abnormal data To ensure certain level of reliability abnormal data should be identified and identified abnormal data should be adequately treated These activities are called as treatment of abnormal data Abnormal data can be identified through routine data check confirmation of data and or data screening Such data can still be used if it is confirmed that the measurement is appropriately conducted If it is confirmed that appropriate measurement is not conducted due to some reasons such as inadequate maintenance activities then the data should not be used There are many factors to possibly cause abnormal data as follows Measurement system problems of intake tube the instrument the recorder and CPU Data collection system problems of the telemeter outputs the reset signals and th
128. ir conditioning 2 2 4 Height of sample inlet 2 2 5 Air sampling method 2 2 6 Note on monitor installation 2 2 7 Safety requirement 2 3 Monitoring frequency 3 Automatic monitoring 3 1 Point measurement 3 1 1 SO monitor 3 1 2 NO NO monitor 3 1 3 O3 monitor 3 1 4 PM and PM monitors 3 2 DOAS measurement 3 2 1 Principle of DOAS 3 2 2 NO monitor 3 2 3 O3 monitor 3 2 4 Evaluation procedure
129. ird small circle mirror was attached on the side of the telescope The first reflects the light coming from the lamp to parabolic main mirror A parallel outgoing light beam is obtained if the light source is placed in the focal point of the main mirror A retro reflector array at a distance of several hundreds to kilometers was used to reflect the parallel light beam exactly back into the telescope where it is focused through the main mirror The light reflected by the second elliptic plane mirror was focused by the third mirror onto an 8 m long optical quartz fiber with a 200 um core diameter and a 0 16 numerical aperture The quartz fiber passes a mode mixer and transmits the light into the spectrograph There were two shutters for the lamp and outgoing light in the telescope The first mounted between the lamp and telescope could block the light from the lamp allowing obtaining the background signal The second shutter was located in front of the first plane mirror If the second shutter was closed the light from the lamp could not reach the main mirror and directly reflected by the second plane mirror through the hole of the first plane mirror allowing recording the signals of light without transmission of the atmosphere 65 Manual for Air Concentration Monitoring The optical image of the light beam emitted through the telescope is not perfect as the light source is no real point source but shows an expansion of about one square mill
130. is mounted in a temperature controlled insulated aluminum block that provides the necessary thermal stability The UV lamp will be ignited only if the temperature is above 50 C The detectors and associated pre amplifiers are mounted together in a small well shielded can to ensure the highest levels of detector stability and the lowest levels of noise The detectors are small solar blind vacuum photo diodes and their frequency 35 Manual for Air Concentration Monitoring output is directly proportional to the light intensity The pressure and temperature transducers sense the pressure and temperature inside the absorption cells for temperature pressure correction POWER SUPPLY MODULE REFERENCE SOLENOID AMPLE SOLENOID OZONATOR CONTROL PANEL TEMPERATURE TRANSDUCER NOTE EITHER THE PO NOTE 2 ABSENT IN MO NOTE 3 IT 18 EITHER THE SETER FOR SETTING OZONE LEVEL E IN MODEL 49 OR OZONE LEVEL IN MODEL 49F53 IS PRESENT FF CONTROL FOR ZERONSPAN SOLENOID IN MODEL 49 OR OZONE LEVEL CONTROL IN MODEL 49PS Figure 3 14 Electronics block diagram of ozone monitor The ozonator consists of a UV lamp and a lamp heater module with a thermistor The light intensity is varied by changing the current into the lamp which generates various ozone levels As in the optical bench the ozonator is maintained at constant temperature to ensure the thermal stability The power supply module typically houses the ozona
131. ise test a stable halogen lamp with a stable power supply should be used to exclude any fluctuations arising from this source Other optical noise sources are the fiber which will change its transmittance with different bending Also other components like mirrors and lenses can be responsible for optical noise if they change the spectrum with time The spectrograph with the grating can produce optical noise especially if the fiber will not homogeneously illuminate the grating and the detector of the spectrometer In this case changes in the light distribution can lead to spectral structures To prevent such inhomogeneous distribution a mode mixer is applied As the noise test is performed with a stable light source and optical set up it will not determine the optical noise of the measurement The optical noise can only be determined by comparing the residuum of a measurement to the noise determined in a noise test 4 Instrument Noise 9 Instrument noise summarizes all noise sources arising associated with the instrument detection and data unit The main part is electronic noise In several instruments it is influenced by electromagnetic fields Thus detector spectrometer and electronic have to be set on the same ground level Another noise source is the non linear sensitivity of the detector with increasing saturation 2 Determination of the detection limit The detection limit defines the value above which the concentration of a specie
132. ison of manual monitoring and an automatic monitor 2 Evaluation of ion balance Evaluation of reliability 1 Evaluation of sensitivity fluctuations 2 Evaluation of repeated measurements analysis 3 Evaluation of field blanks 4 Comparison between measured data and lowest detection and determination limits Evaluation of results 1 Representativeness of sampling sites 2 Evaluation of sample validity 3 Evaluation of completeness for the sampling period 4 Determination of total precision 5 Management of sampling instruments laboratory measurement analysis instruments and reagent glassware 5 1 Management of sampling instruments 1 Appointment of management stuff and their supervisors 116 5 2 5 3 5 4 Manual for Air Concentration Monitoring 2 Documentation of names of manufacturers types manufacture dates and operation methods 3 Daily and regular maintenance and inspection methods including troubleshooting parts supply and recording Laboratory management 1 Appointment of management staff and their supervisors 2 Daily and regular maintenance and inspection methods including items and recording format Management of measurement analysis instruments 1 Appointment of responsible staff for each instrument and overall measurement 2 Documentation of names of manufacturers types manufacture dates and operation methods 3 Daily and regular maintenance and inspection methods including t
133. l analysis frequency range of laboratory room temperature 131 Manual for Air Concentration Monitoring 6 4 2 Analytical condition for filter pack samples The chemical analysis of the filter pack samples and control chart should be reported as the laboratory QA QC data for each monitoring station The following items are included in the form Method applied instrument name and type detection limit calibration curve 5 points ion concentrations in the deionized water when a dilution process is included data obtained from analysis of standard solution commercial SRM of known ion concentrations data from duplicate or triplicate analysis of samples data of blank filters 6 4 3 Measurement results and flags Air concentrations obtained by automatic monitors and analytical results obtained by the filter pack methods must be accurately input in the proper place in the formatted data report form The NC will provide the formatted data reporting form as a Microsoft Excel file All data should be input in the distributed data form Items to be input are listed as follows 1 Gas concentrations SO NO NO2 NOx O3 with the unit of ppb 2 Particulate matter mass concentrations PM1o0 PM2 5 with the unit of ug m 3 Analytical results of manual monitoring method with the unit of mg L In the case of filter pack FO S04 NO Cl NH4 Na K Mg and Ca F1 S04 NO CI and NH F2 SO and Cl F3 NH Du
134. l for Air Concentration Monitoring in EANET Through three meetings of the Expert Group held in August 2011 August 2012 and September 2013 the finalized draft was submitted to the 13th Session of Scientific Advisory Committee of EANET in September 2013 and the draft was endorsed Then the draft was adopted by the 15th Session of Intergovernmental Meeting of EANET in December 2013 We hope this Technical Manual will be useful documents for local operators national QA QC managers to operate the standardized air concentration monitoring in EANET Also this manual can be used as the reference describing the monitoring specifications in EANET sites December 2013 Dr Duong Hong Son Chair of the Expert Group on Preparation of Technical Manual for Air Concentration Monitoring Manual for Air Concentration Monitoring 1 Introduction 1 1 Background On the recommendation of SAC the Tenth Session of the Intergovernmental Meeting G10 held in November 2008 agreed to change the name of the Task Force on Dry Deposition Monitoring to Task Force on Monitoring for Dry Deposition and agreed to the following new terms of reference for the Task Force To further develop and elaborate the strategy for dry deposition evaluation in the region To discuss on future direction of dry deposition evaluation and provide guidance on relevant activities based on the strategy To develop the Technical Manuals for Air Concentration M
135. l operation especially in the case of analysis using spectrophotometer 1 Analytical method for SO Standard solution 1000 mg L S04 Range 0 01 5 0 mg L Apparatus for SO2 Hydrogen Peroxide Platinum fiber 0 1 mm 2 cm Analytical operation Add 0 2 ml of Hydrogen Peroxide solution 1 75 solution and then shake gently Hold it for 10 minutes Then add Platinum fiber 0 1 mm 2 cm and soak it into water bath 50 C for 10 minutes Platinum fiber can be reused Wash platinum fiber by deionized water after chemical analysis 2 Analytical method for O3 Standard solution 1000 mg L NO3 Range 0 01 5 0 mg L 3 Analytical method for NH3 Standard solution 1000 mg L NH4 Range 0 01 5 0 mg L 4 Analytical method for NO2 NOx in the case of using IC Standard solution 1000 mg L NO7 Range 0 01 5 0 mg L 5 Analytical method for NO2 NO using spectrophotometer Standard solution 1000 mg L NO Range 0 01 1 0 mg L Apparatus for O3 NH3 NO2 NOx Test tube NOx Plastic tube NO2 Diethyl ether Ethyl ether Pipet Glass 109 Manual for Air Concentration Monitoring lt For Color producing reagent gt Sulfanilamide Phosphoric acid N 1 Naphthyl ethylenediaminedihydrochloride NEDA Preparation of color producing reagent for NO2 NOx Prepare color producing reagent immediately before use lt For Sulfanilamide solution gt Dissolve 8 g of reagent grade sulfanilamide in a mix
136. lar radiation from cloud It is slightly observed also before sunrise and after sunset 3 Dispersion solar radiation The dispersion radiation is defined as total solar energy dispersed by atmospheric molecules water vapor and aerosol etc irradiated into the plane per unit area The direct solar radiation is not included 1 Principle of measurement The actinometer uses the characteristics that the temperature of the object rises by the absorption of the heat of the energy when it receives solar radiation A thermopile is connected between the acceptance surface warm junction and the thermal reference point such as an outer shell cold junction and the difference of temperature between both junctions are measured and then it is converted to solar radiation 2 Installation criteria The actinometer should be installed on the rooftop or the plain field where direct solar radiation is not interrupted at any times and where no obstacles such as buildings trees antennas and plume sources exist If there is no ideal installation place one must select the place in which the effect from surroundings should be as little as possible Moreover it is necessary to consider convenience for a routine check and maintenance 3 Maintenance protocol 1 Daily check i Any dirt on the glass dome covering the acceptance surface is checked and the dome should be cleaned if necessary ii The moisture absorption condition of the desiccant is checked
137. lay driver board the digital analogue board I O buffer board and the front panel pushbuttons The microprocessor board controls the operation of the analyzer calibrator with the aid of other circuit boards in the microcomputer module It instructs and co ordinates other circuit boards to ensure normal operation The memory board houses the program written by the manufacturer It contains algorithms for operation control signals monitoring calculation compensation and output communication The data memory on this board can be thought of as a scratch pad for the microprocessor board and is used to store intermediate values during operation The counter board acts as the interface between all the signals monitored by the microprocessor board The signals monitored include the frequency signal from the detectors A and B the pressure and temperature in the absorption cells The peripheral interface PIA board acts as the interface between the microprocessor board and the front panel pushbuttons thumbwheel switches It also decodes the data from the microprocessor board into the format recognized by the display driver board An eight segment DIP switch is located on this board for system configuration For the model 49 Thermo Fisher Scientific Inc only segment 7 and 8 of the DIP switch should be turned ON all others OFF All segments should be turned OFF in the model 49PS Thermo Fisher Scientific Inc The display driver board contains circuitry t
138. llow cantilever beam with an associated spring rate and mass and vibrates precisely at its natural frequency As in any spring mass system when additional mass is added the frequency of the vibration decreases An electronic control circuit senses this vibration and through positive feedback adding sufficient energy to the system to overcome losses An automatic gain control circuit maintains the vibration at constant amplitude 2 Instrumental setup Through the PMjo or PM2 5 inlet the principle size separation at 10 or 2 5 um takes place as the sample proceeds The flow splitter separates the total flow into two parts a main flow of 1 5 3 0 L min that enters the sensor unit through the sample tube and the auxiliary bypass flow The main flow passes through the exchangeable filter in the mass transducer and then proceeds through an air tube and an in line filter before it 46 Manual for Air Concentration Monitoring enters a second mass flow controller A single pump provides the vacuum necessary to draw the sample stream through the system The setup of a typical PM monitor by TEOM method is shown in Fig 3 19 particle size classifier air inlet r suction system for uniform velocity detector and filter paper extraction unit flow controller element of oscillation output signal arithmetic E processor G gt Figure 3 19 Schematic diagram of PM monitor by TEOM method
139. lt in order to prevent the fall by earthquake etc i0 Manual for Air Concentration Monitoring 2 2 3 Air conditioning Even if the monitor is in the suitable temperature some monitors may induce the measurement errors when the ambient temperature differs from the temperature during the calibration Therefore it is desirable to install an air conditioner in the station in order to keep small difference with the temperature at the time of calibration or to calibrate a monitor at the temperature which the station can adjust Furthermore when the room temperature is set very low compared to the outside air in summer season to keep small the difference with calibration temperature moisture condensation will occur in a sampling tube and it may cause measurement errors and apparatus trouble To prevent those problems heat of the sampling tube is effective It is also desirable to set the room temperature taking into account the difference with the ambient air and to carry out the calibration in this temperature especially in summer time Generally temperature is set up at 28 C or more in summer to avoid the water condensation of a sample air and around 18 C in winter in many cases Figure 2 1 shows the relationship between condensation sample temperature humidity and room temperature 100 A 7 901 Region of 80 condensation ra Z 70 60 50 40 30 205 10 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Humidity
140. lter are summarized in Table 4 1 _87 Manual for Air Concentration Monitoring Table 4 1 Specifications of filters EANET 2003 Collected Stage Specifications of filters Reaction species First F0 Teflon PTFE filter Filtration Aerosol Second F1 Nylon Polyamide filter Adsorption HNO Partial SO2 HCl Neutralization by Partial NH3 collected acid gases Third F2 Cellulose filter Neutralization by alkali SO2 HCl impregnated by K2CO3 impregnated on the filter Fourth F3 Filter impregnated by Neutralization by acid NH3 phosphoric acid impregnated on the filter 4 1 4 Sampling 1 Sampling system A diagram showing the sampling system is given in Fig 4 2 The air intake should have a cylindrical vertical section 15 cm wide and at least 25 cm high This air intake reduces the sampling efficiency for particles which aerodynamic diameter is larger than 10 um such as soil dust particles large sea spray droplets large pollen and fog droplets The filter pack is placed directly in the air intake and it should have separate supports for the aerosol and the impregnated filters in order to avoid contamination from one filter to the next Regarding the sampling height of the FP system the height should be basically the same level as that of automatic instruments described in Section 2 2 4 because all air concentration monitoring instrument is located in the same stations Here shows th
