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Site Operators Manual - UK-Air

1. Figure 6 3 1 UK Zones and Agglomeration AEA A28 SITE OPERATORS MANUAL Table 6 3 1 Table showing the populations of the zones and agglomerations Easter East Midlands Central Scotland Scottish Borders 266 18 340 957 Northern Ireland Reading Wokingham Urban Area 305 78 277 47 260 47 265 23 Birkenhead Urban Area 266 36 CD 220 76 218 16 180 68 1 083 32 dinburgh Urban Area 432 41 ardiff Urban Area 264 39 191 71 elfast Metropolitan Urban Area 517 81 v ojm io AEAT ENV R2750 AEA A29 SITE OPERATORS MANUAL AEAT ENV R2750 6 3 Site Classification 6 3 1 Site Selection General Location From the description of the distribution of pollutant species in the urban environment Section 6 2 it can be concluded that the highest concentrations of NOz CO and SO are likely to be found in the central city areas close to busy roads However ozone levels will be depressed in such locations The original objective of the EUN was to monitor at sites with representative levels of pollution to which the public are generally exposed for significant periods of time It was not intended to monitor extreme levels for instance those found along the kerbside to which people are usually exposed for very short periods Within this philosophy urban network sites have generally been located in central city areas but at locations not unduly influenced by a single large so
2. Site Operators Manual Automatic Urban and Rural Network Defra and the Devolved Administrations Report No AEAT ENV R2750 March 2009 SITE OPERATOR S MANUAL AEAT ENV R2750 Title Customer Customer reference Confidentiality copyright and reproduction File reference Reference number Prepared by Reviewed by Approved by AEA AURN Site Operators Manual Defra and the Devolved Administrations AUN QA QC RMP 1883 UNRESTRICTED Copyright AEA Technology plc All rights reserved Enquiries about copyright and reproduction should be addressed to the Commercial Manager AEA Technology plc AEAT ENV ED45077 ED45077 Issue 1 AEA Building 551 11 Harwell International Business Centre Didcot Oxfordshire OX11 0QJ Telephone 0870 190 6583 Fax 0870 190 6608 AEA is a business name of AEA Technology plc AEA is certificated to I809001 and ISO14001 Name Steve Telling Signature Stewart Eaton Ken Stevenson Name Signature f e o ius Name Rachel Yardley Signature Date March 2009 SITE OPERATOR S MANUAL AEAT ENV R2750 Executive Summary This manual has been written for the Local Site Operator LSO to provide both a general introduction to the Automatic Urban and Rural Network and also a hands on guide detailing the standard operating procedures and practices used in the network The manual is divided into two parts Part A is descriptive and contains general background information
3. Lambert relation described in Section 7 2 1 These are usually gas filter correlation infra red absorption analysers They use a filter wheel to allow alternate measurement of total IR absorption and that due to interfering species in the absorption band selected see Fig D4 in Appendix D Alternatively some CO analysers use the similar Non Dispersive Infra Red NDIR system Here differences in IR absorption between ambient air and reference gas air with all CO removed cause a metallic membrane in the detector to move back and forth in accordance with the alternating gas flow and CO concentration Ambient air is sampled using a pump unit The analysers continually display current CO concentrations and depending on the make and model of analyser other parameters can be selected as necessary An external carbon monoxide in air calibration cylinder and internal air scrubber or laser air cylinder are used to provide daily automatic check calibrations 7 2 5 Particle Sampling with Fractioning Inlets The main emphasis in ambient particulate monitoring at present is to determine the concentration of particulate material in the repirable and thoracic size ranges since these have the greatest significance in relation to human health The current requirements of the UK Air Quality Strategy and the EU Directive are to measure the PM size fraction the thoracic fraction However there is also interest in measuring smaller particles PM the
4. Southampton CO NO2 O3 PM10 PM25 26 Centre SO2 66 Wirral Tranmere NO2 03 PM25 106 Newport NO2 PM10 PM25 27 Barnsley 12 SO2 67 Preston NO2 O3 PM25 107 Chepstow A48 NO2 PM10 AEAT ENV R2750 AEA A 2 SITE OPERATOR S MANUAL AEAT ENV R2750 London Liverpool Queen s 28 Bexley CO NO2 PM25 SO2 68 Southend on Sea_ NO2 O3 PM10 108 Drive Roadside NO2 Liverpool CO NO2 O3 PM10 PM25 Aberdeen Union 29 Speke SO2 69 Grangemouth NO2 PM10 PM25 SO2 109 Street Roadside NO2 Manchester Stanford le Hope 30PPiccadilly NO2 O3 PM25 70 Portsmouth NO2 03 PM10 PM25 110 Roadside NO2 PM10 SO2 Sheffield CO NO2 O3 PM10 PM25 31 Centre S02 71 Canterbury NO2 111 Carlisle Roadside NO2 PM10 Rochester Leeds Headingley 32 Stoke NO2 03 PM10 PM25 S02 72 Northampton NO2 03 PM10 SO2 112 Kerbside NO2 PM10 London N Coventry Memorial Newcastle Cradlewell 33 Kensington CO NO2 O3 PM10 SO2 73 Park NO2 03 PM25 113 Roadside NO2 Tower Hamlets 34 Roadside CO NO2 7TA Dumfries NO2 114 Chesterfield Roadside INO2 PM10 Oxford Centre 35 Roadside NO2 75 Bournemouth NO2 03 PM10 115 Chesterfield NO2 PM10 PM25 Camden Port Talbot Margam 36 Kerbside NO2 PM10 76 Weybourne 03 116 PM2 5 PM25 Haringey London Marylebone 37 Roadside NO2 PM10 77 Inverness NO2 PM10 117 Road PARTISOL PM10 PM25 London London London N Kensington 38Haringey NO2 O3 78 Westminster CO NO2 O3 PM10 SO2 118PARTISOL PM10 PM2
5. Unit 9 8 Data sheets for the supplied gases are given in Appendix C Replacement of on site gas cylinders It is the responsibility of the gas standards supplier to ensure delivery of calibrated gas cylinders for the fortnightly instrument calibration The delivery of these will be undertaken by the gas standards supplier or occasionally by an agent of the supplier The delivery will be carried out at a time convenient to the LSO it is intended that the delivery will be scheduled during a routine calibration visit AEA A45 SITE OPERATORS MANUAL AEAT ENV R2750 It will be necessary for the LSO to remove the gas regulator from the empty cylinder and replace it on the new cylinder when installed Although this is a simple procedure training will be provided by the QA QC unit where required Safety glasses should be worn when changing cylinders and regulators The procedure is as follows e Ensure cylinder valve is fully turned off e De pressurise the regulator by operating the purge valve on the system The regulator will not unscrew safely when still under pressure e Unscrew the regulator using the spanner supplied Note that BS4 and BS15 all CO cylinders are left hand threads i e are unscrewed anti clockwise Left handed fittings are distinguished by notches cut in the fitting nut e Connect the regulator to the new cylinder ensuring that the sealing washer is intact When tightening the regulator apply moderate force only
6. the second Daughter Directive7 2000 69 EC covering CO and benzene and the third Daughter Directive8 2002 3 EC covering ozone which came into force on 9th September 2003 These Daughter Directives contain limit values and also upper and lower assessment threshold values which define areas where monitoring is required To conform to the requirements of these Directives additional monitors for NO2 SO2 and particulate matter were added to the AURN in 2001 and further monitors for CO were added in 2002 Additional monitors for O3 and rural NOx have been installed to comply with the third Daughter Directive on ozone which had an implementation date of 9 September 2003 In addition to defining the extent of monitoring these Directives also have specific data quality and data capture requirements 2 2 The Air Quality Strategy The development of the UK Air Quality Strategy over the last decade has been one of the major Government initiatives in air pollution control and research The Expert Panel on Air Quality Standards examined all available evidence on health effects together with data on current air quality in the UK much of which was collected as part of the AURN and its predecessors to develop recommended air pollution standards for the UK These standards were formulated into objectives to be achieved by 2005 in the UK National Air Quality Strategy first published in 1997 This strategy and the objectives set relied heavily on air pollution
7. QC requests that they do so AEA A20 SITE OPERATORS MANUAL AEAT ENV R2750 5 Data Requirements The primary data objective of the AURN is to comply with the European Union s Air Quality Directive Directive 2008 50 EC This Directive sets out data quality objectives regarding the maximum uncertainty of measurements and the minimum data capture These have been presented in Table 5 2 Table 5 1 Measurement uncertainty objectives given in EU Air Quality Directives Uncertainty for Minimum Data Capture Parameter Continuous Measurement NO NO 15 90 SO 1596 9096 Particulate Matter 2596 9096 CO 1596 9096 O 15 90 The methodology for calculating uncertainties are given in the relevant CEN documents MCERTS is the Environment Agency s Monitoring Certification Scheme that tests analysers to see whether they meet the CEN standards Only those analysers that meet the CEN standards are shown to be equivalent to the reference method In compliance to the European Directive all new equipment entering the AURN from 11 June 2010 must be proven to be equivalent to the reference All existing analysers used in the AURN should be proven equivalent to the reference method by 11 June 2013 More information on the reference methods can be found in Section 7 5 1 Data Capture Data capture rates provide a good indicator of overall network performance and the temporal representativeness of the information ga
8. can be upto 15 m from the kerb in some cases Kerbside A site sampling within 1 metre of the kerb of a busy road An area where industrial sources make an important contribution to the total pollution burden possible from roads populated and industrial areas Remote A site in open country located in an isolated rural area experiencing regional background pollutant concentrations for much of the time Any special source orientated or location category covering monitoring undertaken in relation to specific emission sources such as power stations car parks airports or tunnels An open countryside location in an area of low population density distanced as far as 6 3 2 Site Selection Detailed Urban Location Once a suitable part of the city in which to monitor has been identified certain local factors need to be taken into account in selecting the precise location for the monitoring station The intention is to select a site that is broadly representative of the quality of the air experienced by people in that part of the city during their normal lives In other words the sampling site should not represent a special case It is recognised that it is very difficult to identify a representative site particularly when taking into account factors such as visual impact and planning permission However in order to ensure meaningful comparisons of data between different stations sites should be classified according to th
9. concentration data from all UK national monitoring networks but especially from the AURN The strategy was revised and updated in 2000 with air quality standards and objectives for eight key air pollutants to be achieved between 2003 and 2008 An Addendum to the Air Quality Strategy was issued on 6 February 2003 This introduced tighter objectives for particles benzene and carbon monoxide and a new objective for polycyclic aromatic hydrocarbons Further information can be found at http Awww defra gov uk environment airquality strategy addendum 2 3 Local Authority Review and Assessment The 1995 Environment Act put a requirement on Local Authorities to review and assess air quality in their area As a fundamental input to this process air pollution maps of the UK were provided for use by Local Authorities as part of their initial assessment These maps were based on measurement data from the AURN and emission data from the National Atmospheric Emissions Inventory In later stages of the assessment these maps were heavily supplemented by local measurements and modelling Council Directive 96 62 EC on Ambient Air Quality Assessment and Management OJ L296 55 21 11 1996 Council Directive 1999 30 EC relating to limit values for sulphur dioxide nitrogen dioxide oxides of nitrogen particulate matter and lead in ambient air OJ L163 41 29 6 1999 Directive 2000 69 EC of the European Parliament and of the Council relating to limit value