141. ly overestimated when the substance which has deliquescence property such as ammonium sulfate inorganic salts and secondary organic aerosol is exposed in moisture A dehumidifier system is attached to the sample air inlet for reducing the influence of humidity in many cases There are three major methods for dehumidifier a heating 48 Manual for Air Concentration Monitoring method a diffusion pipe method and a dilution method Although the condition of operating the dehumidifier system depends on the model of a PM automatic monitor temperature and humidity are important parameters for controlling the system of many dehumidifiers It is also important to carry out a routine or periodical check and maintenance for the systems Some thermometers and hygrometers for PM monitors are beforehand calibrated at the shipment and cannot be adjusted at the site when the fixed range is exceeded the sensors should be newly replaced The others can be adjusted on software by using a correction coefficient obtained in comparison with the calibrated equipment at the site In the routine maintenance the followings should be performed 1 the check of indicated values on the monitor 2 the check of heating and 3 the comparison of temperature and relative humidity measured by the monitor with those parameters which are previously measured in the same monitoring station Moreover the indicated values of those parameters should be confirmed by using the
142. lyzer response is stable record the reading on the precision check report form Calculate the actual ozone concentration from the calibration line of the calibrator and then record on the form Calculate the adjusted analyzer response and then report the precision by the adjusted response and the actual ozone concentration Disconnect the ozone calibrator from the analyzer and then restore normal 145 Manual for Air Concentration Monitoring connection of analyzer Resume normal analyzer operation 9 Complete the precision check data sheet and record the percentage difference 10 Check whether precision check result exceeds 20 11 Record the result on the precision check control chart By Ozone standard with internal ozonator Model 49PS 1 Connect the zero air supply to the ZERO AIR bulkhead of Model 49PS ozone standard Thermo Fisher Scientific Inc 2 Operate the ozone standard in local mode and at the precision level Allow sufficient time for the ozone standard and analyzer to stabilize Stabilization can be judged by the variation of analyzer response 3 Record the stable response and the certified level concentration on the precision report form Calculate the adjusted response and take record 4 Disconnect the zero air supply resume the normal setting and connection of the analyzer and record the time period of the precision check 5 Complete the precision check data sheet and record the percentage difference
143. m outside instead of a zero point measurement mechanism with the ozone degradation machine to build in can be performed 2 Calibration method by ozone gas dynamic calibration 1 Gases for calibration 1 Zero air 2 Span gas 2 Calibration method with primary ozone monitor A simplified scheme of a primary ozone calibration system is shown in Fig 3 15 and consists of an ozone generator and an ozone monitor Flow Ozone m Output Manifold Controller Generator Air To Inlet of UV To Inlet of UV Calibration Analyser under Photometer Calibration Figure 3 15 Primary ozone calibration systems Norwegian Institute for Air Research 2001 The primary ozone monitor shall be used for only that purpose and shall be carefully maintained under stable laboratory conditions The different parts of the monitor are the same as shown in Fig 3 16 but without the catalytic ozone scrubber Every part shall be manufactured optimum care When using the expression primary monitor in this section it will normally mean a laboratory or e g a country s primary monitor It is desired that each country has each primary monitor Such primary monitor should preferably be traceable to the NIST US National Institute of Standard and Technology SRP One way of obtaining this is to buy from NIST a NIST SRP which periodically will be checked by NIST Another way is to have the laboratory or national primary calibrator traceable to NIST SRP in another
144. mental Monitoring and Assessment 122 61 79 Aikawa M Hiraki T 2008 Methodology of analysis associating survey results by the filter pack method with those of precipitation Acid base balance on acid related and alkali related chemical species in urban ambient air and its influence on the acidification of precipitation Journal of Atmospheric Chemistry 61 21 29 Aikawa M Hiraki T 2010 Difference in the Use of a Quartz Filter and a PTFE Filter as First Stage Filter in the Four Stage Filter Pack Method Water Air and Soil Pollution 213 331 339 Endo T Yago H Sato K Matsuda K Hayashi K Noguchi I Sawada K 2011 Regional characteristics of dry deposition of sulfur and nitrogen compounds at EANET sites in Japan from 2003 to 2008 Atmospheric Environment 45 1259 1267 Karakas D Tuncel S G 1997 Optimization and field application of a filter pack system for the simultaneous sampling of atmospheric HNO3 NH and SO Atmospheric Environment 31 1657 1666 Kim M G Hong Y M Kang M H Lee D S Lee B K 2001 Estimation of dry deposition by using a filter pack method at Chunchon Korea Water Air and Soil Pollution 130 565 570 Ohizumi T Nagai T Golobokova L Toruksa W W Meng X 2013 Joint Reseach Project for Developing Low Cost Methodology on Gas Concentration Monitoring in East Asia EANET Science Bulletin 3 135 145 Sickles J E II Hodson L L Vorburger L M 1999 Evaluati
145. mp S o iS vo 5 A SA 00 fa 0 0 s 0 0 2 i ce 3 00 0 0 00 3e 4 us eg 0 08 0 98 0 88 0 6 0 96 0 96 016 0 86 0 16 0 96 0 96 0 S6 016 OEL OEL 09 0 06 OL 0 09 0 9 0 99 019 0 69 0 99 0 9 0t9 0 89 0 19 0 19 Hu 0z E EZ gies Lg cre 8e 0z cal 6l k 8l GI 0 0 v0 0 ol el ol ol LO 90 c0 00 00 vy 0 l 0 amp 0 wo eeg mey 00 00 00 00 00 00 00 00 00 00 00 00 00 lo co 90 L0 G0 G0 v0 co 00 00 00 00 00 00 00 00 MNM MNM MNM MN MN MN MN MN MNM MNM MNM MNM MNM MNM 2e neeaae aee aen MNM aM L0 Ol 60 L Z L Z 0 lI 60 90 90 ol v0 LO 80 co si Lg se vv vv Ov Lv Le 8 ge Le ve se ve noH cLOG errr er er er er er er mr PP PPP OPP PRP rr KH KH NNNNAN m p pe ee p ee el el el ee el el el el RN pop p pR eH eH pp eH L Aeq yuo weyN 21S Z 4 L L 135 Manual for Air Concentration Monitoring 7 Quality Control and Quality Assurance 7 1 Fundamental matters Quality Control and Quality Assurance QA QC should cover all QA QC matters including the activities of NC the National Centers and the sampling chemical analysis organizations The National Centers and the monitoring chemical analysis organizations need to execute various QA QC activities including development of the national QA QC programs and the SOPs The following fundamental i
146. n particularly in the case of SO because it is easy to dissolve in water 7 3 2 Documentation of conditions around sampling sites All monitoring sites should essentially satisfy the siting criteria If there are some differences from the criteria they should be documented and evaluated for integrity and validity of the monitoring data Any significant changes around sampling sites should be promptly reported to NC through the National Center 7 3 3 Site performance audit A site performance audit should be made at least once a year by the National Center This audit also provides field training and exchange of information A site performance audit should also include items such as operation checks of instruments data management data reporting and so on The National Center should prepare the SOP for site audits The results of each audit should be documented and stored at the National Center 7 4 Field and laboratory operations Precision and accuracy are an integral part of laboratory quality control Ensuring that precision and accuracy meet the DQOs is an important step in the validation of chemical analyzes of manual samples and ensuring the quality control standards are sufficiently maintained 1 Analytical precision To estimate the analytical variability of manual monitoring duplicate analysis of a 138 Manual for Air Concentration Monitoring sample should be determined a minimum of 1 in every 20 samples La
147. n 0 002 in the time frame it takes to measure J and Jp in order for the photometer to have a sensitivity of 1 ppb Model 49 49PS meets this criterion by using two photometers The determination of the ozone concentration is composed of two sampling cycles shown in Figs 3 10 and 3 11 fe ABSORPTION CELL A ne DETECTORS V F _ PIST l ABSORPTION CELL B oa aia ie FLOW EXHAUST REFERENCE SOLENOID m CAPILLARY lt lt REFERENCE m SAMPLE Figure 3 10 The first sampling cycle of ozone monitor Ree i Manual for Air Concentration Monitoring EXHAUST C E DETECTORS V F ABSORPTION CELL B i ea Oe now yog a lt lt REFERENCE e SAMPLE CAPILLARY Figure 3 11 The second sampling cycle of ozone monitor The period of the sampling cycle is 10 seconds The first 7 seconds is for flushing and signal integration takes place in the last 3 seconds The photometers are two separate but similar absorption cells and detector systems sharing the same UV source In the first sampling cycle the ambient air sample enters the absorption cell B while the reference gas goes to the absorption cell A I B and J A are therefore determined In the second sampling cycle ambient air sample and reference gas goes to the absorption cell A and B respectively A and B are measured in this cycle The ozone concentratio
148. n measured by absorption cells A and B is calculated based on J A Jo A and J B I B respectively The fluctuation in lamp intensity is factored out by averaging these two readings The average value which is corrected to 0 C and 760 mmHg is used to represent the ambient ozone concentration The measurement continues by repeating the two sampling cycles the temperature pressure correction and the averaging process Pneumatic path The pneumatic path is explained by the model 49 ozone analyzer and the model 49PS calibrator Thermo Fisher Scientific Inc Model 49 1 In sampling mode the zero span solenoid is de engerized and so the ambient air sample is directed into the photometers Fig 3 12 The reference and sample solenoids are energized alternatively in the sampling cycles to synchronize but 180 out of phase the operation of the two photometers 2 The manganese dioxide inside the converter acts as the catalyst to convert the cae Manual for Air Concentration Monitoring ozone in the sample to oxygen and so provides the ozone free reference gas 2 A iz EXHAUST INTAKE PARTICULATE FILTER ASSEMBLY z 8 Bi FLOW CONTROLI S a O 0 6 O O BULKHEAD FITTING Figure 3 12 Pneumatic path for the model 49 Thermo Fisher Scientific Inc 3 The internal surface of the two absorption cells have been coated with polyvinylidine fluor
149. nd the filters are given the same chemical treatment and analysis as the exposed filters Sample filters are recommended to be dismounted from the holder in the laboratory and be kept separately in clean plastic filter cases with description of sample number Exposed filter packs should be opened in the laboratory and the filters put into plastic 9 Manual for Air Concentration Monitoring bags which in advance have been tagged with site code start and stop of sampling and filter type The filters are now ready for a chemical treatment and the analysis Normally there is a delay between this step and the time when actual chemical treatment and the analysis takes place During this period the samples are to be kept in a refrigerator It is important to wear a pair of disposable plastic gloves when working with the filters and the filter packs Example A i i Flow meter Air pump Example B Air pump 3 way valve Filter pack Fig 4 3 Operation of leak check for filter pack 2 Preparation of filter pack As mentioned in the Section 4 1 3 PTFE filter pore size 0 8m diameter 47mm is recommended as the first filter FO Polyamide filter pore size 0 45um diameter 47mm is recommended as the second filter F1 The third filter F2 is recommended 92 Manual for Air Concentration Monitoring to be cellulose filter diameter 47mm impregnated with a solution prepared by mixing 6 K2CO3 2 glycerin
150. ng inlet PM2 5 particle F PM2 5 particle size classifier size classifier Heater Heater control Signal Heater Heater control Signal SEE iaaiiai Aai PM2 5 Detector PM2 5 Detector a Temperature sensor signal g Humidity sensor signal Heater Heater Flow controller Flow controller controller controller F Exhaust Exhaust Pump gt Solid line Flow of sampling air Pump i Solid line Flowofsamplingar is Wa Temperature control type Humidity control type Figure 3 20 Dehumidifier system by the heating method It is necessary to confirm the operation condition of the thermometer attached near the filter for the type A near the PM detector for the type B at the sampling tube for the type C In the case of the monitor which the sensor record of each part remains in its memory it is possible to check the record in the comparison with the record of temperature and humidity monitored by meteorological observation instruments The content of the routine maintenance depends on the types As for the type A the preset value of the humidity for starting heat is confirmed to be almost same as the humidity displayed on the monitor The setting temperature of the heating part is confirmed to be almost same as the temperature displayed on the monitor for the type B As for the type C when the humidity exceeds the setting value the implementation of the predetermined heating schedule should be confirmed by the humidity displayed on the monit
151. ng monitoring duration 4 3 1 Basic principles A passive sampler is a very simple device consisting of an impregnated filter or molecular sieve which preferentially sorbs the gas to be analyzed and a diffusion barrier usually an entrapped air volume that keeps the sampling rate constant If the sampling efficiency is sufficiently high then the sampling rate can be calculated using the Fick s first law of diffusion from the cross sectional area perpendicular to the transport direction and the distance that the gas has to diffuse The sampling technique is based on the property of molecular diffusion of gases 103 Manual for Air Concentration Monitoring hence the term passive also referred to as diffusive sampling The gas molecules diffuse into the sampler where they are quantitatively collected on an impregnated filter or an absorbent material Therefore they achieve a time integrated or averaged concentration No electricity pumps or other supporting equipment are needed Inorganic gases are absorbed by chemical reaction on a filter impregnated with a solution specific to each pollutant measured The reaction product which is washed out of the filter prior to analysis is specific to the target gas When species do not react sufficiently fast with other chemicals e g organics they are instead trapped on an absorbent material Such gases are then desorbed from the adsorbent during analysis To work properly and quantit
152. nges its separation characteristics with the dirt on the surface of the inner wall the big and rough particle receptacle part as well as the inner wall of the classifier should be periodically cleaned by using alcohol neutral detergent etc The cascade impactor should be disassembled and cleaned at least once a year Wipe the dust residue on the impactor plate and nozzle Then compressed air can be used to blow it off Isopropanol or soap and water can be used for cleaning the parts but make sure that they are dried before reassemble Moreover at the opportunity of the classifier cleaning it is better to be cleaned and replaced whole parts between the sampling inlet and the detector 2 Exchange of collection filter Although the exchange frequency of collection filter paper differs depending on the model a roll like collection filter paper needs to be exchanged once for 1 to 3 months 42 Manual for Air Concentration Monitoring However since many repetition measurements in a high concentration period and high frequency calibration by using the equivalent film cause faster filter consumption in comparison with usual measurement the operator should be paid enough attention for the residue of the filter paper not to produce missing period In addition when the collection filter paper is exchanged it is required to perform the static sensitivity check which certainly uses an equivalent film When the measurement error is out of allo
153. nitoring 2 Monitoring design The purpose of this chapter is to describe the general concepts for establishing the ambient air quality monitoring network The network may be consisted of fixed station over the EANET region The station is expected to monitor the parameters of sulfur and nitrogen compounds associated with acid deposition problems PM and O associated with air quality issues meteorological parameters associated with local meteorology and estimation of dry deposition flux The station is generally required to locate in background areas that have minimal influence from manmade point or area source As well as the station will provide representative measurement of air quality entering the air shed with point or area source or climate change However the station may also be located in urban or other area where assessment of ambient air quality is needed Each monitoring station nominated in the EANET should be described in term of physical dimension of representativeness EANET 2000 It is closely associated with the area around the station where the pollutant concentrations are seasonably similar The network design intent in sitting the station is to correctly match the representativeness with the basic monitoring object of the station Station site are classified into three basic site categories remote rural and urban Multiple factors are considered when deciding the location of air monitoring station Sites are selected base
154. normal mid night zero span check position to apply span gas about 70 90 of full scale to the analyzer Wait for about 25 30 minutes and record the stable reading as unadjusted span reading on the data sheet 10 Adjust the analyzer s SPAN pot to read the span gas concentration Wait for the analyzer s reading to stabilize and then record the reading as adjusted span reading Due to interaction between zero and span pots if substantial adjustments 203 Manual for Air Concentration Monitoring of the span pot are necessary recheck the zero and span adjustments by repeating the steps 7 10 11 Select a concentration of about 50 of the span value about 40 50 of full scale by the ZERO gas thumbwheel switches of the calibrator Record the analyzer s stable readings and the actual concentration 12 Select the concentration at the normal precision check level 90 ppb 10 ppb by the ZERO gas thumbwheel switches of the calibrator Record the analyzer s stable reading and the actual concentration 13 Apply zero air to the analyzer and then record the stable zero response as zero response 14 Apply span gas to the analyzer and then record the stable span response as span response 15 Plot the analyzer s response versus the input concentration by linear regression For an acceptable linearity check the following two criteria should be met i Plot the analyzer responses during calibration with respect to the i