10. deposited on the filter The calibration of the BAM is performed by measuring the absorption of a blank filter tape and a calibration control membrane with known absorption co efficient The monitor can be set to operate for 74 to 24 hour cycles with intermediate averages if selected The sampler will automatically take a measurement and feed the tape on if the filter loading reaches a pre determined level When operated with a PM sampling head the monitor is set to operate at a flow rate of 16 7 l min Gravimetric Sampler Particulate matter is collected on a 47mm filter which is subsequently analysed to determine the mass content Filters are exposed for 24 hours midnight GMT to midnight GMT thus providing daily average concentration data The Partisol 2025 currently used in the AURN has been designed to meet regulatory monitoring requirements for PM PM and other particulate fractions in the US Europe and other countries An active volumetric flow control system maintains a constant volume flow rate at a level specified by the user 16 7 I min incorporating a mass flow controller and ambient temperature and pressure sensors This flow rate provides the requisite 1m hr volumetric flow for the sample head to maintain its size fraction separation The sampler uses standard 47 mm filter media enabling post exposure analysis of collected material AEA A39 SITE OPERATORS MANUAL AEAT ENV R2750 A filter storage and exc
11. do not over tighten e Close the regulator outlet valve small knob and gently open the cylinder valve the inlet pressure gauge should rise Turn the cylinder valve off and check the regulator fitting for leaks using Snoop leak detector if necessary e Purge the air from the regulator by allowing gas from the cylinder to flush out all air in the regulator and line through the purge valve repeat twice Air in the system may give false readings and cause the NO calibration gas to become unstable and e fthe system is on non continuous operation pressurise the regulator and close the cylinder valve The regulator should be left in this pressurised state to ensure there is no ingress of ambient air If the system is on continuous operation leave the cylinder valve open with the system under pressure Any problems encountered during this procedure should be reported to the gas standards supplier and CMCU The daily CO auto calibration cylinder and its regulator are the responsibility of the Management Unit in the case of direct funded stations and the local authority in the case of affiliated sites to whom any problems regarding these should be addressed An inventory of the cylinders used in the network is maintained by QA QC Unit and is available on the AURNHUB website see section 2 3 4 for address 9 9 Sampling System The following applies only to sites fitted with a sampling manifold To enable any analyser to correctly mo
12. especially where major road systems industrial areas or other large sources are located away from city centre areas 6 2 4 Sulphur Dioxide Sulphur Dioxide SO is formed by the oxidation of sulphur impurities in fuels during combustion processes The largest contribution to SO emissions is from power stations which accounted for 55 of the total emissions in 2005 Since 1970 there has been an overall reduction of more than 8996 in SO emissions This is due to a number of factors including the reduction of coal used as a domestic fuel the increased use of low sulphur fuels such as natural gas and the increasing numbers of nuclear power stations over the period Geographically SO concentrations in the UK are highest in urban areas where there is still significant use of coal for domestic heating such as mining regions in the north of England and in N Ireland Modelling studies have indicated that the highest SO concentrations in cities usually occur in the central areas 6 2 5 Carbon Monoxide Carbon monoxide in urban areas results almost entirely from vehicle emissions The emission rate for individual vehicles depends critically on vehicle speed being highest at very low speeds Since CO is a primary pollutant its ambient concentrations closely follow emissions In urban areas concentrations are therefore highest at the kerbside and decrease rapidly with increasing distance from the road Since traffic is by far the most importan
13. for ozone For the protection of vegetation in zones the minimum number of sampling points required per unit area depends upon the maximum concentrations detected in the zone The Directive introduced the need for monitoring PM25 as well as the need to continue the monitoring of PMi PM has been shown to be a non threshold pollutant therefore the new Directive has introduced an exposure reduction target for PM5s The target is a percentage reduction in the average exposure indicator by 2020 The average exposure indicator should be a three year running annual mean concentration averaged over all sampling points Because of the need for an average exposure indicator it has been necessary to introduce new PM2 5 analyser into the AURN With the introduction of The Directive it was deemed that the AURN had many more SO and CO analysers than it required for this reason many SO and CO analysers were turned off late 2007 early 2008 On the other hand it was also deemed that the AURN did not have enough NO analysers it required and for this reason it has started to incorporate more NO analyser either via affiliation of existing sites or the construction of new sites into the network 6 2 The Distribution of Pollutant Species in Urban Areas The five principal polluting species NO NO NO2 SO CO O3 and PM sub divided into PM and PM 5 have different sources and hence in some cases different spatial distributions 6 2 3 Oxides of Ni
14. give the total PM present The mass concentration base mass concentration reference mass concentration oscillation frequency filter loading flow rates temperature and other diagnostic information can be displayed on the controller s LCD screen In addition mass concentrations filter loading and other diagnostics are output to the data logger as analogue voltages or through the RS232 interface The mass concentrations are given at ambient temperature and pressure The local site operators are not required to calibrate the TEOM but must change the filter cartridge and the purge filter as detailed in Appendix A and the purge filter The auxiliary flow cartridge will be replaced once every six months as part of the service and maintenance procedure BAM Beta Attenuation Mass Monitor The mass density is measured using the technique of beta radiation attenuation A small beta Source is coupled to a sensitive detector which counts the beta particles As the mass of particles increases the beta count is reduced The relationship between the decrease in count and the particulate mass is computed according to a known relationship Beer Lambert equation shown in Section 7 2 1 The beta ray monitor consists of a paper band filter located between a source of beta rays and a radiation detector A pump draws ambient air through the filter and the reduction in intensity of beta radiation measured at the detector is proportional to the mass of particulate
15. on the objectives structure and management of the network as well as generic technical principles employed in site operation Part B of the manual contains operational instructions The coloured pages describe the site operating procedures which are carried out by the LSO whilst the white pages describe their responsibilities regarding non routine site operations and equipment breakdown As the operating procedures are equipment specific a set of instructions is provided for each analyser type These pages are therefore colour coded according to instrument manufacturer in order to distinguish the equipment to which they apply Should it be necessary to replace an analyser with one from a different manufacturer or should a new analyser be installed then QA QC Unit will provide appropriate instructions for any equipment approved for use in the AURN The Automatic Urban and Rural Network site operator s manual is a working document prepared by the QA QC Unit and subject to continual update as equipment or procedures change Numbered copies of the manual are issued to specific owners who are directly involved with the network A register of these owners is kept and all updates are sent directly to them The un numbered copies are not registered and no updates will be supplied They are therefore complete with amendments only up to the date shown on the front cover It should not be assumed that these represent the latest version of the manual
16. should be within 1 5 m of the kerb roadside sites For industrial sites Where specific sources are being targeted monitoring should be carried out at the point of maximum impact as determined by modelling In addition to the above there are a number of practical considerations to be taken into account gt It should be practical for power and telephone connections to be made gt The site should be accessible for a lorry to deliver the housing gt It should be reasonably easy for gas cylinders to be delivered close to the site and transferred to the housing without difficulty There should be easy access to the site at all times gt The site should be in an area where the risk of vandalism are minimal and gt Account will need to be taken of visual impact and opportunities to hide the housing using pre existing structures For compliance with the EU Directives the following micro scale siting requirements must also be complied with AEA A32 SITE OPERATORS MANUAL AEAT ENV R2750 EU Directive Micro scale siting The following guidelines should be met as far as practicable The flow around the inlet sampling probe shall be unrestricted free in an arc of at least 270 without any obstructions affecting the airflow in the vicinity of the sampler normally some metres away from buildings balconies trees and other obstacles and at least 0 5 m from the nearest building in the case of sampling points rep
17. sources upwind of the station The pollution level should not be dominated by a single source unless such a situation is typical for a larger urban area Those sampling points shall as a general rule be representative for several square kilometres d Where the objective is to assess rural background levels the sampling point shall not be influenced by agglomerations or industrial sites in its vicinity i e sites closer than five kilometres e Where contributions from industrial sources are to be assessed at least one sampling point shall be installed downwind of the source in the nearest residential area Where the background concentration is not known an additional sampling point shall be situated within the main wind direction f Sampling points shall where possible also be representative of similar locations not in their immediate vicinity g Account shall be taken of the need to locate sampling points on islands where it is necessary for the protection of human health 2 Protection of Vegetation and Natural Ecosystems Sampling points targeted at the protection of vegetation and natural ecosystems shall be sited more than 20 km away from agglomerations or more than 5 km away from other built up areas industrial installations or motorways or major roads with traffic counts of more than 50 000 vehicles per day which means that a sampling point must be sited in such a way that the air sampled is representative of air quality i
18. the UK relies on all of the national air quality monitoring networks to provide basic data on air pollutant concentrations Such data are necessary to establish priorities for policy action and to assess the effectiveness of action in reducing air pollution concentrations A 1 SITE OPERATOR S MANUAL AEA AEAT ENV R2750 A 1 SITE OPERATOR S MANUAL Table 1 1 Monitoring sites in the AURN February 2009 the numbering of the sites relates to the site map shown in Figure 1 1 CO NO2 O3 PM10 PM25 1 Sibton O3 41 Glasgow Centre SO2 81 St Osyth CO NO2 O3 CO NO2 O3 PM10 PM25 2 Harwell NO2 03 PM10 PM25 SO2 42 London Hillingdon NO2 O3 82 Hull Freetown SO2 3 Bottesford O3 43 Leamington Spa NO2 O3 PM10 PM25 SO2 83 Reading New Town NO2 O3 PM10 PM25 Edinburgh St CO NO2 O3 PM10 PM25 4 Bush Estate NO2 O3 44 London Teddington NO2 O3 PM25 84 Leonards SO2 5 Eskdalemuir NO2 O3 45 Thurrock NO2 03 PM10 SO2 85 Market Harborough CO NO2 O3 Great Dun 6 Fell O3 46 Nottingham Centre NO2 O3 PM25 SO2 86 London Harlington NO2 O3 PM10 PM25 T Aston Hill NO2 O3 47 Bath Roadside NO2 87 Scunthorpe Town NO2 PM10 SO2 Lullington 8Heath NO2 O3 SO2 48 Manchester South NO2 O3 88 Birmingham Tyburn NO2 O3 PM10 PM25 SO2 9Billingham NO2 49 Bury Roadside CO NO2 PM10 89 Wigan Centre NO2 O3 PM25 Glasgow City 10 Chambers NO2 50 Narberth NO2 03 PM10 SO2 90 B
19. will result in highly variable ozone concentrations over small spatial scales with concentrations at lowest where corresponding levels of other pollutants such as NO are highest In cities therefore ozone concentrations will tend to be lower in central areas and increase in the suburbs although the spatial variation will be complex and in open spaces in urban areas levels of ozone may approach those found in nearby rural areas 6 2 7 Particulate Matter Airborne particulate matter can be found in ambient air in the form of dust smoke or other aerosols Particles may be either directly emitted into the atmosphere primary particles or formed there by chemical reactions secondary particles Both particle size usually expressed in terms of its aerodynamic diameter and chemical composition are greatly influenced by its origin As well as contributing to poor visibility and soiling effects particulate matter also has well documented effects on human health PM the mass fraction of particles collected by a sampler with a 50 inlet cut off at aerodynamic diameter 10um is appropriate for monitoring studies which are mainly concerned with assessing health related effects Major man made sources in the urban atmosphere include vehicle emissions diesel industrial processes domestic coal burning power stations incinerators and construction activity Existing PM data show that daily average concentrations are highest in the winter months an
20. 5 Bristol Old 39 Market CO NO2 79 Cwmbran NO2 O3 119 Harwell PARTISOL PM25 Exeter 40 Roadside NO2 03 80Wrexham NO2 PM10 SO2 120 Sandy Roadside NO2 PM10 121 Saltash Roadside PM10 122 Charlton Mackrell NO2 03 AEA A 3 SITE OPERATORS MANUAL AEAT ENV R2750 1 4 History of the Network Research measurements of air pollution with automatic analysers commenced in the early 1970 s in the UK Later such measurements were required for regulatory purposes and the Statutory Urban Network SUN was established in 1987 to monitor for compliance with EC Directive limit values on air quality To compliment this network the Department commissioned the Enhanced Urban Network EUN in 1992 This network was established as a result of the 1990 White Paper on the Environment This Common Inheritance which committed the Government to a significant expansion in urban air quality monitoring in the UK In particular it also identified the need to improve public availability of air quality information Phase one of the EUN network implementation involved establishing 12 urban background monitoring stations measuring five pollutants CO NO SO O3 and PM o Phase two took place in 1993 with the addition of a further 12 urban background sites and 13 stations monitoring Volatile Organic Compounds VOCs In 1993 the Department also launched the Air Quality Monitoring Progress and Partnership initiative to promote integration of local authority sites into th
21. 6 SITE OPERATORS MANUAL AEAT ENV R2750 1 6 Network Management and Operation The operation of such a large and geographically dispersed network as the AURN is de centralised with many organisations involved in the day to day running of the network The current structure of the network is outlined in Figure 1 2 Currently the role of Central Management and Coordination Unit CMCUJ for the Automatic Urban and Rural Network is contracted to Bureau Veritas whilst the Environmental Research Group ERG of King s College London has been appointed as Management Unit for the London Air Quality Network LAQN AEA part of AEA Group undertake the role of Quality Assurance and Control Unit QA QC Unit for the AURN to provide an independent arbiter of network performance The responsibility for operating individual stations in the network has been assigned to local organisations such as local authority Environmental Health Officers with relevant experience in the field Calibration gases for the network are supplied by Air Liquide Ltd and are provided with a UKAS certificate of calibration by AEA UKAS Calibration Laboratory 0401 The various organisations participating in the network are given in Table 1 2 Contact names and telephone numbers for these organisations are given in Appendix E Because a variety of organisations are involved in operating and managing the network it is essential that consistent procedures are adopted and implement
22. 80 secs 180 secs 180 secs 180 secs As already mentioned in previous sections only analysers that are proven to be equivalent to the reference method are allowed in the AURN by 11 June 2003 7 1 2 Accreditation The QA QC Unit AEA holds UKAS United Kingdom Accreditation Service accreditation UKAS Calibration Laboratory No 0401 to ISO 17025 for the on site calibration of the gas analysers NO CO SO O used in the AURN for flow rate checks on particulate analysers PM and PM and for the determination of the spring constant k for the TEOM analyser 2 XQ The accredited procedures for analyser calibration include the following analyser checks Noise Linearity Response time Converter efficiency SO hydrocarbon interference and Uncertainty evaluation The QA QC Unit also holds UKAS accreditation for laboratory certification of NO NO CO and SO gas cylinders AEA A35 SITE OPERATORS MANUAL AEAT ENV R2750 The QA QC Unit provides 15017025 accredited calibration services to each ESU ozone photometer prior to the beginning of inter calibration exercises The ESU operator is present during the calibration to ensure that the ESU photometer is set up and adjusted correctly and that the operator fully understands the calibration procedure All accreditations are examined annually by UKAS The QA QC Unit AEA Group must demonstrate technical competence and traceability of measurements to recog
23. AQN Environmental Research Group Quality Assurance and Control Unit AEA QA QC Unit A Calibration Gas Standards Supplier Air Liquide UK Ltd Full lists of LSOs and ESUs are listed on the AURN HUB website These lists are updated on a regular basis see section 2 3 4 AEA A11 SITE OPERATORS MANUAL AEAT ENV R2750 2 5 Air Quality Communications Unit Though not formally part of the AURN the Air Quality Communications Unit has a vital role in disseminating the data to the public and media AURN monitoring data is uploaded every hour as provisional data to the UK Air Quality Information Archive website www airquality co uk and to TELETEXT page 156 and a freephone telephone information service 0800 556677 In addition they are distributed daily to the media via the air quality bulletin service When the data has been further checked and ratified they are re issued to the Air Quality Information Archive website as ratified data The daily data summaries and the hourly data provided to the web TELETEXT and the freephone telephone information service are primarily intended to inform the public of current air pollution conditions Health advice is also provided so that sensitive individuals can take appropriate action such as increased medication staying indoors or reducing physical activity This service also now fulfils the EU requirement for information to be provided to the public and for pollution alerts to be issued wh
24. An electronic version of this manual is also available on the world wide web http www aeat co uk netcen airqual reports Isoman Isoman html AEA iii SITE OPERATOR S MANUAL AEAT ENV R2750 Table of contents 1 Introduction The Automatic Urban and Rural Monitoring Network 1 1 1 History of the Network 4 1 2 Air Quality Directives 5 1 3 The Air Quality Strategy 5 1 4 Local Authority Review and Assessment 5 1 5 UK National Indicators of Sustainable Development 5 1 6 Network Management and Operation 7 1 7 A Air Quality Communications Unit 7 2 History of the Network 8 2 1 Air Quality Directives 9 2 2 The Air Quality Strategy 9 2 3 Local Authority Review and Assessment 9 2 4 Network Management and Operation 10 2 5 Air Quality Communications Unit 12 3 Overview of the Automatic Urban and Rural Network 13 3 1 Objectives of the Automatic Urban and Rural Network 13 3 2 Organisation of the Network Division of Responsibility 13 3 3 Advice and Support Services to Local Authorities 15 3 Structure and Scope Of The Operational Manual 17 4 Quality Assurance Control Objectives 19 5 Data Requirements 21 Minimum Data Capture 21 5 1 Data Capture 21 6 Network Design and Site Selection 23 6 1 Network Design Criteria 23 6 2 The Distribution of Pollutant Species in Urban Areas 23 6 3 Fulfilling the requirements of the EU Directives 25 6 3 Site Classification 30 7 Monitoring Instrumentation 34 7 1 Selection of Monitoring Equipment 34 7 8 Operator s Guide to A
25. C Unit 10 2 10 Utilisation of Calibration Data in Producing Scaled Pollution Data The two point calibration will quantify the analyser zero and span response As the analyser gives an output signal which is recorded and averaged by the data logger it is vital that zero and span factors are also taken as readings from the data logger where used and not solely by reading the instrument display The zero response V is the response in volts of the analyser when the pollutant species being measured is not present in the sample airstream The span response V is the response again in volts of the anlayser to an accurately known concentration c in ppb parts per billion 10 9 or ppm parts per million 10 for CO of the pollutant species Both the zero and span responses will be taken on the concentration range at which the instrument normally operates Instrument zero response and calibration factors are then calculated using this data as follows Instrument Zero response Vz Instrument span response Vs Instrument calibration factor F c Ve V7 Ambient pollution data are then calculated by applying these factors to logged voltage output signals as follows Pollutant concentration F Va V7 where Va is the recorded voltage signal from the analyser sampling ambient air Application of calibration data in this way assumes that the instrument response is linear over the whole concentration voltage range in use The li
26. ITE OPERATORS MANUAL AEAT ENV R2750 gt Network intercalibrations and gt Traceability chains for the network Part A of this manual provides general background information on the objectives structure and management of the network Part B covers routine and non routine site operations to be carried out by the Local Site Operator as well as a description of the procedures to be carried out by the Equipment Support Unit Quality assurance and control methodologies are not static QA QC is an ongoing process in which revised or more sophisticated methodologies may be introduced as circumstances change new needs arise or additional resources become available Corresponding operational manuals must therefore also be evolving documents This manual is therefore modular to allow for any updates of individual sections of the text Amendments will be issued as and when required on the web version of the manual at the following address http www aurnhub co uk Isoman html for passwords contact stephen bird aeat co uk Local Site Operators will be responsible for incorporating the new amendments into their copy of the manual AEA A18 SITE OPERATORS MANUAL AEAT ENV R2750 4 Quality Assurance Control Objectives Good data quality and high data capture rates are essential if the AURN is to achieve its objectives To ensure that data is sufficiently accurate reliable and comparable i e consistent data quality assurance control QA QC pr
27. Informing the public about air quality Providing information for local air quality review and assessments within the UK Air Quality Strategy gt Identifying long term trends of air pollution concentrations and Assessing the effectiveness of policies in controlling pollution The data may subsequently be used for a variety of other purposes but these will remain secondary to the prime objectives stated above 3 2 Organisation of the Network Division of Responsibility A brief outline of the principal responsibilities of the network participants is given in Table 3 1 below AEA A13 SITE OPERATORS MANUAL AEAT ENV R2750 ROLE ACTIVITIES CMCUs Central Management and Coordination Unit and Management Units Overall network management Site selection and installation Equipment procurement Appointment and management of local site operators Appointment and management of equipment support contractors Data acquisition from sites Front end data validation Provide provisional data to Communications Unit and QA AC unit QA QC Unit Quality Assurance and Control Unit Network intercalibrations Site operator audits Preparation and maintenance of operational manuals Local Site Operator training Final data ratification Investigation of poor data Commissioning of new sites Calibration of ESU photometers Gas Standards Supplier Provision of gas calibration standards and regulators LSOs
28. Local Site Operators Management of local site Assist with site installation Routine site calibration and maintenance Emergency call out visits ESUs Equipment Support Units Equipment supply and maintenance Emergency response to equipment breakdown Six monthly equipment servicing Maintain spare equipment and parts inventory Air Quality Communications Unit Receive hourly data from network managers Compile and disseminate air quality bulletins Table 3 1 Principal responsibilities of AURN participants AEA A14 SITE OPERATORS MANUAL AEAT ENV R2750 3 3 Advice and Support Services to Local Authorities This manual describes the operational procedures for the AURN and the monitoring sites within that network However it is recognised that these procedures may also be of interest to local authorities undertaking monitoring as part of the process of air quality review and assessment To provide specific support to local authority air quality monitoring for review and assessment DEFRA and the DA s have provided detailed technical guidance which can be found on http www defra gov uk environment airquality local guidance index htm along with an air quality monitoring helpline 0870 190 6050 3 3 1 Site Information Archive www bv aurnsiteinfo co uk The Site Information Archive is a website prepared by Bureau Veritas that provides information on each monitoring station within the UK Automatic Urban an