155. nput testing concentration by linear regression in the form of y mx b where y represents the analyzer response and x represents the pollutant concentration The correlation coefficient 7 should be greater than 0 9975 ii The deviation of the analyzer response at low level precision check level should be less than 10 If any of the above criteria are failed investigation should be initiated Repeat all the points or the point with the greatest deviation Check the flow of the calibrator if required If the linearity check still fails after repeating the points the analyzer needs trouble shooting Refer to relevant appendix and equipment instruction manual Consult the maintenance service if necessary 16 Restore the sample connection of the analyzer and the calibrator in the remote mode Reset thumbwheel settings of the calibrator to meet other automatic calibration conditions 17 Recheck that the controls of the analyzer are at the normal operation modes 18 Reset the data logger to normal operation modes if it has been altered 19 Complete the dynamic calibration data sheet 20 Complete the precision check data sheet and record the percentage difference to the previous results Check whether precision check result is within 20 21 Plot the precision check result on a control chart Complete the precision check data sheet This procedure describes the typical calibration operation If the instrument manual describes sp
156. nstrumental recording parts specifications To carry out emergency Wh 1 Detection of failure and en check against emergency repair Emergency f serious ee abnormality 2 Investigation of the causes check failure To recover from and repair ask for os occur missing data period manufacturers 3 Periodical check Periodical check is to check the parameter that affects the precision and condition of the instruments and it needs full knowledge of the instruments in order to carry 121 Manual for Air Concentration Monitoring out the calibration which assures the measurement precision of the monitor and replace the deteriorated parts in the instruments Therefore the periodical check is usually carried out by the maintenance contractor dispatched from the manufacturers Because the frequency of replacement of parts and the measurement precision check may be different for station by station the responsible person should consult with the maintenance contractor about the contents of periodical check 4 Emergency check Emergency check is to investigate the cause of instrumental failure when abnormalities and failures are found in daily or periodical check Then the failed instruments are repaired as much as possible by emergency repair It is also important to reduce mission data period but the very high skillfulness and knowledge are required because this kind of trouble cannot be easily resolved Usually the r
157. nt for avoiding leakage to the outside of the station 3 Handling of compressed gas A gas cylinder shall be kept safely Detailed information is available in the 17 Manual for Air Concentration Monitoring Section 2 2 2 4 and 7 in this manual 4 Safe consideration at routine check and maintenance The measure against handling of toxic substances such as cleaning fluid should be considered at routine check and maintenance 5 Measures for natural disaster 1 Against earthquake To set the caster of the monitor always in the free position to lay a earthquake proof mat on the floor and to fix the instruments by an anchor bolt should be considered as the countermeasure for preventing the fall of heavy loads such as monitor 2 Against fire It is cautious of the electric leakage due to leaky ceiling etc in usual management Moreover when high pressure gas is used the indicator showing Compressed gases is displayed on the door of the station Other requirements are shown as follows i Preparation of initial fire extinguishing standing of fire extinguisher ii Fire resistance of building iii Subscription to fire insurance for the instruments or the station 2 3 Monitoring frequency For evaluation of dry deposition the sampling period of air concentrations could be longer than one day to one or two week Hourly data are required where diurnal cycles in deposition velocity are to be explicitly monitored The actual measurement i
158. o and first order constants due to thermal expansion and compression of the spectrograph detector unit The width of a single emission line yields the width of the instrument function and therefore the minimal spectral distance between two absorption emission lines that can be positively distinguished from each other with the instrument Offset The mean offset was determined by adding up 1000 scans taken at the minimum integration time 100 ms at dark conditions The offset signal was measured routinely at least once in the lifetime of a lamp Neither a clear trend of the mean offset signal 67 Manual for Air Concentration Monitoring with time nor a dependence of the residuals or detection limits of the evaluation procedure on the offset level or structure could be found Dark current The dark current are determined by the measurement of a spectrum with an integration time of 300 seconds with a single scan in dark conditions The resulting dark current spectrum contains only the signal generated by thermal transitions of electrons in the conducting layer These structures are due to a thin layer of water and dirt that remains after the evacuation or leaks into the detector by leakages and then freezes on the surface of the PDA Besides their effect on the dark current structures due to dirt in the PDA have a strong influence on residuals of the fitting algorithm Residual Noise The residual noise of one spectrum consists of
159. o drive the 6 digits display on the front panel The digital analogue board converts the digital data representing the measured ozone concentration into analog voltage 1 V full scale I O buffer board acts as the interface between the zero span status relay board and the microprocessor board The remote control signals for the internal ozonator are encoded on this board and passed to the microprocessor for action 3 1 3 2 O calibration procedures 1 Traceability organization The standard reference photometer SRP made by National Research Institute of a standard and technology NIST performs international comparison periodically and is internationally made into the standard Ozone concentration at a monitoring station is By Manual for Air Concentration Monitoring determined based on the traceability organization by the SRP However it is physically difficult to calibrate all the ozone monitors with the primary standard ozone monitor So the secondary standard monitor calibrated by the primary standard monitor is prepared and also the transfer standard monitor calibrated by a secondary standard monitor is prepared and the ozone monitor installed in each monitoring station is calibrated using the transfer monitor The transfer monitor enables the display of minus and 0 1 ppb It also needs to have a temperature and pressure compensation function Moreover it is desirable that zero point measurement by supply of the zero gas fro
160. o prevent the electrical overload the electric capacity of the station should be ensured with enough margins 2 Outlet for instruments The power distribution to each instrument should be supplied by a three line grounding type outlet effectively controlled by a switchboard A preliminary outlet utilized for inspection and a waterproofed type outlet for outdoor measurements connected to the short circuit breaker etc are also recommended to be equipped 3 Outlet for an air conditioner When the instruments are connected to the power supply system with large load variation such as that for an air conditioner the instruments will receive a noise from the system Therefore the electric power for the air conditioner should be supplied from the other system than that for the instruments 2 Equipment against thunderbolt The station in which the panzer mast for meteorological instruments is installed has the higher risk of thunderbolt To prevent the damage of thunderbolt to the electric facility comprehensive measures are necessary including the installation of a thunder proof transformer a surge arrester a lightning rod and grounding 1 Thunder proof transformer surge arrester It is desirable to install the thunder proof transformer or arrester at the high risk areas for thunderbolt 2 Grounding When the grounding electric outlet is not installed installation of grounding with the resistance value less than 100 ohm is recommended for ke
161. of potential sources of contamination of samples on three different scales Maps of the site and potential contamination sources should be provided to the NC On site scale Description of the on site scale is given for the area within a radius of 100 m from the site Locations of automatic monitors a filter pack instrument and meteorological instruments should be given Trees overhead wires buildings and other physical obstacles should be also described Ground cover and slope and farmlands etc are also important factors Pictures of the monitoring instruments and their surroundings should be attached Seasonal specific condition such as snowfall dust storm and seasonal variation of site conditions should be reported Local scale Surface storage of agricultural products fuels vehicles parking lots or maintenance yards and feed lots dairy barns or a large concentration of animals within a radius of 100m 10km should be described Urban areas will be also described with population Regional scale Both stationary and mobile emission sources within 50 km should be described with 130 Manual for Air Concentration Monitoring emitted chemical species and emission intensities Urban areas with population greater than 10000 should be described Near meteorological stations should be described on the map with available information 2 Sampling condition Automatic monitors The following should be reported mo
162. of the pre determined value Zero value of the instrument Lower limit within 2 of the maximum scale value Upper limit within 4 of the maximum scale value SPM Almost equivalent to PM7 Span of the instrument Lower limit within 4 of the pre determined value Upper limit within 10 of the pre determined value Zero value of the instrument Lower limit within 5 yg m Upper limit within 10 ug m Note Lower limit means the minimum value that needs adjustment Upper limit means the maximum value that can be adjusted 7 6 Determination of accuracy and precision 7 6 1 Point measurement 7 6 1 1 SO precision check procedure A precision check should be performed at least bi weekly The result of 0 09 0 01 ppm level in a dynamic calibration can be used as a precision check result Manual method on site 1 The test gas for precision check can be generated by bottled gas and dilution by calibrator If practicable the test gas should be fed into the analyzer through the sample intake manifold and particulate filter of the analyzer 142 2 3 4 5 6 7 8 Manual for Air Concentration Monitoring The analyzer should remain at normal operation mode Activate the precision sequence from the data logger Check that the calibrator e g Model 146 Thermo Fisher Scientific Inc delivers a SO2 test gas concentration preferably between 0 08 and 0 1 ppm Allow 20 minutes to stabilize Record the true c
163. official approved values or by periodically calibrated thermometer and hygrometer once in 6 12 months The data of the thermometer and the hygrometer are recorded on the internal memory of the PM automatic monitor in many cases The recorded data are useful to check whether the dehumidifier system has worked exceeding the usual range and to judge the reliability of measured values The detailed specifications of each dehumidify method is described as follows 1 Heating method It is the method for decreasing the relative humidity by heating of the sampling tube from the inlet to the detector with a heater The following three methods are adopted depending on the model A The relative humidity inside of the sampling inlet or near the filter is measured by the sensor and then the humidity is controlled to achieve the value less than or equal to the predetermined 35 40 50 etc by heating B The sampling tube is always heated at the fixed temperature 35 C or 45 C C The sampling tube is heated when the humidity exceeds the certain value Since the mass loss is possibly caused not only by the evaporation of the moisture but also by the volatilization of the semi volatile compounds depending on heating temperature necessary to control temperature sufficiently The schematic diagram of the dehumidifier system by the heating method is shown in Fig 3 20 Manual for Air Concentration Monitoring Sampling inlet Sampli
164. on by the blower However this method is not used for PM monitoring in which the sampling inlet and the particle collector shall be present on the vertical line as shown in the previous section Trap of catching insect Sampling in Turbo fun let Distribution inlet Net of preventing insect Figure 2 2 Example for a manifold _15 Manual for Air Concentration Monitoring Fig 2 2 shows the structure of the manifold used generally If the manifold inlet is narrow the monitor inlet may become negative pressure Therefore it is desired that the inner pressure is measured at the time of installing the manifold or extending the monitor 3 Material of sampling tube The materials of the sampling tube for the individual sampling method or the tube connecting between the manifold and the monitor should be selected taking the property of measurement species into account Table 2 1 shows the property of measurement species and the material of sampling tube Table 2 1 Property of measurement species and recommended material for sampling tube Property to be a problem Measurement Recommended materials for in collection process species sampling tube Large adsorption SO2 NOx Polytetrafluoroethylene Hard glass Easily decomposition O3 PM 0 Vinyl chloride Large adhesion loss f PM 25 Stainless steel Aluminum alloy etc 4 Frequency of cleaning or replacement of sampling tube
165. on of effects on air concentrations e Specific meteorological data e Climate rainy and dry season season of sand storm volcanic condition etc e Vegetation the type of tree season of pollen dispersion etc e Life style agricultural operation biomass burning etc 2 Information on the precision of monitoring results e Conditions of monitoring instruments calibration methods failure and incidents on instruments maintenance conditions etc e Laboratory condition maintenance conditions for ion chromatography instrument list chemicals etc 6 2 Compilation of raw monitoring data The data to be reported to NAM are grouped into two types 1 Information about sites monitoring condition shipping of the filter pack samples laboratory operation chemical analysis etc 2 Measurement results of air concentrations by automatic monitors and the filter pack methods measurement results of meteorological parameters and other parameters required to calculate dry deposition fluxes Remarks and notes also compose major parts of the measurement results 126 Manual for Air Concentration Monitoring 1 Information about sites sampling shipping laboratory operation chemical analysis Name of country and site Code of country and site Name of NAM Name of responsible laboratory and PCL Code of laboratory Information of site on site scale local scale and regional scale Information of monitoring condition a
166. on of the filter pack for long duration samplingof ambient air Atmospheric Environment 33 2187 2202 Matsuda K Fukuzaki N Maeda M 2001 A case study on estimation of dry deposition ofsulfur and nitrogen compounds by inferential method Water Air and Soil Pollution 130 553 558 Mehlmann A Warneck P 1995 Atmospheric gaseous HNOs particulate nitrate and 113 Manual for Air Concentration Monitoring aerosol size distributions of major ionic species at a rural site in western Germany Atmospheric Environment 29 2359 2373 Norwegian Institute for Air Research 2001 EMEP Manual for Sampling and Chemical Analysis 301p Torseth K Hanssen J E Semb A 1999 Temporal and spatial variations of airborne Mg Cl Na Ca and K in rural areas of Norway Science of the Total Environment 234 75 85 Viet P H Tuan V V Hoai P M Anh N T K Yen P T 2001 Chemical composition and acidity of precipitation A monitoring program in northeastern Vietnam Water Air and Soil Pollution 130 1499 1504 World Meteorological Organization Global Atmosphere Watch 1997 Report on passive samplers for atmospheric chemistry measurements and their role in GAW World Meteorological Organization 30p Yokohama City Research Institute of Environmental Science 2010 Protocol for NO NO2 SO2 O3 and NH in ambient air measurement using the passive sampler in short term exposure the revised edition 20p in Japanes
167. oncentration and analyzer response values into the precision report form and get a data print out for record Calculate the adjusted analyzer response and record it into the data log sheet Confirm the analyzer and data logger are back to normal operating conditions Ensure the first 10 to 15 minutes reading immediately after precision check is invalidated Complete the precision check data sheet and record the percentage difference Check whether precision check result exceeds 20 Plot the result on a control chart Automatic method 9 Normally the precision check is being done automatically once every two weeks Therefore staff should check the daily calibration summary and complete according to the above steps 4 to 8 at office 7 6 1 2 NOx precision check procedures Manual method on site The precision check should be performed at least bi weekly The result at the precision check concentration of a dynamic calibration can be used as a precision result to replace a routine precision check if desired 1 2 3 The ozonator and the MFCs of the calibrator e g Model 146 Thermo Fisher Scientific Inc should have been certified and the settings suitable for a precision check selected The gas produced by such a setting would produce precision check gas of about 110 ppb NO 90 ppb NO2 The operator just has to set the calibrator Disconnect the analyzer from the manifold and then connect to the output port of