29. Wiring Regulations 16th Edition 1991 Separate electrical circuits are provided for Socket outlets Air conditioning unit Lighting and Spare Sufficient standard UK 13 amp power sockets are available for the equipment plus spares These are located so as to minimise accidental disturbance by site operators The housings have internal fluorescent lighting and an emergency lighting system AEA A44 SITE OPERATORS MANUAL AEAT ENV R2750 9 6 Air Conditioning Freestanding monitoring station housings should be fully air conditioned in order to maintain a stable operating temperature of approximately 20 25 C within the enclosure Typically analysers can operate within a temperature range 15 35 C however in order to ensure a stable instrument response it is important to reduce the operating temperature variation to a minimum It is also important that instrument calibrations are performed within a known consistent and stable temperature range A constant temperature must be maintained within the enclosure doors must whenever possible be kept closed The temperature control on the air conditioning unit should only need adjusting at the beginning of the summer and winter seasons The air conditioning unit must be able to maintain the internal temperature at 20 30 C with a 3 KW equipment load and an ambient temperature of up to 35 C 9 7 Cylinder Storage It is necessary to keep compressed gas cylinders at the site for the pur
30. aintained and utilised by local site operators in accordance with the directions specified in this manual During every calibration visit a two point calibration will be performed This involves determining the response of the analyser when the pollutant of interest has had the following e Removal from the sample airstream zero response and e Present at an accurately known concentration span response Data scaling factors are determined from these responses and are used to convert raw voltage data into concentration units as described in Section 10 4 The QA QC unit verifies the integrity of on site standards every 6 months during the intercalibration exercise These network intercalibrations employ an independent standard to determine zero and span response In order to quantify any drifts in on site calibration standards which may have occurred during the preceding 6 month period If standards are found to have undergone significant drifts these will be replaced 10 2 7 Production of Zero Air Two methods of zero air production are used in the AURN either directly from a cylinder of zero grade air or by catalytically removing pollutant species from a sample airstream For the second method the QA QC unit has developed a zero air generator which consists of the following components Compressor to produce air sample Water drain to remove liquid water Needle valve to regulate airflow Silica gel to remove water vapour H
31. akdown For sites that are owned by DEFRA it is up to the CMCUs to notify the ESUs for sites that are affiliated to the AURN it is up to the site operators usually Local Authorities to notify the ESUs of any breakdowns It is of utmost importance that the ESU attend call outs as soon as possible to minimise analyser downtime For DEFRA owned sites the ESUS are required to attend to the fault within 48 hours For affiliated sites it is hoped that the site operators will have a similar arrangement with their ESUs An example specification for the servicing and maintenance of air quality monitoring equipment for the Automatic Urban and Rural Networks can be found in the appendix AEA A22 SITE OPERATORS MANUAL AEAT ENV R2750 6 Network Design and Site Selection This chapter describes design criteria used for the Automatic Urban and Rural Network and the selection of monitoring site locations 6 1 Network Design Criteria The Primary role of the AURN is to fulfil the requirements of the European Union Air Quality Directive 2008 50 EC For gaseous pollutants The Directive sets out the required minimum number of sampling points for the protection of human health per agglomeration zone This is based on 2 factors gt The population of the agglomeration or zone and gt If maximum concentrations in the agglomeration zone exceed the upper assessment threshold this is not a factor for when calculating the minimum number of sampling points
32. areas to meet the requirements of the third Daughter Directives see section 1 2 The London Air Quality Network LAQN was formed in 1993 to co ordinate and improve air pollution monitoring in London The LAQN is facilitated by the Association of London Government on behalf of the thirty three London Boroughs and is operated and managed by the Environmental Research Group ERG at King s College London Each Borough funds monitoring in its own area The core LAQN activities are funded by ERG itself The Department for Environment Food and Rural Affairs Defra and the Devolved Administrations DAs funds ERG to operate the Marylebone Road site and to maintain eight currently of the LAQN sites as affiliate sites to the UK Automatic Urban and Rural Network AURN AEA A8 SITE OPERATORS MANUAL AEAT ENV R2750 2 1 Air Quality Directives There have been considerable changes in the European air quality legislation in the last few years and the AURN has been expanded and adapted to conform to these new requirements The Air Quality Framework Directive 1996 62 EC on ambient air quality assessment and management5 sets the framework for air quality assessment and management throughout Europe via a system of Daughter Directives giving specific requirements and limit values for a range of pollutant species Three Daughter Directives have now been issued the first Daughter Directive6 1999 30 EC covering SO2 NO2 NOx particulate matter and lead
33. ata acquisition system failure gt Power cut or other site disruption gt Telephone line breakdown gt Operator error gt Vandalism gt Air conditioning faults and gt Data rejection after failing QA QC criteria It may be noted that if properly designed and configured daily automatic analyser calibrations should not result in loss of hourly average data In well run networks the major failure mode will be analyser breakdown these instruments are complex and 100 reliability cannot reasonably be expected Although some data loss due to analyser failure is unavoidable short of deploying back up instruments most other failure rates can be minimised by implementing the following Efficient data telemetry enabling on site problems to be identified rapidly Backup data storage media on site gt Rapid service maintenance and repair Comprehensive and documented site operational protocols gt Regular application of these protocols Experienced site operators gt Proven site infrastructure and system backup and gt The deployment of proven analyser types Detailed analysis of network problems leading to loss of data is provided in the quarterly and annual data ratification reports produced by the QA QC Unit and available on the reports database on the Air Quality Archive www airquality co uk and on the AURNHUB see sections 2 3 2 and 2 3 4 The main reason for data loss in the network is analyser bre
34. brations will be carried out on a monthly basis except at roadside sites which are on a fortnightly basis e 6 monthly network intercalibrations These exercises performed by QA QC Unit ensure that measurements from all network stations are completely representative and intercomparable In some cases such as for ozone analysers the data are directly scaled according to the results obtained from the network intercalibration The intercalibrations will also act as an independent audit of the system performance at each monitoring site In this way any site specific problems which may have developed and remained undetected are fully quantified At sites in the AURN network intercalibrations are undertaken every 6 months This chapter of the site operational manual will describe automatic calibration systems and techniques as well as gas standards to be used by local site operators in their fortnightly site calibrations Check listed operational procedures for fortnightly instrument calibrations these are provided in Appendix A The intercalibration exercises performed by the QA QC unit are introduced in Chapter 13 but will not be described in detail in this manual 10 2 Daily Automatic IZS Check Systems and Standards Daily automatic analyser checks provide valuable information on the routine performance of analysers and any long term response drifts The checks consisting of two point zero and span checks are controlled automatically by th
35. but unstable excited states These excited states decay giving rise to the emission of secondary fluorescent radiation The fluorescent radiation is detected by a photomultiplier tube causing an output voltage proportional to SO concentration A permeable membrane kicker is used to remove interfering hydrocarbons before reaction These ultra violet fluorescence UVF analysers use a filtered UV source and PMT detection system The main components of the analyser are shown in Figure D2 Appendix D A UV detector is used to monitor the source radiation and compensate for fluctuations in UV energy Ambient air is drawn through the system via a pump unit The analysers continually display current SO concentrations and depending on the make and model of analyser other parameters can be selected as necessary Either external gas cylinders or an internal permeation oven and zero air scrubber are used to provide daily automatic check calibrations 7 2 4 IR Absorption Carbon Monoxide Analyser Carbon monoxide CO concentrations in the sample air are measured by the absorption of infra red IR radiation at 4 5 to 4 9 micrometers m 10 m wavelength A reference detection system is used to alternately measure absorption due to CO in the ambient air stream and absorption by interfering species An infra red detector and amplification system produce output voltages proportional to the CO concentration The concentration is derived from the Beer
36. d lowest in the summer During winter episode periods increases in PM levels usually occur in association with rises in other traffic related pollutants such as oxides of nitrogen During the summer the photochemical oxidation of sulphur dioxide and oxides of nitrogen to particulate sulphate and nitrate is another important source PM the mass fraction of particles collected by a sampler with a 50 inlet cut off at aerodynamic diameter 2 5um is of an increasing concern as it is believed that it penetrates deeper into the lungs than PM and is harder for the body to remove For this reason many more PM25 analysers have been incorporated into the AURN Another change in the network is the introduction of analysers that can measure both non volatile and volatile particulate matter 6 3 Fulfilling the requirements of the EU Directives For compliance with the EU Air Quality Directives the UK has been split into zones and agglomerations Figure 6 1 Agglomerations are continuous urban areas with a population of more than 250 000 there are 28 agglomerations in the UK The remainder of the country has been split into 15 zones These coincide with Government statistical regions in England and areas defined by the respective DA s in Wales Scotland and Northern Ireland AEA A25 SITE OPERATORS MANUAL AEAT ENV R2750 The European Union s Air Quality Directive 2008 50 EC set minimum requirements for air quality monitoring in each zone and agglo
37. d Rural Network including sites in the London Air Quality Network Information includes a description of the site the site address and the pollutants measured together with a location map and photos The site has recently been updated to provide site locations via a Google Earth platform 3 3 2 Air Quality Archive http www airquality co uk This web site has been prepared by AEA on behalf of DEFRA and the DAs to provided up to date comprehensive detailed information on air quality in the UK The site is also the national archive of air quality information and reports including detailed air quality monitoring data and statistics plus major sections on local air quality management and air quality research Each DA now has a dedicated web site which contains data for all AURN sites in their territory together with data from a selection of Local Authority sites http www scottishairquality co uk http www welshairquality co uk http www airqualityni co uk 3 3 3 Local Air Quality Management Web Site http www airquality co uk archive lagm laqm php Since 1997 local authorities in the UK have been carrying out a review and assessment of air quality in their area The aim of the review is to make sure that the national air quality objectives will be achieved If a local authority finds any places where the objectives are not likely to be achieved they must declare the area an Air Quality Management Area AQMA The LAQM web site hol
38. d to calibrate the analysers change sample inlet filters and perform analyser and site checks as fully described in Appendix A of this manual 7 4 Adaptive Kalman Filters Many of the gaseous pollutant analysers use adaptive Kalman filters This technology is used to detect rapid changes in pollutant concentrations The analyser changes its averaging time to constant in order to match the changes in the profile of the ambient sample This could affect the response characteristics of the analyser if the changes in pollutant concentration are not stable the effect of which could be a very smooth trace It is important that the adaptive filtering is set in accordance with the setting used in the tests carried out and the corresponding time constant is set to 30 seconds which is a reasonable compromise between quick response and low noise AEA A40 SITE OPERATORS MANUAL AEAT ENV R2750 8 Data Logging And Data Transmission Equipment Two methods of data logging are used in the AURN The analysers themselves either contain data logging capabilities or standalone loggers which may be PCs these are used to scan the outputs of the analysers and record data Both systems can be interrogated by the Management Unit data collection systems The logger scans the analyser output approximately every 10 seconds and stores them as 15 minute averages in the logger memory The data logger is programmed to trigger the daily analyser autocalibrations usi
39. ds information on the progress of each Local Authority in making the review and assessment It also gives information on any AQMAs declared and the status of any Action Plans AEA A15 SITE OPERATORS MANUAL AEAT ENV R2750 3 3 4 The AURN Project Information Hub http www aeat co uk com AURNHUB index html With the rapid growth in the use of the internet as a communication channel the QA QC Unit has developed the AURN project information Hub in order to assimilate store and share project information with all network participants The Hub is based on a branch diagram which links different topic areas within the project See Figure 2 1 It provides a wide variety of information in the form of documents and hyperlinks related mainly to the QA QC Unit s role in the AURN Information which is of particular relevance to the LSOs includes all network reports and the intercalibration and service schedules The Hub has been developed as a password protected Internet site for the network participants The password can be obtained from Stephen bird aeat co uk The website provides ready access to a wide range of AURN related information in a single convenient location This web site provides an effective new forum for promoting communication between the Network participants as well as being a particularly cost effective way of distributing and up dating network documentation e A Questions Site Information Archive n Site Lis
40. e data logger or analyser software and will not normally need any adjustment These checks usually take place around midnight The principles of operation of automatic zero and span IZS devices are given below AEA A49 SITE OPERATORS MANUAL AEAT ENV R2750 10 2 1 NOx Analyser Zero air is generated by passing ambient air through purafil and charcoal scrubbers before being passed into the reaction cell With time the quality of the zero air would eventually degrade as the scrubbers become exhausted These are therefore replaced at every six month service Some sites use a zero air cylinder which can give more consistent zero readings Span gas is generated by an NO permeation tube Zero air at a constant flow rate is passed across the tube which contains a quantity of pure liquid NO The tube is enclosed in an oven maintained at a constant temperature Provided the flow rate and temperature are kept constant the amount of NO which permeates from the tube into the air stream will be constant This gas thus produced then passes into the reaction cell to provide a span calibration response Alternatively on some newer analyser systems the NO calibration gas standard is also used for the autocalibration check Some systems operate daily whilst others may operate every two or three days 10 2 2 SO Analyser Zero air is generated by passing ambient air through a charcoal scrubber before entering the reaction cell Some sites
41. e national monitoring network where this met the national objectives In 1995 the Enhanced Urban Network and Statutory Urban Network were amalgamated to form the Automatic Urban Network AUN consisting at the time of 26 sites directly funded by the Department and 4 affiliated local authority sites Throughout the next five years over 50 local authority sites were subsequently integrated into the network including 14 of the London Air Quality Monitoring Network sites In 1998 the separate urban and rural networks were combined to form the joint Automatic Urban and Rural Network AURN consisting of 103 sites In order to ensure consistency throughout the network affiliated monitoring stations have all QA QC functions calibration gases data ratification operator training and data collection by the Management Unit funded by defra and the DAs All other costs associated with the monitoring station are the responsibility of the Local Authority Since 2001 further expansion of the network has taken place in order to comply with the requirements of the European Air Quality Directives During 2008 the network has again been expanded in site numbers extensive monitoring of PM2 5 has been included into the network to comply with the new Air Quality Directive published in 2008 Directive 2008 50 EC of The European Parliament and of The Council of 21 May 2008 on ambient air quality and cleaner air for Europe http eur lex europa eu LexUriServ Le
42. e or other polluting activities The 3 UK Devolved Administrations Scottish Government Welsh assembly Government and the Department of the Environment in Northern Ireland also now all operate their own air quality websites which also contain all of the AURN data for their respective areas http www scottishairquality co uk http www welshairquality co uk http www airqualityni co uk AEA AT SITE OPERATORS MANUAL AEAT ENV R2750 2 History of the Network Research measurements of air pollution with automatic analysers commenced in the early 1970 s in the UK Later such measurements were required for regulatory purposes and the Statutory Urban Network SUN was established in 1987 to monitor for compliance with EC Directive limit values on air quality To compliment this network the Department commissioned the Enhanced Urban Network EUN in 1992 This network was established as a result of the 1990 White Paper on the Environment This Common Inheritance which committed the Government to a significant expansion in urban air quality monitoring in the UK In particular it also identified the need to improve public availability of air quality information Phase one of the EUN network implementation involved establishing 12 urban background monitoring stations measuring five pollutants CO NOx SO O3 and PMmy Phase two took place in 1993 with the addition of a further 12 urban background sites and 13 stations monitoring Volatile O
43. e scheme given in Table 6 3 1 In addition in order to meet the overall requirements for urban centre or background sites the following criteria should be employed as far as possible The site should ideally be located where a significant number of people spend their time gt It should be in as open a setting as possible in relation to surrounding buildings gt Immediately above and should be open to the sky with no overhanging trees or buildings and AEA A31 SITE OPERATORS MANUAL AEAT ENV R2750 gt The sample intake should be no higher than 10 m above local ground level and ideally between 1 4 m and 4 m For Urban Centre or Background Sites There should be no major sources of pollution within 50 m e g a large multi storey car park There should be no medium sized sources within 20 m e g petrol stations ventilation outlets to catering establishments etc Cars vans lorries should not be expected to stop with their engines idling within 5 m of the sample inlet The site should not be within gt 30m ofa very busy road 230 000 vehicles day gt 20m ofa busy road 10 000 30 000 vehicles day and gt 10m ofany other road 10 000 vehicles day The surrounding area within say 100 m should not be expected to undergo major re development so as to avoid disruption and to allow long term trends to be followed For traffic related sites The site should be within 1 m of the kerb kerbside sites and The site
44. ed by all participants To ensure this operational methodologies and best practice are comprehensively documented by the QA QC Unit 1 7 A Air Quality Communications Unit Though not formally part of the AURN the Air Quality Communications Unit has a vital role in disseminating the data to the public and media AURN monitoring data are uploaded every hour as provisional data to the UK Air Quality Information Archive website www airquality co uk and to TELETEXT page 156 and a freephone telephone information service 0800 556677 In addition they are distributed daily to the media via the air quality bulletin service When the data have been further checked and ratified they are reissued to the Air Quality Information Archive website as ratified data The daily data summaries and the hourly data provided to the web TELETEXT and the freephone telephone information service are primarily intended to inform the public of current air pollution conditions Health advice is also provided so that sensitive individuals can take appropriate action such as increased medication staying indoors or reducing physical activity This service also now fulfils the EU requirement for information to be provided to the public and for pollution alerts to be issued when specified alert thresholds are exceeded over a 3 hour period During severe episodes the Government may also issue advice to the public on how to reduce pollutant emissions by restricting car us
45. en specified alert thresholds are exceeded over a 3 hour period During severe episodes the Government may also issue advice to the public on how to reduce pollutant emissions by restricting car use or other polluting activities AEA A12 SITE OPERATORS MANUAL AEAT ENV R2750 3 Overview of the Automatic Urban and Rural Network 3 14 Objectives of the Automatic Urban and Rural Network All important decisions in designing networks selecting sites and instrumentation types or defining appropriate calibration operational procedures must ultimately be influenced or determined by the overall monitoring objectives Before attempting to document site operational and management practice these objectives must be clearly defined Previous national scale air quality monitoring networks in the UK such as the Statutory Urban Network were established to determine compliance with statutory air quality criteria or to assess temporal spatial concentrations of pollutants in order to provide a sound basis for government policy development Originally the Enhanced Urban Network EUN was established with the primary objective of collection and rapid dissemination of air quality information to the public With the amalgamation of the EUN and the SUN as well as the integration of affiliated sites the AURN now covers a wider range of monitoring objectives including Checking if statutory air quality standards and targets are met eg EC Directives gt
46. f the cylinder becoming contaminated by the use of regulators which contain ambient air or other calibration gases These regulators must not therefore be removed from the cylinder under normal operating circumstances Instructions on how to open and close cylinder regulator supplies must be strictly adhered to if contamination of the cylinder contents is to be avoided see Appendix A The use of cylinders has health and safety implications Provision must be made to securely strap cylinders to prevent them from falling this is especially important as regulators are to be left connected To obtain the analyser calibration span points the following calibration gases will be used Nitrogen oxides Nitric oxide NO in nitrogen Sulphur dioxide Sulphur dioxide SO in air and Carbon monoxide Carbon monoxide CO in air A second span check is undertaken on the nitrogen oxides analyser using a nitrogen dioxide NOz in air mixture AEA A52 SITE OPERATORS MANUAL AEAT ENV R2750 For all analysers the span checks are undertaken on the analyser running range This ensures that errors do not manifest themselves in the data scaling factors as a result of inconsistencies in analyser range ratios As there is at present no reliable and proven system for performing simple on site two point calibrations on O and particulate analysers all calibrations which produce data scaling factors for these instruments will be carried out by the QA Q