168. onitoring and Dry Deposition Flux Estimation Currently no technical manual for air concentration monitoring has been produced by EANET although the NC has produced the Technical Document for Filter Pack Method in East Asia which was adopted by SAC in November 2003 and QA QC Program for the Air Concentration Monitoring in East Asia published in 2001 In order to obtain comparable and reliable dataset the standardization of air concentration monitoring methodology and development of technical manual should be promoted The standardization should agree with those in other monitoring networks in US and Europe Current specific monitoring methodologies adopted by participating countries should be taken into consideration for the standardization of air concentration monitoring The Task Force on Monitoring for Dry Deposition proposed to establish an Expert Group on Preparation of the Technical Manual for Air Concentration Monitoring composed of relevant experts in this field The establishment of the Expert Group was approved by the Eleventh Session of the Intergovernmental Meeting IG11 held in November 2009 The Expert Group had considered current country specific monitoring methodology of air concentration monitoring and necessary calibration procedures for the automatic monitors and prepares a Technical Manual for Air Concentration Monitoring for EANET 1 2 Objectives Considering the background described in the Section 1 1 the Expert Group rev
169. onsidered to adequate for the participating countries 136 Manual for Air Concentration Monitoring Table 7 1 Data quality objective values for required accuracy precision and completeness unit Accuracy Precision Completeness Within 15 Within 15 More than 70 of for the certified values determined by annual and monthly of the inter laboratory duplicate data samples measurements 7 2 1 Detection limits and reporting limits for air concentration data Detection limits for individual species depend on specification of instrument or procedures of sampling and analysis The NC set up the reporting limits as shown in Table 7 2 taking into account methods adopted by each country Data under the detection limit were treated as N D in the tables of the report Regarding the particulate matter components measured by filter pack method the detection limits for particulate matter components were determined as 0 01 g m for sampled air volume of 20 16 m considering the value of 30 where o is the standard deviation of blank values obtained at Japan sites since 2003 EANET 2003 Table 7 2 Data quality objective values for the reporting limits Species Detection limits Averaging time SO 0 1 ppb 1 hour Auto 1 week Manual HNO 0 1 ppb 1 week HCl 0 1 ppb 1 week NH 0 1 ppb 1 week NO NO2 NO 0 1 ppb 1 hour Auto 1 week Manual O3 1 ppb 1 hour Auto 1 week
170. or the ambient temperature and the temperature displayed on the monitor Moreover it should also be kept in mind for the operator that temperature around the unheated sampling tube is almost the same level as the ambient temperature In the periodic maintenance the displayed values of the thermometer and the hygrometer of the dehumidifier system should be confirmed by the comparison with the thermometer and the hygrometer which are officially approved or calibrated As for the type A and B by the parallel measurement with the reference thermometer or the hydrometer whose sensor is set near the detector it is recommended to confirm 50 Manual for Air Concentration Monitoring that temperature and humidity around the detector is almost same as the setting value In the case of the type C the outputs of the thermometer or the hygrometer for ambient air are confirmed to be almost same as the values of the official approval or calibrated thermometer or hygrometer When the data confirmation results in re adjustment the monitored values after the last maintenance should be verified and judged their adoption If those values are adopted as the reference value or accepted after correction by using any correction equation it is always necessary to put the note which explains the reliability of those values 2 Diffusion tube method This is the dehumidifier system using a tube made of hygroscopic polymer membrane sulfone compounds wi
171. or this process is the fact that atmospheric spectra often feature absorption structures that are not explained by the mathematical description Such structures might be caused by unknown absorbers or absorption structures in the atmosphere or by structures caused within the instrument due to optical faults nonhomogeneous illumination of the grating and or the PDA All mixing ratios presented in the following are computed from the trace gas column densities obtained in the second evaluation run including the residual reference 3 3 Meteorology 3 3 1 Objectives A weather survey is the important item in order to grasp a natural phenomenon and daily survey is important to understand long term change of an atmospheric state Some ey jy Manual for Air Concentration Monitoring surveys are aimed for grasping change of natural phenomenon in a relatively wide area and other surveys for obtaining the data of an air pollution phenomenon elucidation In the air pollution continuous monitoring it is required to grasp the weather change at short range near the ground from the toxic substances emitted in the air being spread with various forms according to a climate condition Moreover the surveys of variations of local wind direction wind velocity and temperature are also important for the measure against air pollution in an emergency Since the meteorological instrument may be distant from the monitoring station a periodic check for change in
172. oring Network in East Asia 2000 Guidelines for Acid Deposition Monitoring in East Asia Network Center of EANET 25p Acid Deposition Monitoring Network in East Asia 2003 Technical Document for Filter Pack Method in East Asia Network Center of EANET 20p Acid Deposition Monitoring Network in East Asia 2010 Technical Manual for Wet Deposition Monitoring in East Asia 2010 Network Center of EANET 11 1p Ministry of the Environment Japan 2010 Ambient air continuous surveillance manual 6th Edition 366p in Japanese Stutz J Platt U 1997 Improving long path differential optical absorption spectroscopy with a quartz fiber mode mixer Applied Optics 36 1105 1115 153 Manual for Air Concentration Monitoring 8 Conclusions This manual shows guideline of air concentration monitoring in EANET in order to standardize air concentration monitoring methodology In principal each air concentration monitoring sites EANET should follow satisfy the conditions in this manual However some requirements in participating countries will not comply with those in this manual For such case the requirements specific in each country can take precedence unless monitoring data are comparable with those in the other countries In order to develop air concentration monitoring methodology which will fulfill the scopes of EANET some issues should be considered First the conventional NOx analyzer cannot selectively detect NO2 The alternative
173. ork Center of EANET 25p International Organization for Standardization 1998 ISO 13964 Air quality Determination of ozone in ambient air Ultraviolet photometric method 348p Ministry of the Environment Japan 2010 Ambient air continuous surveillance manual 6th Edition 366p in Japanese Norwegian Institute for Air Research 2001 EMEP Manual for Sampling and Chemical Analysis 301p U S Environmental Protection Agency 2013 QA Handbook for Air Pollution Measurement Systems Volume II Ambient Air Quality Monitoring Program 13p 19 Manual for Air Concentration Monitoring 3 Automatic monitoring 3 1 Point measurement 3 1 1 SO monitor 3 1 1 1 Principle of the method Automatic analyzers employing the pulsed fluorescence method are used for SO measurements Inside the analyzer pulsating ultraviolet light is band pass filtered and focused into a fluorescence chamber There it excites SO molecules contained in the air sample into high energy states As these excited SO molecules go back to their initial states a characteristic radiation is emitted The concentration of SO in the air samples is then determined by measuring the intensity of the characteristic radiation Fig 3 1 SAMPLE GAS IN Figure 3 1 Schematic of Operation Principle Pulsating ultraviolet light with wavelength at 190 230 nm is bandpass filtered and focused into a fluorescence reaction chamber SO molecules in the reaction chambe
174. p is not necessary for the model which can display the indicated value of the pressure sensor and to the model in which the differential pressure gauge is built in iii A new filter paper side is sent out a valve is opened fully and then the equipment is operated After the operation of the flow stabilizer is completed the indicated value and the difference pressure initial pressure loss of a floated type variable area flow meter should be recorded iv When the valve is shut gradually and the operation of the flow stabilizer is completed the indicated value and the difference pressure of the floated type variable area flow meter should be recorded v It is confirmed that the setting flow is maintained just before the marginal difference pressure repetition measurement or difference pressure just before stopping vi It is confirmed that a repetition measurement will begin when the marginal difference pressure is exceeded Since the indicated value of the floated type variable area flow meter will vary with atmospheric pressure temperature and density of the sample air the value needs to be converted when the flow meter is used on the condition different from the normal condition usually 20 C 101 3 kPa in which the scale calibration is carried out In addition since some models have a possibility that the rapid change of pressure may damage the protective film of the radiation source and the protective film of a detector openin
175. periods as follows 1 Infant Mortality Period Many failures happen as soon as the apparatus are set because of initial failures during making the instruments 2 Constant Failure Period This is the period of constant failure without initial failure and it could be happen in regular operation 3 Wear Out Failure Period This is the period that many failures happen because of wearing out the apparatus by consuming their parts and themselves It is changed by the lifetime of the instruments and the surrounding conditions 5 3 1 Schedule of maintenance It is necessary to plan a long term schedule of maintenance for example frequency of maintenance calibrations overhauls and replacement of the instruments in order to operate the instruments monitor for a long time in a stable manner by maintaining high level of performance and data quality The performance of the instrument is generally getting worse by aged deterioration Fig 5 2 because of continuous measurements Therefore it is necessary to plan a frequency of the periodical maintenance within appropriate period and to judge each instrument status exactly It is also important to grasp the features of the instruments because each condition is different with its situation and its setting location 119 Manual for Air Concentration Monitoring The performance of new model instrument A l l i i Relative deterioration obsolescence The curve of instrument p
176. ports and railways to minimize these influences Remote sites should be at least 50 km from those large emission sources and 500 m from main road more than 500 vehicles per day It is desirable for remote sites to be located at existing meteorological stations in particular upper wind monitoring stations or in their vicinity b Rural sites Rural sites are to be established for the assessment of the state of air quality in rural areas or hinterlands The monitoring data can be used for instance to evaluate the effects of air pollution on agricultural crops and forests The location of these sites should be selected in areas with minor influence from local emission and contamination sources Therefore rural sites should be sited away from significant stationary and mobile sources and should be free from these influences to the extent possible Rural sites should be at least 20 km from those large emission sources and 500 m from main road more than 500 vehicles per day Some rural sites which generally satisfy the criteria for remote sites may also be used to evaluate long range transport and deposition models of air pollutants c Urban sites Urban sites are to be established for the assessment of the state of air quality in urban areas Urban and industrialized areas and the areas immediately outside such areas can be included The monitoring data can be used for instance to evaluate the effects of air pollution on health impacts
177. pper light path in broad daylight These structures are caused by sunlight being scattered in the light path of the LP DOAS system and collected by the receiving telescope Under constant atmospheric conditions these structures are expected to remain constant over integration time thus the stray light correction would remove these structures too In episodes with changing cloud cover however the optical density of these structures might change substantially Therefore the division of the atmospheric absorption spectrum by its associated stray light spectrum would leave differential Fraunhofer structures that cause increased residuals of the fit To overcome this problem a Fraunhofer reference spectrum was generated and included in every set of references adding up 10 to 20 stray light spectra measured on the upper light path in broad daylight if possible within one or two hours applying the high pass filter logarithm and smoothing leaves only the narrow band Fraunhofer structures that would disturb the fit Fitting procedure For the determination of the trace gas column densities from the atmospheric iy 5 Manual for Air Concentration Monitoring absorption spectra the non linear fitting algorithm was used The following references are fitted to the measured spectra 1 NO cross section convoluted from Voigt et al 2002 HONO cross section convoluted from Stutz et al 2000 HCHO cross section convoluted from Meller and Moortg
178. ption spectrum v High pass filtering application of the logarithm and smoothing of the atmospheric absorption spectrum vi Non linear fit of all references and a polynomial of 5th order to the atmospheric absorption spectrum The evaluation algorithm automatically filtered out all measurement spectra that showed over or under range signal to noise ratios resulting in errors within the fit and assured that all spectra were corrected for the lamp structure even if no lamp spectrum directly associated to the actual measurement spectrum was available e g due to problems with the shortcut system A detailed description of the single steps can be found below Offset and dark current stray light correction Prior to evaluation all spectra were corrected for the offset by subtracting an offset spectrum recorded within one or two weeks prior or after the measurement spectra weighted by the numbers of scans in the measured and offset spectrum The dark current was only corrected for in the lamp shortcut spectra and the atmospheric absorption spectra were corrected for dark current and atmospheric stray light within one step by the integration time weighted subtraction of the atmospheric stray light spectrum High pass filter To remove the broad band structures due to scattering processes and broad band 70 Manual for Air Concentration Monitoring absorption a low pass filter was applied the spectra were smoothed by performing a
179. pump depends on the model the pump is recommended to be replaced once in 1 to 3 years A diaphragm and a packing of the collection part should be exchanged once or twice a year 8 Handling of radiation source and detector The source of ray is a sealed radiation source and the low energy model using the Pm and C is usually used Handling must follow the radio isotopic sources such as law of each country Since a protective film of the radiation source is thin and it is easy to damage sufficient cautions are required for handling Not to damage an emulsion side at the opportunity of cleaning of the radiation source The cleaning should be performed using an airbrush a swab etc with careful attention In addition it is desirable to wear protective glasses and latex gloves for operation since the maximum distance of the source of B ray in the air is about 20 cm for C and is about 30cm for Pm When abnormalities such as a hole and dirt are appeared at the protective film of the radiation source which is directly exposed to the sample air the film should be exchanged As for the model that the aluminum evaporated film is used it needs to be Manual for Air Concentration Monitoring cautious of the corrosion by acidic gas or particle especially In addition the radiation source itself should be exchanged for the model in which there is no radiation source protective film other than the protective film equipped at
180. r Third F2 S04 Cl 0 05 H202 Fourth F3 NH Deionized water Recommended extraction procedure is described as follows 1 2 3 4 5 6 7 8 9 Prepare polypropylene test tubes 50 ml with caps Dunk polypropylene test tubes into the diluted laboratory detergent for overnight and then wash them by water at the first and deionized water at the second and dry them in clean air Mark the sample identification on each test tube such as FO filter with sample number FO filter blank F1 filter with sample number F1 filter blank and so on Put the sample filters into the correspondent test tube In the case of F0 F1 F3 stage samples pour 20 ml deionized water into the tubes in the case of F2 stage sample alkali impregnated stage pour 20 ml H202 solution 0 05 v v into the tubes Shake the sample tubes during 20 minutes for their extractions using a shaker or an ultrasonic bath Pick up the filters from the extracted solutions in the tubes and cover the tubes using exclusive caps Filter the insoluble matters out of the extracted solutions using a membrane filter pore size 0 45um previously well washed by deionized water Keep the sample tubes in the refrigerator Ion chromatography IC is recommended for analysis of the above mentioned chemical components The analytical method should follow the procedures described by _95 Manual for Air Concentration Monitoring