47. g s College London has been appointed as Management Unit for the London Air Quality Network LAQN AEA undertake the role of Quality Assurance and Control Unit QA QC Unit for the AURN to provide an independent arbiter of network performance The responsibility for operating individual stations in the network has been assigned to local organisations such as local authority Environmental Health Officers with relevant experience in the field Calibration gases for the network are supplied by Air Liquide UK Ltd and are provided with a 18017025 certificate of calibration by AEA UKAS Calibration Laboratory 0401 The various organisations participating in the network are given in Table 2 1 Contact names and telephone numbers for these organisations are given in Appendix E Because a variety of organisations are involved in operating and managing the network it is essential that consistent procedures are adopted and implemented by all participants To ensure this operational methodologies and best practice are comprehensively documented by the QA QC Unit AEA A10 SITE OPERATORS MANUAL AEAT ENV R2750 Figure 2 1 Network Participants Structure of the Network European Commission Local Site ip Operator Central Independent Management Equipment Support Unit Table 2 1 Network Structure EE eee en 0 esd Central Management and Co Bureau Veritas ordination Unit CMCU for the AURN Management Unit MU for the L
48. ged Replacements are available from the gas standards supplier currently Air Liquide UK Ltd When changing cylinders operators should be aware of the different valve outlets currently in use in the network All CO cylinders have BS15 outlets left hand thread but the NO NO and SO cylinders may have BS14 Left hand threaded regulators can be identified by notches cut into the corners of the nut A 4 to 7 digit number may contain numbers and letters which is stamped into the cylinder just below the neck uniquely identifies the cylinders supplied by Air Liquide UK Ltd this number is also written on the white dispatch label which is attached to the cylinder Any reference to the cylinder in correspondence with the QA QC unit should include this number 9 4 Equipment Housing Some monitoring stations are installed in stand alone self contained cabinets with an in built air conditioning unit whilst others are sited in pre existing buildings Sites installed in pre existing buildings AEA A43 SITE OPERATORS MANUAL AEAT ENV R2750 Where the monitoring equipment is installed inside a pre existing building the LSO will need to make arrangements with relevant persons or organisations in order to ensure access to the site is available whenever necessary 9 5 Self contained Monitoring Sites Where a number of air quality monitoring analysers are to be housed in stand alone self contained cabinets the housing should be of adequa
49. hange system enables the instrument to collect daily samples for a period of up to 16 days before operator intervention is required The temperature of the collection filter is maintained to within 5 C of the outdoor ambient temperature Filters are conditioned in a temperature and humidity controlled environment for 48 hours before being weighed both pre and post exposure Care should be exercised when comparing PM concentrations made using these four techniques TEOM FDMS BAM Gravimetric Analysis has shown that measurements made using the TEOM are approximately 1 3 times greater than the gravimetric PM instruments One difference is that the TEOM sample filter is maintained 50 C to keep the filter dry while the other two techniques sample at ambient temperature The addition of the FDMS unit to the TEOM ensures that no correction factor is required 7 3 Operator s Guide to Analysers The on site analysers except for the PM analyser are usually housed in temperature controlled rack units which also contain the data logger and auto calibration system where installed Block diagrams showing the main components of the analysers are given in Figures D1 D4 Appendix D There may be slight operational differences between different analyser makes and models However the measurement methodology will be the same The manufacturer s operational manual for each analyser will also be available on site The local site operators are routinely require
50. high risk respirable size fraction Measurement of these size fractions is achieved by using the appropriate size fractioning inlet head or cyclone cut off on the particle analyser New PM analysers will be rolled out across the AURN Network from 2008 AEA A37 SITE OPERATORS MANUAL AEAT ENV R2750 7 2 6 Particulate Analysers Samplers used in the AURN TEOM Tapered Element Oscillating Microbalance The tapered element oscillating microbalance TEOM system determines particulate concentration by continuously weighing particles deposited on a filter The filter is attached to a hollow tapered element which vibrates at its natural frequency of oscillation As particles progressively collect on the filter the frequency f changes by an amount proportional to the mass deposited m m kf where ko is a constant determined during calibration of the TEOM analyser The flow rate of air through the system is controlled using thermal mass flow controllers and automatically measured to determine mass concentration The filter must be manually changed before the mass loading is at the maximum allowed by the system The TEOM analyser consists of a sample inlet head attached to the sensor unit a control unit containing the mass flow controllers and system software and a carbon vane pump The total flow of 16 67 litres per minute through the sampling head is divided using a flow splitter to give a main flow of 2 or 3 litres per minute l mi
51. ion as measured with a reference sampler The FDMS analyser consists of a sample inlet head attached to the FDMS unit which is connected to the sensor unit a control unit containing the mass flow controllers and system software and a carbon vane pump As with the TEOM the FDMS samples ambient air with a flow rate of 16 67 l min through the sampling head Again this flow is divided using a flow splitter to give a main flow of 3 I min through the FDMS and filter cartridge and an auxiliary flow of 13 67 min A lower flow rate of 2 I min for the main flow is not required when using the FDMS In order to measure both volatile and non volatile components of PM the FDMS uses a switching valve to switch between a base measurement and reference measurement every six minutes AEA A38 SITE OPERATORS MANUAL AEAT ENV R2750 During the base measurement the FDMS samples as a normal TEOM through the sensor unit filter and weighs the PM During the reference measurement the FDMS diverts the flow through a purge filter in order to remove all PM from the airstream and the filter is weighed again The total PM measured during the 12 minute cycle is Mass Concentration Base Concentration Reference Concentration During the reference measurement any volatiles collected on the sensor unit filter with evaporate giving a negative mass concentration This concentration is subtracted from the base measurement concentration to
52. mance and defined scope of application gt All calibrations must be traceable through an unbroken chain to international standards the SI system Measurements should be made within a documented quality system and Where possible measurements should be harmonised with those made by organisations both within and outside UK This operational manual describes the documented procedures and record keeping systems necessary to ensure that on site network operations comply with the overall QA QC programme objectives specified above and are also compatible with the requirements of the UK National Measurement System Documenting procedures is in itself insufficient to ensure good practice In order to ensure that on site operations are compatible with the requirements of the QA QC programme full training is given to the LSOs by the QA QC Unit AEA A19 SITE OPERATORS MANUAL AEAT ENV R2750 This training is intended to ensure that the site operators are fully conversant with the monitoring techniques involved and with the network procedures required to maintain a high standard of performance Further details of the LSO training programme are given in Chapter 14 Compliance with documented procedures is also closely monitored by the QA QC Unit during intercalibrations audits of site operators and on going data assessments It is a requirement that LSOs must make themselves available for an intercalibration visit if a member of the QA
53. meration and the AURN has been and optimised during 2007 08 to ensure that these monitoring requirements are fulfilled Note that as a result of these changes the concept of critical sites is no longer meaningful and has been discontinued The following macro scale siting requirements defined in the Air Quality Directives must also be complied with AEA A26 SITE OPERATORS MANUAL AEAT ENV R2750 1 Protection of Human Health mpling points directed at the protection of human health shall be sited in such a way as to e data on the following The areas within zones and agglomerations where the highest concentrations occur to which the population is likely to be directly or indirectly exposed for a period which is significant in relation to the averaging period of the limit value s and Levels in other areas within the zones and agglomerations which are representative of the exposure of the general population b Sampling points shall in general be sited in such a way as to avoid measuring very small micro environments in their immediate vicinity which means that a sampling point must be sited in such a way that the air sampled is representative of air quality for a street segment no less than 100 m length at traffic orientated sites and at least 250 m lt 250 m at industrial sites where feasible c Urban background locations shall be located so that their pollution level is influenced by the integrated contribution from all
54. monitoring stations 61 of these monitoring stations are directly funded by Defra and the Devolved Administrations and a further 64 affiliated sites are owned and operated by Local Authorities of which 8 sites comprise in the London Air Quality Network LAQN The AURN was formed by the amalgamation of the former Enhanced Urban Network EUN the Statutory Urban Network SUN the Rural Monitoring Network and the inclusion of the monitoring stations from the LAQN Further expansion of the network is planned for 2009 with the addition of several new sites The AURN was formed by the amalgamation of the former Enhanced Urban Network EUN the Statutory Urban Network SUN the Rural Monitoring Network and the inclusion of the monitoring stations from the LAQN and the network has grown and developed over many years The pollutants monitored in the network are oxides of nitrogen NOx sulphur dioxide SO2 ozone O3 carbon monoxide CO and particles PM10 and PM2 5 The pollutants monitored at the sites and their locations are shown in Figure 1 1 Urban and Rural sites Table 1 1 gives a list of all the current operational sites in the Network Further information regarding monitoring site locations and pollutants can be accessed via the World Wide Web at http www bv aurnsiteinfo co uk The AURN is primarily targeted at providing the necessary data for legal compliance with EU Air Quality Directives However air pollution policy development in
55. n through the filter cartridge and an auxiliary flow of 14 67 or 13 67 I min The lower sample flow rate of 2 l min is often selected to prolong filter lifetime although the higher flow rate setting provides superior analyser response noise characteristics and is therefore to be recommended where possible The mass concentration oscillation frequency filter loading flow rates temperature and other diagnostic information can be displayed on the controller s LCD screen In addition mass concentration and filter loading are output to the data logger as analogue voltages or through the RS232 interface The mass concentration is given at the reference conditions of 20 C and 1 atmosphere The local site operators are not required to calibrate the TEOM but must change the filter cartridge as detailed in Appendix A The auxiliary flow cartridge will be replaced once every six months as part of the service and maintenance procedure FDMS Filter Dynamic Measurement System The filter dynamic measurement system FDMS has been developed as a retrofit instrument to most existing TEOM analysers and therefore the above principle of measuring PM mass concentration can be used The FDMS unit will be fitted to all existing TEOM s within the AURN from 2008 When added to the TEOM the FDMS unit allows measurement of both non volatile and volatile components of particulate matter PM and closely correlates with the gravimetric PM mass concentrat