181. r are excited into higher energy states and emit radiation as these states decay A photomultiplier tube converts this radiation into an electrical signal which is then filtered and amplified by the electronics to levels appropriate for display Pneumatic path In normal operation air is drawn into the analyzer through a sample valve Calibration gases zero air and span gas are only fed in during calibration by proper control on the sample and zero span valves A hydrocarbon kicker removes hydrocarbon molecules which interfere with the fluorescence activity Excitation of the SO molecules takes place in the fluorescence reaction chamber Fig 3 2 The flowmeter indicates the flow rate in liter per minute LPM The nominal flow rate is 0 5 LPM A capillary tube restricts the gas flow and creates a differential partial pressure across the wall of the kicker for the hydrocarbons removal A differential pressure of at least 254 Diy Manual for Air Concentration Monitoring mmHg is required to remove all interfering hydrocarbons A vacuum gauge shows the differential pressure within the instrument An internal sample pump provides the driving force to draw in ambient air or calibration gases ZERO SPAN o Figure 3 2 Gas Flow Schematic Optical path REFLECTIVE BANDPASS FILTERS CIRCULAR REACTION BAFFLE VOLUME ee TECTORI ELECTRONICS a mn 4sPHOTO MULTIPLIER TUBE EA TRAI F
182. r Research 2001 Denuders can be rather impractical and are relatively expensive and as filter packs are mostly more operative and less demanding in terms of sampling and sample preparation skillfulness the latter is often chosen However since the filter pack technique is poorer when it comes to separate gas and particle phase only the sum of nitric acid and nitrate and for the sum of ammonium and ammonia are obtained Information on the partition between the gaseous and the particle phases may sometimes be inferred also from filter pack data Denuder is useful to selectively monitor NH3 and there is no automatic instrument for NH measurement This may be meaningful for the areas where the concentration of gaseous ammonia is usually high or where the concentrations of both nitric acid and ammonia gas concentrations are so low that the partial pressure product necessary for ammonium nitrate to be present is not reached The separation of SO2 SO is good in both techniques Consumable denuder has been used in EMEP Norwegian Institute for Air Research 2001 4 2 2 Principle of annular denuder The air is drawn through a series of annular denuders and filters The two first denuders are internally coated with sodium carbonate Na2CO3 and glycerol for the collection of nitric acid and sulphur dioxide the third is coated with citric acid oxalic acid or phosphorous acid for the collection of ammonia Evaporation of the coating layer can be a
183. r concentration is preferable However time resolution of filter pack is one or two weeks described in this manual Therefore adoption of aerosol measurement with shorter time resolution could be desired A Particle Into Liquid Sampler coupled with Ion Chromatograph PILS IC Monitor for AeRosols and GAses MARGA a Gas Particle Ion Chromatograph GPIC a Gas and Aerosol Collector Ilon Chromatograph GAC IC Sulfate and Nitrate Monitors R amp P 8400S and R amp P 8400N and a Semi Continuous OC EC Analyzer Sunset Inc are automated or semi continuous instruments capable of acquiring highly temporal resolution measurements of chemical composition of atmospheric PM 154 Manual for Air Concentration Monitoring Third validity of air concentration monitoring methods described in this manual should be checked by the other monitoring methods Especially PM3 5 is sensitive for relative humidity and thus it is hard to confirm validity in tropical regions Some countries established criteria that each PM3 5 monitor should verified by equivalence of the standard method of weight measurement U S Environmental Protection Agency 1997 Ministry of the Environment Japan 2010 Parallel monitoring of the testing method and standard or verified methods is recommended at the monitoring stations References Kebabian P L Wood E C Herndon S C Freedman A 2008 A Practical Alternative to Chemiluminescence Detection of Nitrogen Dioxide C
184. r is recommended to visit the station no longer than 15 day interval and the new employees should take on the job training from experienced site operators Manual for each analyzer is used as the Standard Operating Procedures SOPs for continuous measurement Here are examples of routine station operation e Sample filter change leak check after filter replacement e Check auto drain in zero air unit e Check chemical zero air scrubbers for moisture e Clean sample manifold e Clean size selective inlet for both PM10 and 2 5 samplers replace sample tape as necessary perform zero flow check e Station temperature 27 C 3 C e Check main gas pressure in calibration gas cylinder e Perform zero span levels check on all analyzers e Verify meteorological sensors are operational 5 3 Maintenance of automatic monitors It is important for the routine monitoring to operate an automatic monitor for a long time in a stable manner for maintaining high level of performance and data quality The purposes of the routine monitoring are defined that it was necessary to obtain the effective data above 70 in day month and year such as above 16 hours in day above 504 hours in month and above 6132 hours in year It is described in Section 7 2 in detail For the attainment of these purposes a monitor should be maintained fundamentally according to two methods as follows i Preventive maintenance the methods to maintain preventively to the parts
185. r paper of the low volume air sampler it is recommended to use tetrafluoroethylene resin Teflon filter quartz fiber filter or glass fiber filter with surface treatment processing And those filters are required to fulfill the following condition initial collection efficiency of 99 7 or more for 0 3 um particle low initial pressure loss little pressure loss in particle collection little hygroscopicity little absorption of acidic gas sufficient strength on handling Size classifier should be used in the clean condition to prevent the change in the size classification characteristics iii The low volume air sampler used for the check should be beforehand calibrated with the standard flow monitor iv In addition as for the model which uses a finite difference pressure valve it should be used after the adjustment and the confirmation that the actual flow rate is maintained in 20L min until the marginal difference pressure v For the model required the correction of the indicated value according to the increase in difference pressure and the sample air temperature the sample collection shall be done in the manner that the actual flow rate is always adjusted in 20L min after correction 55 3 2 1 2 Manual for Air Concentration Monitoring Dynamic calibration The mass concentration of the calibration air including the particle for calibration discharged from the particle generator is beforehand measured by the lo
186. rable to that at the calibration iv Little fluctuation of power supply voltage and frequency It is expected that there is no big electromagnetic induction equipment or the generating equipment of spark discharge near the station Take measures against thunderbolt if required v Amonitor shall be installed horizontally against the floor vi Maintenance work for safely and easiness Maintenance and repairs of the monitors may be usually performed from the back side of the monitor For this reason it is desirable to keep the space between the monitor and the wall for making maintenance and repair easily vii Shortening of the sampling tube When the possibility is raised on the adsorption and decomposition of measurement species in the sampling tube the sampling tube should be as short as possible 2 2 7 Safety requirement It is necessary to take proper safety measures at the establishment of a station with careful attention to the following matters 1 Safe considerations to the surrounding residents 1 At establishing station i Entry restrictions into the construction zone ii Electric shock preventive measures during the construction iii Traffic safety guidance to the construction vehicles 2 At working Electric shock preventive measures to the surrounding residents after starting the operation 2 Prevention measure to the toxic substance leakage Toxic absorption solution and spare parts should be stored with carefully arrangeme
187. ration Monitoring 2 Installation criteria Basically the hygrometer should be place as the same condition of the thermometer described in of the Section 3 3 3 The installation height is 1 5 above the ground In general a hygrometer is placed in a Stevenson screen whereas it should be placed in a small type screen equipped with the ventilation device if the space is limited When an electrostatic capacity type hygrometer is used it is stored in the vent sleeve by together with the thermometer 3 Maintenance protocol 1 Daily check Daily check should be conducted according to each observation method A Electrostatic capacity type hygrometer The dirt of the membrane filter which protects the sensor is checked When sea salt particle dust or smoke is deposited on the filter it is removed from the sensor unit and washed by distilled water then dried in air B Dew point type hygrometer At heavy polluted area and coastal area the frequency of LiCl replacement would be more Therefore it is important to conduct comparison measurement between the Assmann Type Psychrometer and the hygrometer C Hair hygrometer The dirt of hair is checked and it is carefully cleaned with a feather to remove sand and smoke etc When the dirt is remarkable or it is used for several months the hair should be cleaned by using a brush immersed with distilled water and then dried in air 2 Periodical check Because the maintenance requires skillfulness and specifi
188. ration time of the filter pack and other manual monitoring 4 Meteorological Parameters Wind Speed with the unit of m s Wind direction Temperature with the unit of C Relative Humidity with the unit of Solar radiation with the unit of MJ m Precipitation with the unit of mm Duration time of meteorological measurement If data are flagged or failed results corresponding cells must be kept the blank The reporting form should also include sampling conditions date of chemical analysis and other remarks An example of the data report form is shown in Table 6 1 6 3 Each national center should keep all the raw measurement data for future reference 6 5 Data storage Primary monitoring data such as chart recorder data digital data with high time resolution analytical data of manual monitoring should be kept in the responsible organization at least for 3 years These data should be provided for data validation and further air concentration analysis upon request Statistics data of monthly and annual mean concentrations will be prepared by the NC 132 Manual for Air Concentration Monitoring produce of data base of air concentrations in EANET sites Hourly data for automatic and reported in EANET data report after validation and finalization The NC will monitors and highest time resolution data for manual monitoring will be provided depending on EANET data disclosure policy A oh Gie sez zo ro 00 2 T
189. rge carriers reduce the applied inverse voltage The voltage is also reduced by the transition of thermally activated electrons into the conducting layer This dark current effect must be considered in the evaluation procedure especially at low light intensities In order to reduce dark current which de creases exponentially with decreasing temperature the PDA was cooled down As the dark current depends also on the integration time an integration time corrected dark current spectrum is subtracted from every atmospheric spectrum during the evaluation procedure After the PDA has been read out the signals are electronically amplified To exclude negative signals under low light conditions an offset signal is added to every PDA signal As the final spectrum can be composed of a number of single scans it is obvious that the offset correction of the final spectra must be performed with respect to the number of scans Spectral resolution of the instrument To compute the spectral resolution and the dependency between diode number of the PDA and the wavelengths emission spectra of Ne and Hg high pressure lamps are recorded Fitting a polynomial of second order to the central wavelengths plotted against the corresponding diode numbers of the line centers yields the dispersion relation as shown in the equation 3 17 A j 374 41 nm 0 0375 nm j 8 3 x 107 nm j 3 17 which slightly changes with time in shift and squeeze i e in the zer
190. rge volume samples should be divided into two aliquots one half for immediate routine analysis and the other should be immediately refrigerated and stored at 4 C and analyzed in less than 7 days as part of another analytical run Analytical precision is defined as the standard deviation between the two analyzes S Xd 2 2N 1 2 7 1 where d denotes the difference between the two measurements and N is the number of the sample pairs for the duplicate analysis in the reporting period The factor 2 is included in the denominator to account for the random error associated with both measurements 2 Accuracy of chemical analysis The accuracy of analytical measurements is evaluated by analyzing simulated filter samples referred to as inter laboratory comparison samples Within EANET the inter laboratory comparison samples of dry deposition are prepared using reagent grade chemicals supplied to all analytical laboratories by the NC on an annual basis Analytical performance is evaluated using the data from the chemical determination of the inter laboratory comparison samples Statistical analysis and control charting of the results is helpful in identifying deficiencies and finding solutions to analytical issues and will result in an improvement of data quality 3 Definition of not detected and lowest determination limit The measurement is not always addressed by a definite number For example some analytes may be not detected or
191. rmed The outputs of the pre amplifier of the NO and NOx channels are level shifted by the mixer board The signals are then amplified by a variable gain amplifier As the chemiluminescent emission is chopped by a mechanical interrupter synchronizers are needed to synchronize the processing of signal with the chopped emission The outputs of the synchronizer are filtered to minimize noise The filtered signals are further amplified and level shifted by a variable gain amplifier based on the settings of the SPAN and ZERO pots on the analyzer front panel The final output of the NO channel is subtracted from that of the NOx channel to obtain a signal corresponding to the nitrogen dioxide NO 2 concentration The concentration of nitric oxide NO nitrogen dioxide NO2 and their summation NOx can be displayed by proper setting of the METER selector on the analyzer front panel The range divider converts the signals to 0 1 V DC analogue outputs for recording purpose The mixer board power supply T1 the HVPS output T2 and the pulse detecting amplifier output chopper speed T3 can also be displayed on the analogue ammeter by proper setting of the METER selector 3 1 2 2 NOx multi point calibration procedures The calibration of the NOx analyzer consists of two parts 1 evaluation of the characteristics of the NO and NOx channels by dynamic dilution of a standard gas and 2 evaluation of the characteristics of the NO channel by
192. rotocol i Hourly data should be effective when more than 3 4 of the data during the 127 Manual for Air Concentration Monitoring measurement period is effective ii The ending time should be used for the hourly data e g hourly data for 1 p m should be the data between noon and 1 p m expressed as local time of each country iii Hourly average should be calculated as the arithmetical mean of the sum of the data except non usable ones divided by the effective duration Daily average should be the value calculated as the sum of the all hourly data from 1 a m to 12 p m excluding the non usable hourly data divided by effective hours of the day Daily average should be used only when 3 4 of the hourly data of the day is effective iv Monthly annual average should be calculated as the sum of the hourly data of the month year divided by the effective hours of the month year Therefore it should not be the average of the daily averages v Non usable data should be the data that are not considered adequate due to such reasons as the maintenance calibration or breakdown of the instruments Non usable data should not be used for statistical treatment but should be reported with flags vi Annual average should be calculated by using the data from January through December of the year 6 3 Data validation Data checking or validation is based upon e Experience with the data from earlier measurements e Knowledge abou
193. roubleshooting parts supply and recording Management of reagents standard materials etc 1 Appointment of management staff and their supervisors 2 Receiving and disposal of reagents recording format of dates manufacturer names dealers purity degree of standard and valid period 6 External audit 5 2 1 Check of sampling sites 2 Measurement of field blank values 3 Operation check of samplers and instruments 4 Evaluation of the results of quality control 5 Evaluation of the measured results Maintenance in a monitoring station Station maintenance is a portion of preventive maintenance that does not occur on a routine basis These tasks usually occur on an as needed basis The station maintenance items are checked monthly or whenever an agency knows that the maintenance needs to be performed Examples of some station maintenance items include Floor cleaning amp vacuuming Shelter inspection AC filter replacement replace battery in remote control Weed abatement Inspect roof mounted equipment Inspect meteorological sensors and cables Verify true north orientation for wind direction 117 Manual for Air Concentration Monitoring e Ensure UPS operates in excess of 30 minutes e Ensure there are operating schedule for each monitor e Ensure a copy of the manual for each analyzer is kept in the air monitoring station and at the maintenance contractor Routine station operation The operato