56. n a surrounding area of at least 1 000 km2 A Member State may provide for a sampling point to be sited at a lesser distance or to be representative of air quality in a less extended area taking account of geographical conditions or of the opportunities to protect particularly vulnerable areas Account shall be taken of the need to assess air quality on islands AEA A27 SITE OPERATORS MANUAL AEAT ENV R2750 UK Agglomerations red and Non Agglomeration Zones Glasgow Urban Area Edinburgh Urban Area North East E Scotland Central Scotland Scottish Borders Highland v Greater Manchester Urban Area Blackpool Urban Area Belfast f 7 North East SOPORAN MMC 2 ide Teeside Urban Area Urban Area iR 4 f Tyneside iS Humberside v West Yorkshire vu ied b a AN Urban Area amp Merseyside gL M 4 Kingston Upon Hull Sheffield Urban Area The Potteries ottingham Urban Area Midlands Northern Ireland Preston Urban Area Liverpool Urban Area Birkenhead Urban Area North Wales West Midlands Urban Area South Wale Swansea Urban Area Southend Cardiff Urban Area OA Urban Area Bristol Urban Area zd reater London Urban Area South West y Bournemouth Urban Area Brighton Worthing EK D Littlehampton West Midlands Leicester Urban Area Coventry Bedworth Southampton Urban Area Reading Wokingham Portsmouth Urban Area Urban Area
57. nalysers 40 7 4 Adaptive Kalman Filters 40 8 Data Logging And Data Transmission Equipment 41 8 1 Data Retrieval 41 9 Station Infrastructure 42 9 1 Site Safety 42 9 2 Electrical Safety 42 9 3 Storage and Handling of Compressed Gas Calibration Mixtures 43 9 4 Equipment Housing 43 AEA iv SITE OPERATOR S MANUAL AEAT ENV R2750 9 5 Self contained Monitoring Sites 44 9 6 Air Conditioning 45 9 7 Cylinder Storage 45 9 8 Data sheets for the supplied gases are given in Appendix C 45 9 9 Sampling System 46 9 10 Sample Inlet for Particulate Analyser 47 9 11 Telephone Lines 48 9 12 Auto Calibration Facilities 48 10 Calibration Systems Principles 49 10 1 Introduction 49 10 2 Daily Automatic IZS Check Systems and Standards 49 Please Note Part B QA QC Data Ratification and Intercalibration Report for the Automatic Urban and Rural Network July September 2008 is a separate document AEA V SITE OPERATOR S MANUAL Part A General Information AEA AEAT ENV R2750 SITE OPERATOR S MANUAL AEAT ENV R2750 1 AEA Introduction The Automatic Urban and Rural Monitoring Network The Automatic Urban and Rural Network AURN is operated on behalf of the Department for Environment Food and Rural Affairs defra the Welsh Assembly Government The Scottish Government and the Department of the Environment in Northern Ireland collectively referred to as the Devolved Administrations DA s As of February 2009 the AURN consists of 125
58. nearity of the instrument is checked at six monthly intervals by the QA QC Unit The data scaling procedures detailed above are used for pollutants for which reliable transfer standards exist In the case of ozone however the UV measurement technique is inherently more stable than the production of ozone concentrations in the ambient range The fortnightly calibration of ozone analysers does not therefore serve to produce data scaling factors Ambient NO NOy NO data is scaled from the calibration of the NO and NO channels of the NOy analyser using the NO in nitrogen transfer standard This will directly output NO and NO concentrations with the NO concentration being given by NO ppb NOy ppb NO ppb An NO in air calibration mixture will however be used as a cross check on the NO channel calibration and to ensure that the catalytic converter in the instrument efficiently reduces NO to NO AEA A53 SITE OPERATORS MANUAL AEAT ENV R2750 Conversion of concentrations to units of ug m or mg m at the stated temperature and pressure of 20 C and 101 3 kPa may subsequently be undertaken Details of the relevant conversion factors are given in Appendix Exact procedures for instrument calibration are detailed in Appendix A 10 2 11 Use of Calibration Data over Extended Time Periods Many air pollution analysers undergo some form of drift in sensitivity over time This may be due to ageing of components such as photo m
59. ned to ensure high data quality and network efficiency In order for a full quality system to be applied to the Automatic Urban and Rural Network it is important that all operations are harmonised and documented This manual addresses on site procedures in order to ensure uniform operation and maintenance of monitoring stations by different site operators and equipment support units Specific issues addressed in this site operations manual include Overall requirements for site performance Site selection criteria Station infrastructure Instrumentation Vv Vv V V WV Routine and non routine site operational procedures v Routine and non routine Equipment Support Unit procedures Site housekeeping and gt On site calibration procedures Although encompassing all important aspects of site operations this manual in isolation does not constitute a full quality system for the network this requires full documentation and standardisation of the performance of the entire measurement chain It should therefore be recognised that some aspects of network operation are not fully addressed here These include gt Evaluation and selection of equipment and infrastructure gt Data handling systems gt Data scaling checking and review gt Long term data ratification gt Data dissemination techniques gt Data bulletins and reports gt Primary gas calibration procedures gt Site auditing AEA A17 S
60. ng control signals which drive relays to initiate zero and span measurement cycles Status inputs to the logger from analysers are used to monitor instrumental performance and detect error conditions The logger or analyser is connected through an RS232 serial interface to an autodial auto answer modem operating at a data transmission rate of up to 9600 baud The modem is connected via the public telephone system to the Managements Unit s central computer which automatically collects the logged data In the past chart recorders were used to provide a secondary data backup however they are now unsupported 8 1 Data Retrieval The CMCU and use a commercially available data retrieval system to poll data from sites on an hourly basis AEA A41 SITE OPERATORS MANUAL AEAT ENV R2750 9 Station Infrastructure 9 1 Site Safety General Site Safety National safety regulations apply in particular the Management of Health and Safety at Work Regulations 1999 and the Health and Safety at Work etc Act 1974 The latter applies to all persons connected with the work done by the network regardless of their organisation The Act requires that all employees while at work shall Take reasonable care for the health and safety of himself and other persons who may be affected by his acts or omissions at work and As regards any duty or requirement imposed on his employer or any other person by or under any of the relevant stat
61. nised metrology standards in order for the accreditation to be maintained 7 2 Principle of Operation of Automatic Analysers used in the AURN 7 2 1 UV Absorption Ozone Analyser Ozone concentrations are calculated from the absorption of ultra violet UV light at 254 nanometres nm 10 m wavelength The sample passes through a cell tube of length I and the absorption is measured using a UV detector An ozone removing scrubber is used to provide a zero reference intensity The analyser alternately measures the absorption lo of the air path with no ozone present and the absorption of the ambient sample The concentration c is calculated using the Beer Lambert equation alc L he where a absorption co efficient at 254 nm These are ultra violet absorption analysers with a single reaction cell and pneumatic valving to switch between zero and ambient air paths see Fig D3 Appendix D Ambient air is sampled using a pump unit The analysers continually display current O3 concentrations and depending on the make and model of analyser other parameters can be selected as necessary An internal ozone generator and zero air scrubber are used to provide daily automatic check calibrations Chemiluminescent Oxides of Nitrogen Analyser Nitric oxide NO in the sample air stream reacts with ozone O3 in an evacuated chamber to produce activated nitrogen dioxide NO NO O NO O NO O hv where O oxygen and hv the energy
62. nitor pollutant concentrations in the ambient atmosphere it is essential that all elements of the atmosphere be transferred unchanged to the analysis cell of the instrument For this reason a manifold sampling system is used at most sites in the AURN The manifold is constructed from an inert material such as glass or teflon The sample probe extends vertically through the roof of the housing to a height of at least 0 5 m thereby giving 360 unrestricted airflow The location of the sample inlet is such that ambient sampling is not influenced by gas discharges from the instruments calibration systems or adjoining installations such as the air conditioning unit A simple rain hood is installed to prevent water from entering the manifold The sampling manifold system has the following design specifications e Constructed from inert material e Inlet protection against rain insects or large particulate matter e De mountable for cleaning AEA A46 SITE OPERATORS MANUAL AEAT ENV R2750 e Sample residence time of less than 5 seconds between the inlet to the manifold and the inlet to the analysers e Minimum total flow through the manifold of 20 litres minute e Pressure drop in the manifold system not exceeding 0 25 water and e Fitted with outlets for 1 4 PTFE tubing for connection to analysers An independent suction motor is connected to the manifold to draw in a large excess volume of ambient air from which each analyser samples
63. ocedures are applied throughout the network Good QA QC practice covers all aspects of network operation including systems design and site selection equipment evaluation site operation maintenance and calibration data review and ratification The successful implementation of each component of the QA QC scheme is essential for the success of the programme The fundamental aims of a quality assurance control programme are as follows The data obtained from measurement systems should be representative of ambient concentrations existing in each urban and rural area gt Measurements must be accurate precise and traceable gt Data must be comparable and reproducible Results from this geographically extended network must be internally consistent and comparable with international and other accepted standards gt Results must be consistent over time and gt In order for seasonally or annually averaged measurements to be meaningful an appropriate level of data capture is required throughout the year The National Measurement System NMS exists to provide a formal infrastructure for all measurements in the United Kingdom At its core there are primary standards held by the National Physical Laboratory together with appropriate absolute or traceable metrology standards maintained at other designated laboratories Essential requirements for conformity with the NMS are as follows Measurement methods used must be of known perfor
64. of radiation emitted Joules The intensity of the chemiluminescent radiation thereby produced is measured using a photomultiplier tube PMT or photodiode detector The detector output voltage is proportional to the NO concentration The ambient air sample is divided into two streams in one ambient NO2 is reduced to NO using a molybdenum catalyst before reaction The molybdenum converter should be at least 95 efficient at converting NO to NO Separate measurements are made of total oxides of nitrogen NO NO NO and NO The ambient NO concentration is calculated from the difference NO NO NO These analysers are equipped with either a single or a double reaction chamber and PMT system The main components of the analyser are shown in Figure D1 Appendix D A solenoid valve is used to alternatively switch between NO and NO NO NO2 measurement typically at 15 second intervals Ambient air is drawn through the system via a pump and permapure drier unit The analysers display current NO NO and NO concentrations and depending on the AEA A36 SITE OPERATORS MANUAL AEAT ENV R2750 make and model of analyser other parameters can be selected as necessary Either external gas cylinders or an internal permeation oven and zero air scrubber are used to provide daily automatic check calibrations 7 2 3 UV Fluorescence Sulphur Dioxide Analyser Ambient air is exposed to UV light which excites SO molecules in the sample to higher