194. ry to be in the range of 1500 to 6000 Kcal h 6 Inlet of cable for meteorological monitor and electric power supply It is necessary to equip intakes for a cable that connects meteorological sensors and recorders a cable of a power supply and a cable for data extraction system 7 Safety facility for compressed gases Storage and consumption of compressed gases should be carried out as follows i iii yi Do not use the fire within 2 m from the storage of compressed gas cylinders when the effective shielding measures such as concrete barriers are not taken To inform the location of the storage attach a sticker indicating compressed gases at the entrance of the storage Fix the compressed gas cylinder except less than 5 L with a stand to prevent shock and damage to a gas regulator by overturning of the cylinder Always keep the compressed gas cylinder at temperature less than 40 C Installation of fire extinguisher is desirable Carbon dioxide fire extinguisher is recommended Although the compressed gas cylinder of nonflammable gases can be placed in a main room of the station it is desirable to construct the cylinder storage looker at the outside of the station for facilitating the cylinder exchange and safety measures in the station A locker is recommended to maintain ventilation with the open air for safety and combustible gas must keep away from oxygen and the other reactive gases Cylinders should be fixed by a be
195. s is considered to be significantly above the background noise Thus the detection is always directly linked to the noise level and no general detection limit exists It depends on the quality of each measurement if the absorber can be identified But still a detection limit for a specific noise level can be given There are two methods to estimate the detection limit of DOAS measurements 1 Detection limit from measurement error In order to obtain the detection limit for DOAS measurement statistical considerations are used Assuming the measurement being subject to Gaussian error statistics the retrieved measurement error can be used to calculate the detection limit As the measurement error calculated from the statistical fit error gives the 1 o range of a 150 Manual for Air Concentration Monitoring measurement the true measurement value is in this range with a probability of 68 If the DOAS measurement also contains beside statistical errors systematic errors which do not follow Gaussian error statistics this 1 o range can be used if the error is corrected with the factor C The 2 o confidence interval with a probability to find the measurement true value within 95 is obtained by multiplying the error by 2 If the 2 o interval is entirely located above null and thus the determined concentration is larger than the 2 o value than the measurement has a probability of more than 95 of being above null Usually this is con
196. s not generate any gases disturbing measurement shall be used When the sampling tube made by the plasticized polyvinyl chloride or the copolymer of ethylene and VCM PVC is used at the temperature of 40 C or more it is reported that the particulate matter is discharged from the tube and it causes a positive error iii Length of sampling tube The sampling tube should be installed in a vertical direction from the monitor The tube is also recommended to be a straight and its length should be as short as possible iv Frequency of changing sampling tube The proceeding dirt induces the adhesion of particulates on the inner wall of the tube and causes the reduction of measurement accuracy For this reason a sampling tube should be washed or replaced periodically Although the frequency of washing or replacement depends on the situations of the measurement site it is required to carry out once or twice a year at least v Particle size classifier The PMjo and PM gt 5 monitors are recommended to have particle size classifiers whose 50 cutpoints are 10 0 5um and 2 5 40 2um aerodynamic diameter respectively The classifier is also expected to have the character which the ratio of 80 cutoff particle size to 20 cutoff particle size is equal to or less than 1 5 for PM3 5 and is about 2 2 for PMio respectively Ministry of the Environment Japan 2010 and U S Environmental Protection Agency 2014 Since the cyclone type particle size classifier cha
197. sidered as significant detection of a certain species The 3 6 confidence interval would give a detection probability of 99 7 2 Detection Limit from Fit Residual If the optical density of the residuum is small compared to the trace gas absorption derived in the fitting procedure the respective trace gas may certainly be detected Thus another method to estimate detection limits of the DOAS instrument is the evaluation of the fit residuum The assumption is made because the DOAS instrument cannot measure any trace gases whose absorptions structures are smaller than the current fit residual AY S a Sa ELAY 7 14 max min Differences arise in the rating of the absorption structure compared to the residuum A worst case approximation is using the peak to peak value Pinax 7 F min j as AY A more realistic approximation uses twice the average deviation from the mean value in the wavelength interval of the considered trace gas absorption band Since the depth of trace gas absorption structures is a direct function of its differential absorption cross section S its average concentration c and the observed path length L are the only parameters theoretically limiting the detection limit beside from the photon noise The minimum detectable average concentration is therefore AY i Shax S hin L 7 15 7 7 QA QC implemented by the NC The NC should appoint the network QA QC manager who is responsible for managing overall
198. site and returned to the laboratory without being exposed at the site Denuders and filter holders will have been prepared and should be transported to the sampling site in special transport containers They are to be connected to the sampling equipment according to specific instructions and should be marked with the sampling date and time period start and end and the type of denuder number D1 D2 D3 in the laboratory before transport to the site Make sure that connections are leak proof The sampling period identification of denuders and filterpacks gas volume meter readings and notes of observations should be recorded in the field note for the evaluation of the results The denuders and filter packs should be capped after exposure and put in the container used for transport to the chemical laboratory together with the field blanks It is suitable for the determination of nitric acid and ammonia in the concentration ranges 0 50 ug m HNO3 N and 0 5 ug m NH3 N respectively for weekly monitoring If the air concentration levels are expected to breakthrough of the denuder the sampling period must be modified 3 Chemical analysis The preparation of samples for chemical analysis is shown as follows D1 NaCl imp Extraction with 10 ml deionized water D2 NazCO3 imp Extraction with 10 ml deionized water with H202 0 3 D3 Citric acid Extraction with 10 ml deionized water F1 aerosol filter Extraction with 10 ml deionized w
199. sorption in dependence of the wavelength is characteristic of each compound like a fingerprint In 1979 Differential Optical Absorption Spectroscopy DOAS was introduced to measure atmospheric trace gas concentrations using an artificial light source Platt et al 1979 Since then DOAS has been applied to measure trace gas concentrations in the troposphere and stratosphere as well as under simulated atmospheric conditions Several important atmospheric trace gases such as OH HONO NO3 BrO IO were measured for the first time using DOAS Then a large number of other molecules absorbing the light in the UV and the visible wavelength region e g NO2 NO NH3 ClO O3 SO CS HCHO etc have also been detected Platt 1994 DOAS is a very sensitive measurement technique for these trace gases since they exhibit strong and highly structured absorption cross sections in the UV and visible spectral regions Because DOAS is capable of measuring trace species in the open atmosphere it is especially useful in the detection of highly reactive species such as the free radicals OH NO3 halogen oxides CIO BrO IO etc The simultaneous determination of the concentration of several trace gases by analyzing the sum of their absorptions in one wavelength interval reduces measurement time and allows analysis of the average chemical composition of the observed air mass with high temporal resolution Several types of DOAS are shown in Fig 3 23 The LP DO
200. st the roof side at which a downward wind produces iii The standard height of the support which attaches a transmitter is 0 35 or more times of the height of the building 2 Setting of direction It is necessary to decide the exact direction of south and north in the case of installation of a wind direction anemometer as shown below A By using a magnet compass Compass is put on the place which is not close metal and ferroconcrete buildings and does not have disorder of geomagnetism The direction of N is temporarily appointed at north and then the gap angle of north and magnetic north should be corrected In north east Asia the deflection angle the west deflection can be determined by the following empirical formula calculated from the latitude and longitude of an observation place D 7 5 45 21 03Ag 5 84A1 0 360Ay7 0 274A 9 AI 0 470A17 3 20 D the west deflection angle Ag 9 37 N denotes latitude in degree unit Ad A 138 E A denotes longitude in degree unit B By using the high resolution map Prepare the high resolution local map and the object on the known azimuth line as far as possible from the anemometer is defined on the map Then the direction is set according to the object C By using the solar position There are two methods One is to determine north and south by the shadow made by hanging a weight exactly at noon Another is to determine the true azimuth by the special measurement equipment on a flat plate
201. t Leak check should be done every time before open the valve The staff in charge of safety management should open and close valve slowly and carefully The pressure of gas cylinder should be recorded every time ajz Manual for Air Concentration Monitoring and if the remaining pressure of gas is lower than 0 5 MPa the cylinder should be replaced It means that the gas should remain at least 0 5 MPa Name and valid date and other information should be labeled on the cylinder The valid date of cylinder and valve should also be recorded and make sure to use both of cylinder and valve within valid date Some gas cylinders should use special valve for example it is better to use red color valve for the Hydrogen cylinder 5 6 2 Disposal of chemicals solution waste and monitoring instruments The acid and alkaline waste solution should be mixed and collected in waste tank and then neutralized by acid or alkaline solution until pH value ranges from 6 to 9 before throwing away The name of waste solution should be labeled on the tank Avoid direct sunshine to the waste tank The common acid and alkaline chemical used for neutralizing are hydrogen chloride HCl and carbonate calcium CaCOs The treatment of B ray detector has already been mentioned in the sector of B ray monitoring method The low level of radioactive substance should be stored in special tank with specific label describing the half life period References Ministry of the
202. t observation results Therefore unless the observed values are obtained under the same conditions comparison of the data is difficult In the case of air monitoring stations there are few cases attain the stable condition so one must be careful to use the temperature data The unit of the temperature is C and to be recorded up to 0 1 digits There are a number of types of thermometer but the electric resistance type thermometer using a platinum thermo sensor is used for the air monitoring station 1 Principle of measurement A platinum resistance temperature sensor is used for the electric resistance type thermometer This sensor utilizes the principal that metal resistance is changed by temperature Temperature can be determined by measuring electrical resistance The platinum resistance temperature sensor is formed of a coiled platinum wire of diameter approximately 0 1 mm around a thin mica or porcelain board and the sensor is placed in a protective stainless steel tube which is completely waterproof The platinum resistance thermometer has the 3 line type and the 4 line type which are developed for eliminating interferences of platinum resistivity 2 Installation criteria Manual for Air Concentration Monitoring The thermometer should be installed on the opened lawn ground where there is no shade of buildings and trees The ground should be treated as good water drainage A wooden Stevenson screen or a vent sleeve is ins
203. t air sample A mechanical chopper is used to interrupt the chemiluminescent emission from the reaction cells at about 87 times per second in order to maintain stability The chemiluminescent energy is emitted in full view of the photomultiplier tubes through the optical cutoff filters in each reaction cell The outputs of the two photomultiplier tubes corresponding to the concentration of nitric oxide NO and the total concentration of nitric oxide NO and nitrogen dioxide NO2 are then filtered and amplified by the electronics to levels appropriate for display Their difference is also electronically calculated so as to obtain the concentration of nitrogen dioxide NO2 in the air sample Pneumatic path In normal operation air is drawn into the analyzer through the sample port of the controller Calibration gases zero air NO and NO span gas are fed in only during calibration A Teflon filter removes particulates from the incoming air stream The incoming air is split into two streams One stream passes through a flow meter and enters the NO cell Fig 3 6 The other air stream enters the NOx cell through the MOLYCON and a flow meter A small 7 mm orifice is present in each of the reaction cells to restrict the flow rate of each air stream to 200 250 cc min as indicated by the corresponding flow meter The life span of a new MOLYCON is in excess of 6000 ppm hrs The ozone required for the chemiluminescence reaction is provided b
204. t spatial and temporal variation in previous years Records of the old data can be used to create simple statistics including percentiles mean values and standard deviations Log transformed data are sometimes considered These statistics can be used in connection with control chart or in other comparisons of new data with aggregation of the old ones Relations between various chemical components including ion balance Ri of particulate matter components relationship between sea salt components and relationship between air concentrations from neighboring stations and time series plots are also useful 6 3 1 Statistical tests The statistical tests are comparisons between new measurement and calculated results and data already stored in the database The tests are carried out to identify possible outliers and results which may be wrong They can be based upon assumption about the data distributions In some cases respective air concentrations and calculated dry deposition fluxes may be compared with earlier data using the lognormal distribution 128 Manual for Air Concentration Monitoring Data which is not within the four times the standard deviations range should be checked by comparison with air concentrations and other results obtained on earlier and later days and results from neighboring sites 6 3 2 Data completeness Data completeness should be evaluated in terms of the flagged or invalid data for automatic monitor
205. t the fixed distance of 20 cm are measured By using the 2 sets of transducers intersected perpendicularly and installing them in the direction of east and west and in the direction of north and south the east west component X component and a north south component Y component of the wind are measured simultaneously and a wind direction and a wind velocity are obtained by the vector composition Moreover some anemometers can perform observation of a three dimensional wind by installing a transducer also in a vertical direction 2 Installation criteria 1 Installation place According to the World Meteorological Organization WMO criteria the wind direction anemometer should be set in the flat and opened place which does not have an obstacle in the surroundings A panzer mast or a support pole should perpendicularly set at the 10 m height on the ground When the height at 10 m is not securable or when the representative place is not obtained it is desirable to select a setting place as follows However convenience of A Manual for Air Concentration Monitoring the maintenance should be considered at the selection of the installation position i The highest place of the roof is ideal and the influence from the structure of the roof should be considered ii The influence of upward blowing near the outer wall of the roof and its circumference should be avoided A transmitter is installed at the angle of 40 degrees or more again
206. tage filter pack is composed of four filters in line with the air stream as shown in Fig 4 1 Aerosols are collected on the first filter FO made of PTFE while 84 Manual for Air Concentration Monitoring the gaseous substances such as SO2 HNO3 HCl NH will pass though this filter The second filter F1 made of polyamide collects all HNO and partial SO2 HCl and NH from the sampling air The remaining SO and HCl react with alkali substance on the third filter F2 made of cellulose Oxidizing species in air such as ozone are believed to convert most of the sulfite to sulfate during the sampling The remaining NH reacts with acid substance on the fourth filter F3 made of cellulose after passing through the first second and third filters Ammonia is effectively retained on a filter impregnated with phosphoric citric or oxalic acid Aerosols are collected on the aerosol filter FO mounted in front of the other filters F1 F2 and F3 collecting gases The material of the aerosol filter should not absorb acid and alkali gases and should have acceptable efficiency to collect sub micron particle because sulfate aerosols are mostly of the fraction below 1 um For this purpose Teflon PTFE polytetrafluoro ethylene filters are preferred Ta filter td gt Acid impregnated cellulose o Alkali impregnated cellulose o Polyamide MOT ITV PTFE Fig 4 1 Schematic diagram of the four stage filter pack 4 1 2 Artifacts of f
207. talled on the observation ground and the thermometer is contained inside 1 The case of using vent sleeve The thermometer is contained in the vent sleeve with the ventilating device The height of the air inlet of the vent sleeve is set to 1 5 m above the ground When it is installed in a building it should be set at the height which is not subject to the influence of reflection or radiation 2 The case of using Stevenson screen The Stevenson screen is made of wood and can protect the meteorological instrument from solar reflection and radiation The leg is buried and fixed on the ground so that the height of leg comes out at 1 m above the ground However in heavy snow areas the leg height must be higher according to snow coverage Moreover the front door should set at north so that sunshine is not be irradiated the inside A thermometer should be installed at 1 5 m above the ground 3 Maintenance protocol 1 Daily check i A piece of paper is brought to the inlet of the vent sleeve to confirm the ventilating device properly working It should be also cautious of the dust and the freeze on the sleeve ii The Stevenson screen should be kept clean from dirt by rain and sand and a cobweb etc iii The external output and recording status are checked iv Comparison test with the Assmann Type Psychrometer should be performed to confirm that the difference between them is less than 0 5 C Because the Psychrometer is affected by sol
208. temperature dependence 203 293 K of the absorption cross sections of O in the 230 850 nm region measured by Fouriertransform spectroscopy Journal of Photochemistry and Photobiology A 143 1 9 Voigt S Orphal J and Burrows J P 2002 The temperature and pressure dependence of the absorption cross sections of NO2 in the 250 800 nm region measured by Fourier transform spectroscopy Journal of Photochemistry and Photobiology A 149 1 7 83 Manual for Air Concentration Monitoring 4 Manual monitoring In order to evaluate the extent of air concentrations in East Asia spatially and temporally a sufficiently long record of data from a dense network of sites distributed over the region is usually required Presently the number of EANET monitoring sites is limited and not well distributed One of the reasons for the lack of air quality monitoring sites in some countries is the high cost of automatic instruments and occasional costs of operating the instruments One of the possible ways to overcome this problem is to adopt the simpler low cost methodologies such as passive samplers Besides mass of atmospheric particles which is measured using automatic method as described in previous chapter the particulate components are also very important for air quality evaluation Filter packs and denuders are the only methods to measure particulate components in this manual The filter pack method is useful for total gaseous and particulat
209. tems can be decided by taking account of the presently available air quality monitoring and feasibility of additional monitoring activities as well This monitoring might employ either of real time monitors or integrating manual samplers filter packs denuders or passive samplers as may be determined appropriate For SO2 for example use of a real time monitor is preferred with data reported so that averages over hourly concentrations can be archived For all chemicals measured specifically for dry deposition applications longer time averages e g weekly or bi weekly would be adequate These can be derived from daily averages if appropriate or from any other sampling protocol that might be desired For the purpose of air quality monitoring one hour averaged values are principally preferred and the availability of commercial or conventional instruments has to be also considered For example automatic instruments for SO fluorescence method O3 UV absorption method and NO ozone chemiluminescence method are suitable to obtain one hour averaged values of these species for air quality monitoring These one hour averaged values can of course be used for the purpose of the evaluation of dry 18 Manual for Air Concentration Monitoring deposition after averaging over longer periods e g for one week References Acid Deposition Monitoring Network in East Asia 2000 Guidelines for Acid Deposition Monitoring in East Asia Netw
210. tems should be taken into account National Center i Preparation of the national monitoring plan ii Preparation and implementation of the national QA QC programs Appointment of the national QA QC manager e Guidance for the preparation of SOPs at relevant organizations laboratories Distribution of inter laboratory samples collection of the results and reporting to the NC e Audits to sites and laboratories Comparison of sampling and analysis methods used in the country iii Collection of monitoring data and reporting of the data to the NC iv Development and implementation of the national training programs Monitoring chemical analysis organizations 1 Appointment of personnel in charge and their supervisors il Preparation of SOPs in respective activities in the organization iii Execution of routine monitoring chemical analysis iv Periodic reporting to the National Center v Participation in QA QC activities conducted by the National Center such as analysis of inter laboratory samples 7 2 Data Quality Objectives DQOs The required data quality objectives DQOs can be different depending on the objectives of different programs The DQO values define the desirable levels of accuracy precision and completeness required by the program DQOs may also differ if the concentration levels are significantly different Considering the present status of the air quality monitoring in East Asia the following DQOs are c
211. th fluorinated polyolefin The sample air and the dry air are circulated to the inside and the outside of the tube respectively and moisture in sample gas is absorbed alternatively and discharged Since it is necessary to take the long passage time through the diffusion tube in principle this method is used for the monitor which has adopted the low flow rate 3 0 L min or 1 2 L min and the high sensitivity detection principle Some models are always operating the diffusion dehumidification tube and the others control the system circulating the dry air when the relative humidity exceeds the setting value This system has some advantages no power supply required high dehumidification capability and small loss of semi volatile compound however it is cautious to have a possibility declining the dehumidification capability if high relative humidity has continued for a long time Moreover it is necessary to exchange parts in a certain fixed period The schematic diagram of the dehumidifier system with the diffusion tube method is shown in Fig 3 21 In the maintenance of the diffusion tube method the tubes should be replaced within one to three years in general However when the dehumidification capacity drops down during the operation it should be exchanged even for less than a year For example a lot of water droplets on the purge filter portion without leakage is caused by the reduction of the dehumidification effect due to the moisture invasion
212. the radiation source Moreover since the counting rate decreases rapidly by the moisture absorption in the air when the Pm radiation source is damaged or a pinhole forms the measure for preventing radiation pollution expansion should be taken immediately and then the radiation sources should be exchanged carefully by asking a manufacturer or a specialized agency Exchange and abandonment of the radiation source must follow the law of each country Pay attention not to touch at the specular surface portion of a semiconductor detector Moreover the plastic scintillation counter should be handled paying attention whether the pinhole is made in the surface of aluminum evaporated film and whether the counter has been corroded by the alkaline water droplet fell from the filter paper of the collection part in high humidity condition 9 Measure against magnetic field Since the B ray is an electron flow with the minus charge and tends to be influenced by a magnetic field it should be avoided to use the magnet which produces the magnetic field around the radiation source and the primary detecting element 3 1 4 2 Tapered Element Oscillating Microbalance TEOM method 1 Principle TEOM is a gravimetric instrument that draws ambient air through a filter at a constant flow rate continuously weighing the filter and calculating mass concentration The weighing principle of TEOM is different from most others The tapered element is in essence a ho
213. the DOAS measurement It is important that this number of photons or number of photoelectrons scans is determined for each instrument Here a short overview of the different noise sources and their mathematical description is given It is followed by an estimation of the absolute DOAS error of a measurement and details on averaging of data points to increase the signal to noise ratio 1 Systematic errors The most important systematic errors are Uncertainties and errors of the literature cross sections Depending on the trace gas of interest the error of the literature cross section is between 1 and 15 Stray light in the spectrometer gives a negative offset to the determined concentration The applied Acton spectrometer 300i and 500i display only very low stray light up to 0 1 and thus this error is very small lt 1 Additional filters may be applied to further reduce the light of the unused spectral range Reflections can also produce stray light like reflection at the detector window All these stray light errors are estimated to be smaller than 3 For the used configuration additional stray light arise due to the simultaneous 147 Manual for Air Concentration Monitoring measurement of absorption spectra from different light paths with one spectrometer detectotion unit It could be found that for some extreme configurations with different intensities this can contribute up to 10 and thus to an error of the
214. the calibrator The analyzer must be operated in its normal operation mode and the precision test gas must pass through all filters scrubbers and as much as practicable all other components used during normal ambient sampling With the MFC settings at precision check and the ozonator off switch on the gas supply and then supply the test gas into the analyzer record the stable responses of NO and NOx into the worksheet Denoted by NO resp and NOx Resp respectively EPES Manual for Air Concentration Monitoring 4 Turn on the ozonator at the setting for precision check Record the stable responses of NO and NOx into the worksheet Calculation 5 Assuming that there is no or negligible NO2 impurity in the bottle gas the concentration of actual NO concentration can be calculated as follow NO 2 Act Adj NO O OFF Adj NO O ON 7 4 Where Adj NO O3 OFF is the adjusted NO response without ozone applied Eq 7 6 Adj NO O3 ON is the adjusted NO response with ozone applied Eq 7 6 6 The adjusted response of the NO channel Adj NO 2 can be calculated by the equation 7 5 Adj NO2 Adj NOx Adj NO 7 5 Adj NO NO resp Zo SF NO 7 6 Adj NOx NOx Rresp Znox SF NOx 7 7 Where Zno ZNox NO and NOx zero readings respectively and SF SGC span zero Zero and span readings can be obtained from the previous night s automatic zero span check or from
215. the formula of concentration C ng L and sampling rate SR L min Wit SR C 4 12 Wit DA CIL DAIL C 4 13 D of NO 0 1567 cm sec at 20 C Where A 0 785 cm L 0 6 cm SR DAIL 0 205 cm sec 12 3 cm min Then C L DA WIt 4 14 Concentration can be expressed by the formula of collection rate W t C a Wit 4 15 Where C concentration ppbv t collection time min W collected weight ng a coefficient ppbv min ng Then l11 Manual for Air Concentration Monitoring a 1 60 1 f 1 D L A V M 10 4 16 Where a coefficient ppbv min ng f coefficient for calculation from gas phase to ion phase D molecular diffusion coefficient cm sec L diffusion length cm A area cm V volume of 1 molar gas L M weight of 1 molar gas g In consequence the concentrations of ambient pollutants are calculated as follows SO ppbv asoz Wso2 t 4 17 NO ppbv ano Wnox Wno2 t 4 18 NO ppbv ano2 Wno2 t 4 19 NH ppbv anus Wnus t 4 20 O ppbv aos Wos t 4 21 where W collection volume of each gas ng a conversion coefficients of each gas ppbv min ng t exposed time min The following coefficients were reported at 20 C 70 relative humidity and 1 atm Yokohama City Research Institute of Environmental Science 2010 aso2 39 4 QNO 57 ano 57 QONH3 87 6 ao3 46 2x107 9 94xIn t 6 53 Coefficien
216. the inlets such as impactor the exact flow rates depend on the devices d Cramp d Shelter Pole Filter pack holder eel a Sampling tube Example A Using Mass flow gt Exhaust mass flow controller controller Pinch cock Example B Using Mass flow Exhaust mass flow meter meter Pinch cock Example C Using gas volume meter i A gt Exhaust 4 Example D Using flow A gt Exhaust meter with regulator and TO gas volume meter Fig 4 2 Schematic diagram of filter pack sampling system 89 Manual for Air Concentration Monitoring A diaphragm pump is recommended for stable flow rates during the sampling If the pump is so powerful to use at 1 or 2 liter min it is better to make a bypass for easier flow control It is recommended to use a mass flow controller to control the sampling flow rate Example A in Fig 4 2 If the mass flow controller cannot be used it is necessary to control the sampling rate by using a pinch cock or a flow meter with regulator before the pump as well as a gas volume meter Example C and D in Fig 4 2 Especially at the sites located in high altitude mountain the mass flow meters should be adopted to avoid the effect of the lower atmospheric pressure The mass flow meter should be installed between the filter holder and the pump Example B in Fig 4 2 A gas volume meter with the flow
217. the whole system from the sampling to the exhaust Such confirmation by the parallel measurement with the standard method is considered as the dynamic sensitivity check The dynamic sensitivity check should be performed by the installation administrator at the beginning of the monitoring in the monitoring station And it should also be carried out at the opportunity of the change of the sampling air system etc 1 Static sensitivity check The static sensitivity check is the method of checking whether an indicated value changes more than 4 compared with the predetermined value by installing the equivalent film used as the equivalent input material on the filter paper and measuring the change of the amount of the B ray attenuation Since the equivalent film is very thin film of 10 um or less handling must be prudent so that surface dirt or crack may not be attached Moreover if the filter paper is damaged at insertion or extraction of the film it would cause a filter paper crushing so careful cautions are required Some models have the function which the static sensitivity check is performed automatically and periodically and the results are recorded Although it is usually confirmed that a measured value of the equivalent film is within the fixed range when the span coefficient is changed the average value of the repetition measurement of the equivalent film should be used taking the probable error of the B ray radiation measurement into a
218. ther nitrogen oxides Nylon polyamide filters are preferred It has to be taken notice that the second polyamide filter collects partial sulfur dioxide hydrochloric acid and ammonia as along with nitric acid from the sampling air 3 Filters for sulfur dioxide and hydrochloric acid samplings The remaining sulfur dioxide and hydrochloric acid that pass through the second stage will be collected on the third stage The remaining sulfur dioxide and hydrochloric acid react with alkali substance on the filter mounted on the third stage For this purpose cellulose filters impregnated by potassium carbonate are preferred For the calculations of ambient concentrations the amounts of sulfur dioxide hydrochloric acid and ammonia collected by the second filter have to be added to those collected by the alkali impregnated filters 4 Filters for ammonia sampling The remaining ammonia that passes through the second and third stages will be collected on the fourth stage The remaining ammonia reacts with acid substance on the filter mounted on the stage The filters are preferable to be impregnated by phosphoric acid The cellulose filters which are same as the third stage filter could be utilized For the calculation of ambient concentration the amount of ammonia collected by the second filter has to be added to that collected by the acid impregnated filters The specifications of filters including as well as reaction and collected species for each fi
219. to this heterogeneous illumination of the grating the PDA leads to a higher residual noise compared to a uniform illumination To compensate this effect a quartz fiber mode mixer described is installed to the system Spectrograph The spectrograph used for this dissertation was a Czerny Turner type instrument e g TRIAX320 Jobin Yvon Spex Horiba Inc with a 320 mm focal length has three gratings that are interchangeable and PC controllable The grating was thermostated to 35 C The spectrograph slit width was set to 100 um yielding a spectral resolution of 0 3 nm FWHM Full Width at Half Maximum at an atomic emission line The light coming through entrance slit into the spectrograph was paralleled by the spherical mirror and reflected to a plane diffraction grating The dispersed light was then focused by a second convex spherical mirror onto the detector unit 66 Manual for Air Concentration Monitoring PDA detector unit A photodiode array PDA detector e g model S3904 Hamamatsu Photonics K K 2 5x25 4 mm dimensions 1024 pixels was used for the signal reading The PDA detector is usually cooled to 15 C with a Peltier cooler in order to reduce the effects of thermal noise The data produced by the PDA detector was recorded on a PC through a 16 bit analogue digital converter Incoming light excites a number of electrons proportional to the light intensity into the conducting layer of the semiconductor These mobile cha
220. tor power supply board the DC power supply board the lamp power supply board and the zero span status relay board The ozonator power supply board drives the ozonator lamp based on the setting of the ozone level A dial pot on the ozonator control panel or the level B potentiometer on the board It also typically houses circuitry to control the zero span solenoid and switches the analyzer in the sampling or the calibration mode The DC power supply board provides 24 V unregulated 15 V and 5 V regulated power for the operation of various electronics parts It also contains the driving circuitry necessary to energize the reference and sample solenoids The lamp power supply board drives the UV lamp in the optical bench It also includes the lamp 36 Manual for Air Concentration Monitoring block heating circuit to maintain the temperature at above 50 C The zero span status relay board allows the remote control of the internal ozonator via the 15 pins D type connector on the rear panel The zero and span status is output to acknowledge receipt of the remote control command signals Two selecting switches are located on the ozonator control panel One selector is used for selecting the sampling or calibration mode while the other is for activating the zero the ozone level A or B calibration check The microcomputer module houses the microprocessor board the memory board the counter board the peripheral interface PIA board the disp
221. tributions One is slowly varying in wavelength while the other shows rapid variations in 4 Platt 1994 The differential absorption T corresponds with the differential optical density o Rapid and slow variations of the absorption cross sections are in fact a function of both the observed wavelength interval and the width of the absorption bands that needs to be detected The NO radical shows relatively slow variations in 4 around 640 nm while the aromatics show very sharp bands in the UV at about 260 nm Both can be detected using the DOAS technique 260 280 300 320 340 1 2x10 1 0x10 1 oO x lt al oO 2 A am molecule 1 an molecule abs 2 o x x lt at 2 a 2 0x10 total absorption cross section o differential absorption cross section o 4 0x10 260 280 300 320 340 wavelength nm Figure 3 26 Absolute co versus differential o absorption cross section of ozone Note the different scales on the left hand o and on the right hand side 0 60 Manual for Air Concentration Monitoring In practice Gaps is smoothed or a polynomial is adapted to gain a spectrum which represents the part of ops slowly varying in wavelength In the next step Gabs is divided by this spectrum This leads to the differential absorption cross section o which represents only the part rapidly varying in wavelength Fig 3 26 shows the absolute and
222. ts in different conditions can be calculated by the following formula Yokohama City Research Institute of Environmental Science 2010 Since the coefficients were updated several times one must use the most updated coefficients when the coefficients are revised by relevant organizations aso2 39 4 293 273 T ano 4 746x 4781 3 7 474 2 PxRH ano2 1 050 10 x 44 6 7 206 4xPxRH anns 87 6 293 273 7 003 46 2 x 10 x 293 273 7 9 94xIn 6 53 where T average temperature during the measurement period C P 2XPy Pr Py Py water vapor pressure at 20 C 17 535 mmHg Py water vapor pressure at the average temperature mmHg 112 Manual for Air Concentration Monitoring References Acid Deposition Monitoring Network in East Asia 2003 Technical Document for Filter Pack Method in East Asia Network Center of EANET 20p Acid Deposition Monitoring Network in East Asia 2010 Technical Manual for Wet Deposition Monitoring in East Asia 2010 111p Aikawa M Hiraki T Tamaki M 2005 Characteristics in concentration of chemical species in ambient air based on three year monitoring by filter pack method Water Air and Soil Pollution 161 335 352 Aikawa M Hiraki T Tamaki M Kasahara M Kondo A Uno I Mukai H Shimizu A Murano K 2006 Filed survey of trans boundary air pollution with high time resolution at coastal sites on the sea of Japan during winter in Japan Environ
223. ture of 20 ml concentrated phosphoric acid and 70ml water Dilute with water to make a total of 100 ml Change amount according the number of samples lt For NEDA solution gt Dissolve 0 056 g N 1 Naphthyl ethylenediaminedihydrochloride into 10 ml water Store in a refrigerator Change amount according the number of samples lt For Color producing reagent gt Mix the Sulfanilamide solution and the NEDA solution in a 10 1 ratio 10 parts Sulfanilamide solution to 1 part NEDA solution lt For NO2 gt Pour 8 ml standard solution including blank solution into test tubes Add 2ml Color producing reagent and shake gently Store it for 30 minutes in refrigerator Send them to colorimetric analysis at a wavelength of 545 nm Wastewater should be treated lt For NOx gt Pour 8ml standard solution including blank solution into test tubes Add 4ml Diethyl ether to remove PTIO Do it two times Add 2ml Color producing reagent and shake gently Store it for 30 minutes in refrigerator Send them to colorimetric analysis at a wavelength of 545nm Wastewater should be treated Analytical method for NO2 by using spectrophotometer Return sample temperature to room temperature Add 2ml Color producing reagent and shake gently Store it for 30 minutes in refrigerator Send them to colorimetric analysis at a wavelength of 545 nm Wastewater should be treated Analytical method for NOx by using spectrophotometer Return sample temperature to room t
224. ular denuder which enables to avoid artifact of gas and particle interactions is also described Chapter 5 describes a guideline for preparation of standard operating procedures maintenance of air concentration monitors recording field conditions and instrument maintenance and safety management Chapter 6 describes a guideline for data reporting and validation This chapter covers specification of a monitoring site how to compile raw monitoring data how to validate monitoring data submission of finalized data and data storage for future analysis Chapter 7 describes QA QC Quality Control and Quality Assurance of air concentration monitoring This chapter covers overall procedures such as monitoring site field and laboratory operations data management and determination of accuracy and precision Furthermore DQOs Data Quality Objectives of Fundamental parameters QA QC implemented by NC and training programs are described Finally Chapter 8 introduces future issues to develop air concentration monitoring in EANET This chapter covers new monitoring methods of NO online aerosol composition monitoring intercomparison of different monitoring methods and so on Because air concentration monitoring is closely related to wet deposition monitoring some common conditions such as location of monitoring site data reporting procedure QA QC etc were cited from Technical Manual for Wet Deposition Monitoring in East Asia 2010 E
225. ulb consists of a quartz glass which is extremely resistant to pressure and temperature relatively high light intensity in the UV region can be attained The electrodes are made of tungsten with endowments depending on the lamp type The cathode has a spiky peak to focus the electron emission while in contrast to that the anode is made of massive material which is to 64 Manual for Air Concentration Monitoring absorb the kinetic energy of the incoming electrons Typical characteristic parameters of lamps for the LP DOAS are described in Table 3 2 Table 3 2 Characteristic parameters of the lamp used for the LP DOAS Parameter Specification Manufacturer Hamamatsu Japan Type L2273 Power consumption 150 W Arc length 2 0 mm Window material Fused silica Spectral distribution 185 2000 nm Voltage 18 V DC Current 8 5 0 5 A DC Typical life time 1800 hr The telescope The telescope a single transmitter and receiver unit of the LP DOAS is a coaxial Schumidt Cassegrain type with a 200 mm parabolic main mirror focal length of 800 mm Light from the Xe lamp installed on the back of the telescope is emitted through a hole at the center of the main mirror towards the ambient air see Fig 3 29 As can be seen in the Fig 3 29 three aluminum coated plane mirrors were mounted in the telescope One circle plane mirror with a hole in the center and one elliptic plane mirror were mounted on the optical axis of the telescope The th
226. usual 699 Mechanical problem 599 Contamination of the samples or the sampling system 881 Calibration of instrument 129 Manual for Air Concentration Monitoring 6 4 Submission of finalized data Data reporting forms may be used for the reporting site condition on site local scale regional scale monitoring condition sample history chemical analysis condition and measurement results air concentrations meteorological parameters and other necessary results flags and data completeness Staffs in the NC will have responsibility for ensuring that all data elements are properly entered into the appropriate databases Data should be submitted to the NC once every year The NC will provide the formatted data reporting form as a Microsoft Excel file All data should be input in the distributed data form The followings should be described on every data form name of country and site code of country and site name of NAM name of laboratory code of laboratory and name of PCL 6 4 1 Information about sites sampling shipping laboratory operation 1 Site condition Any change in the circumstances of the site should be reported every year even if the site selection criteria remain satisfied Name and code of each site should be given first The category of a site should be determined by consideration of the siting criteria No site is included in more than one class The area around the site should be especially described in terms
227. utomatic monitors a filter pack sampling instrument meteorological instruments etc Information of filter pack samples history shipping frequency packing procedure laboratory operation etc Chemical analysis condition by ion chromatography Control chart 2 Measurement and calculated results Name of country and site Code of country and site Name of NAM Name of responsible laboratory and PCL Code of laboratory Sample number Code consist of country code site code year month and number Start and end of the date and time of monitoring Date of chemical analysis for the filter pack samples and other manual samples Air concentration measured by automatic monitors SO2 NO NO2 NOx O3 PMio PM 5 Air concentration measured by the filter pack and other manual samples SO2 HNO HCl NH3 and Particle matter components Meteorological parameters Wind Speed Wind direction Temperature Relative humidity and Solar radiation Leaf Area Index Optional Notes and any other information All the measured data should be reported to the NC through the National Center following the protocols as shown below The units to be used for SO2 NO NO gt and O should be ppb and that for PMj9 and PM_ s should be g m For automatic instruments SO NO NO gt and O should be expressed one digit under decimal and PM should be expressed by integral numbers e g 15 3 ppb for SO2 and 52 g m for PM Data treatment p
228. w volume air sampler and the relationship between the setting value of the calibration air and the measured mass concentration should be grasped The calibration air is introduced into the measurement monitor for calibration and the monitor is adjusted to show correct indicated value In the dynamic calibration the linearity is also checked with the several points of mass concentration including zero and some other concentrations in the measurement range The indicated value of the calibration air is evaluated as the following After zero and span check the calibration air with the concentration of around 200 ug m is put into the monitor and the indicated values are recorded Then the percentage of the difference between the indicated value and the setting value of the calibration air to the full scale is calculated Scale calibration for Tapered Element Oscillating Microbalance TEOM method automatic monitor Dynamic sensitivity check Since the filter oscillation method theoretically has detected mass directly the dynamic sensitivity check is performed by the check of the filter or element oscillating coefficient calculated by the method shown in the equation 3 14 The variation of the calculated coefficient is required within 5 Ky Am 1f 1 fo 3 14 Ko Oscillating coefficient g sec Am Mass of the particles on the filter weighed with the electronic balance g Ji Frequency before the increase in mass Hz fo
229. wable range as the result of the check by the equivalent film it is needed to confirm the contribution of filter paper to the measurement error by setting the filter paper with a different lot 3 Cleaning of flow meter It is necessary to pay much attention to the dirt of a float and a tapered vessel inner wall of a flow meter of an equipment in which the flow meter is used to monitor the gas exhaust from a pump Since the inside of a flow meter becomes dirty easily it should be cleaned by alcohol neutral detergent etc periodically Because the dirt of the inner wall the jam of a small tube and the dirt of a float may cause the measurement error of the flow rate in the model equipped with a mass flow meter or the model using a constant differential pressure gauge valve the operator should pay much attention to those situations 4 Flow stabilizer and pump volume Since the B ray absorption method is a filtration method the air flow resistance of the filter paper might increase by the collected particles and the flow rate might decrease at a high concentration period Therefore the flow stabilizer is usually equipped to measure against the pressure increase in a certain range In addition there are three types of equipment having different function for the situation in which the pressure reaches the control limit marginal pressure a model will move the filter paper automatically and start measurement again a model will continue sampl
230. y identify the laboratory issues to be solved for example by using filters or chemicals from another batch and by inspection of the routines in the laboratory A blank value should be determined as the median of 3 analytical results of blank filters One median value is available as the blank value for the sample sets obtained for one month The Network Center prepares artificial filter pack samples and distribute to the EANET participant countries to conduct inter laboratory comparison survey once a year The results of this survey in respective laboratory can be also used for improvement of data quality 4 2 Annular denuder Compared with filter pack method denuder method can avoid artifact and measure particulate components and gases separately so the sampling by a diffusion denuder and subsequent chemical analysis by ion chromatography is also recommendable method 4 2 1 Introduction Two different denuder systems are available for sampling and determination of gaseous nitric acid and ammonia The first procedure uses simple cylindrical tubes and the second procedure uses so called annular denuders where the air is passed through the annular space between two concentric cylinders The annular denuder arrangement allows the air flow rate to be increased and makes the subsequent chemical analyzes somewhat less demanding It was reported that the precision estimates of simultaneous 97 Manual for Air Concentration Monitoring
231. y because of preventing breaking filters in the case of example A in Fig 4 3 Then the mounted filter holder should be capped by an exclusive cap Airtight protection covers need to be mounted at the both ends of the filter pack Each filter pack should be tagged with the site code in the laboratory before it is shipped to the site Care should be taken to avoid materials in the filter pack which may be a source of contamination or absorb sulfur dioxide or other air components Teflon polyethylene polypropylene PVC and polycarbonate are recommended materials Ordinary rubber and nylon contains sulfur and should be avoided After leak checking the mounted filter holder should be sealed into a polyethylene bag And an aluminum coated bag should be used to seal it up further The sealed mounted holder should be kept in a transportation box during shipping to a monitoring site It is recommended that a transportation box is kept low temperature about 10 C cooling by reusable coolant in order to avoid evaporation of the sampled substances during transportation Shipping interval of the filter packs from the laboratory to the site is weekly or biweekly and vice versa depending on the sampling interval One extra filter pack complete with filters should be added as a field blank i e one field blank every week This filter pack should be handled in every way as the ones to be exposed returned with the other filter packs from the batch dismounted a
232. y blanks are stored in the lab and periodically tested The field blanks are kept in their containers and accompany the samplers to the field and are returned after the filters are exposed and are analyzed along with the exposed samples The concentrations determined from the exposed filters are then corrected using the blanks The lower detection limit is commonly defined as 2 to 3 times of the standard deviation of the 3 blank values Thus procedures improvements which reduce the standard deviation of the blanks result in significant improvements in the lower detection limits of the samplers The repeatability of the results is quantified and checked by use of duplicate samples Blank filters will be analyzed at same time for each compound The samplers are very easy to manufacture They are also very cheap to manufacture and all components except the impregnated filter can be reused They have many other advantages as well for use in the field For example they are small light and require no electricity It should be emphasized that they provide time integrated concentrations with continuous time coverage with the averaging time determined by the period they are exposed to ambient air at daily weekly or monthly intervals They are obviously not well suited for monitoring temporal variations over short time intervals or for detection of individual peak values or when real time measurements are needed 4 3 2 Species specific information
233. y the ozone generator Each reaction cell also houses a small 4 mm orifice to limit the total ozone flow rate to around 120 180 cc min as indicated by the corresponding flow meter The dry air required by the ozone generator is provided by drawing ambient air into a particulate filter where particulates are trapped and then through a perma pure dryer where water vapor is removed The small 3 mm orifice creates the differential pressure across the wall of the semi permeable membrane inside the perma pure dryer for the continuous drying process The external sampling pump provides the driving force to draw in the sample air as 296 Manual for Air Concentration Monitoring well as the ambient air required for ozone generation The vacuum gauge at the outlets of the reaction cells should read 558 8 660 4 mmHg A charcoal scrubber is present to remove any ozone 03 and nitrogen dioxide NO 2 from the exhaust of the reaction cells 115V AC pe A Hem SCREW FOR TEMPERATURE ADJUSTMENT INLET aaan il i gt OUTLET Taco Ja mE CNY y TAG Se Holle S Fi KHA SIGN G2 i aA ca aes Te i 4r ay Ss ite hc 3 EJ H A MOLYBDENUM EA Xi Pi oi Ry CHIPS joa e BH e fea lel qt z GSA e amp mo Agena EL ahs Slcoure AY EXTERNAL SAA j HOUSING CVV g wy ced Ay 2 ORAP E wa ry A o rlii NG oS rss CL Ast meruoswra S ay MATERIAL SNS A i hag 3 SNE AN Seed ao CO

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