65. on on current air quality which has assisted in the preparation of the strategy and provides the yardstick whereby compliance with the strategy can be assessed at a national level 1 4 Local Authority Review and Assessment The 1995 Environment Act put a requirement on Local Authorities to review and assess air quality in their area AURN data from individual sites are widely used by Local Authorities in this assessment In addition air pollution maps of the UK based on measurement data from the AURN and emission data from the National Atmospheric Emissions Inventory are provided for use by Local Authorities as part of their initial assessment Analysis of data from the AURN provides detailed information on trends for individual pollution species this helps to assess the effectiveness of air pollution control measures implemented Many of the QA QC measures developed with the AURN are highlighted in the Technical Guidance provided to Local Authorities to assist them in carrying out their own monitoring programmes 1 5 UK National Indicators of Sustainable Development To support the UK Government Sustainable Development Strategy there is a suite of 68 national sustainable development indicators One of these indicators relates to urban and rural air quality Number 61 Air Quality and Health Two parameters are assessed for this indicator a Annual levels of particles and ozone b days when air pollution is moderate or higher The Ai
66. opcalite to remove CO Purafil to remove NO Activated charcoal to remove O3 NO and SO and e A particulate filter on the system outlet to ensure that no particulate matter especially scrubber material is blown into the analysers A diagram of the zero air generator is given in Figure D5 Appendix D Using an active system where air is forced through the scrubbers as opposed to a passive system which has the following advantages e The system is far less susceptible to leaks due to the positive pressure caused by the compressor along the flow path e The differences between output pressure and atmospheric pressure i e over pressurisation in active and under pressurisation in passive systems can be better regulated and controlled in an active system At some of the network sites however a passive scrubber system may be used in which air is drawn through the scrubbers by the analyser AEA A51 SITE OPERATORS MANUAL AEAT ENV R2750 The consumable components in the zero air generator is changed routinely at six monthly intervals as part of the service This will only be done after comparison with transfer zero standard at the QA QC audit The zero transfer standard used by the QA QC Unit for these comparisons will previously have been compared to certified zero air cylinders It may however be necessary for the LSO to regenerate or replace the silica gel component at more frequent intervals see section A3 11 Appendi
67. pose of instrument calibration Depending on the number of analysers on site the cylinders will be some or all of the following e 0 45ppm nitric oxide NO in nitrogen for urban monitoring stations 0 2ppm nitric oxide NO in nitrogen for rural monitoring stations e 0 45ppm nitrogen dioxide NO in air for urban monitoring stations 0 2ppm nitrogen dioxide NO in air for rural monitoring stations e 0 15ppm sulphur dioxide SO in air for urban and rural monitoring stations and e 20ppm carbon monoxide CO in air for urban monitoring stations 1 5ppm carbon monoxide CO in air for rural monitoring stations If a CO analyser is present there will be a 40ppm approx CO cylinder for the daily auto calibration system This cylinder is supplied by the management unit in the case of direct funded stations and the local authority in the case of affiliated sites the calibration cylinders and their regulators listed above are supplied by the gas standards supplier The gas standards supplier will supply the largest practicable cylinder size for each site in most cases this will be L40 size i e 40 litre volume Due to lack of space however some sites will be supplied with L10 size cylinders All cylinders should be supported securely during storage and use and the cylinder storage area should be correctly labelled with the appropriate warning labels The provision of safe cylinder storage facilities is the responsibility of the Management
68. r Quality Strategy for England Scotland Wales and Northern Ireland July 2007 http www defra gov uk environment airquality strategy Local Air Quality Management Technical Guidance LAQM TG 09 February 2009 http www defra gov uk environment airquality local guidance index htm Sustainable Development National Indicators http www defra gov uk sustainable government progress national index htm AEA AS SITE OPERATORS MANUAL AEAT ENV R2750 The assessment is based on data from the AURN The latest available trend plots for these indicators are shown below using AURN data up to 2007 These will be updated in April 2009 when the ratified AURN dataset for 2008 is available a Annual levels of particles and ozone 1990 to 2007 Co e Rural ozone United Kingdom e 0 Urban background ozone E an Na 0 e d e aoa 4 taos a e Roadside PM eo danas o e o Micrograms per cubic metre N UJ A ul eo M o Iz Urban background PM I e 0 1990 1992 1994 1996 1998 2000 2002 2004 2006 1 Ozone index shows annual mean of the daily maximum 8 hour running mean 2 PM index shows annual average Source Defra AEA Energy and Environment b Days when air pollution is moderate or higher 1990 to 2007 70 United Kingdom 60 50 40 30 20 10 Average number of days per site 0 1990 1992 1994 1996 1998 2000 2002 2004 2006 Source Defra AEA Energy and Environment AEA A
69. re precise time resolved measurements necessitating the use of automatic analysers The selection of instruments for the AURN was based on specific and proven analytical techniques for the pollutants measured Table 7 1 Table 7 1 Operating Principles of Automatic Analysers used in the AURN Pollutant Measured Operating Principle Os UV Absorption NO NO Chemiluminescence SO UV Fluorescence CO IR Absorption TEOM Tapered Element Oscillating Microbalance FDMS Flow Dynamic PM4o PM 5 Measurement System BAM Beta Attenuation Monitor Gravimetric Sampler These techniques represent the current stat of the art for automated monitoring networks and with the exception of the automatic PM4j PM 5 analysers are the reference methods of measurement defined in the EU Directives 7 1 14 CEN The EU requirements for achieving appropriate data quality are stated by the European Committee for Standardisation CEN Comit Europ en de Normilisation These standards specify the detailed performance specifications for reference monitoring methods and include methodologies for sampling calibration and on going QA QC as part of network operation The instrument performance specification is incorporated into the Environment Agency s MCERTS Monitoring Certification Scheme and into other European product certification schemes such as TUV Technischer berwachungsverein Technical Monitoring Association in Germany T
70. resenting air quality at the building line In general the inlet sampling point shall be between 1 5 m the breathing zone and 4 m above the ground Higher positions up to 8 m may be necessary in some circumstances Higher siting may also be appropriate if the station is representative of a large area The inlet probe shall not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air The sampler s exhaust outlet shall be positioned so that re circulation of exhaust air to the sampler inlet is avoided For all pollutants traffic orientated sampling probes shall be at least 25 m from the edge of major junctions and no more than 10 m from the kerbside The following factors may also be taken into account Interfering sources Security Access Availability of electrical power and telephone communications Visibility of the site in relation to its surroundings Safety of the public and operators The desirability of co locating sampling points for different pollutants and Planning requirements AEA A33 SITE OPERATORS MANUAL AEAT ENV R2750 7 Monitoring Instrumentation 7 1 Selection of Monitoring Equipment The selection of appropriate instruments is essential to the success of any monitoring network in achieving its stated objectives The objectives of the Automatic Urban and Rural Network AURN requi
71. rganic Compounds VOCs In 1993 the Department also launched the Air Quality Monitoring Progress and Partnership initiative to promote integration of local authority sites into the national monitoring network where this met the national objectives In 1995 the Enhanced Urban Network and Statutory Urban Network were amalgamated to form the Automatic Urban Network AUN consisting at the time of 26 sites directly funded by the Department and 4 affiliated local authority sites Throughout the next five years over 50 local authority sites were subsequently integrated into the network including 14 of the London Air Quality Monitoring Network sites In 1998 the separate urban and rural networks were combined to form the joint Automatic Urban and Rural Network AURN consisting of 103 sites In order to ensure consistency throughout the network affiliated monitoring stations have all QA QC functions calibration gases data ratification operator training and data collection by the Management Unit funded by Defra and the DAs All other costs associated with the monitoring station are the responsibility of the Local Authority Since 2001 further expansion of the network has taken place in order to comply with the requirements of the European Air Quality Daughter Directives There has also been a programme to install PM2 5 analysers Future expansion of the network is planned for 2009 with the incor of ozone and NOx analysers in rural and suburban
72. righton Preston Park INO2 O3 PM25 11 Strath Vaich O3 51 Glasgow Kerbside NO2 PM10 91 Sunderland Silksworth NO2 O3 PM25 SO2 Stoke on Trent 12 Lough Navar O3 PM10 52 Centre NO2 O3 PM10 PM25 92 Lerwick O3 CO NO2 O3 PM10 PM25 13Yarner Wood NO2 O3 53 Salford Eccles S02 93 Blackpool Marton NO2 O3 PM10 Southwark 14 High Muffles NO2 O3 5AlRoadside NO2 94 Leominster NO2 O3 SO2 15 Glazebury NO2 O3 55 Derry NO2 03 PM10 PM25 SO2 95 Auchencorth Moss O3 PM10 PM25 CO NO2 O3 PM10 PM25 16 Ladybower NO2 O3 SO2 56 Walsall Willenhall NO2 96 Bristol St Paul s SO2 Sheffield 17 Tinsley NO2 57 Barnsley Gawber NO2 O3 SO2 97 Fort William NO2 O3 London CO NO2 O3 PM10 PM25 London Marylebone CO NO2 O3 PM10 PM25 18 Bloomsbury SO2 58 Road SO2 98 Swansea Roadside NO2 PM10 PM25 CO NO2 O3 PM10 PM25 Auchencorth Moss 19 Belfast Centre SO2 59 Plymouth Centre NO2 O3 PM10 99 PM10 PM25 PM10 PM25 Newcastle CO NO2 O3 PM10 PM25 CO NO2 O3 PM10 PM25 20 Centre SO2 60 Wicken Fen NO2 O3 SO2 100 Port Talbot Margam SO2 CO NO2 O3 PM10 PM25 21 Cardiff Centre SO2 61 Brighton Roadside NO2 101 Horley NO2 Middlesbroug CO NO2 O3 PM10 PM25 London Cromwell 22 n SO2 62 Road 2 CO NO2 SO2 102 Stewartby SO2 CO NO2 O3 PM10 PM25 Sandwell West 23 Leeds Centre SO2 63 Bromwich NO2 O3 SO2 103 York Bootham PM10 PM25 London Cambridge 24 Eltham NO2 O3 PM25 64 Roadside NO2 104 York Fishergate NO2 PM10 Leicester CO NO2 O3 PM10 PM25 25 Centre SO2 65 Aberdeen NO2 O3 PM10 105 Oxford St Ebbes NO2 PM10 PM25
73. rk For further information on site safety contact the relevant Management Unit CMCU or LAQN MU or Local Authority affiliated sites 9 2 Electrical Safety For the Defra and the Devolved Administration DA owned sites electrical safety inspections of all monitoring equipment is undertaken on a regular basis during site servicing The electrical supply to the hut is tested at least every 5 years At affiliated sites the individual site owners are responsible for making suitable arrangements for safe operation of electrical equipment and to comply with the law AEA A42 SITE OPERATORS MANUAL AEAT ENV R2750 9 3 Storage and Handling of Compressed Gas Calibration Mixtures The calibration gases should be stored and handled in the correct manner as recommended by the manufacturer Copies of the gas data sheets for each of the 4 gas mixtures which are commonly used in the AURN are given in Appendix C Note that not all sites will have all 4 gases Air Liquide UK Ltd kindly supplied these data sheets although cylinders of different manufacturers may be in use at some sites The cylinders should be stored in the housing or rack supplied and supported securely at all times Regulators should be left attached to cylinders between calibration visits but the cylinder valve must be turned off after the calibration is completed unless the gas cylinder is used for the overnight auto calibration checks in which case the cylinder must be left
74. s for benzene and carbon monoxide in ambient air OJ L313 12 13 12 2000 8 Directive 2002 3 EC of the European Parliament and of the Council relating to ozone in ambient air OJ L67 14 9 3 2002 AEA AQ SITE OPERATORS MANUAL AEAT ENV R2750 However the maps continued to provide the essential input of background concentrations to the modelling work undertaken by Local Authorities In order to assess the effectiveness of air pollution control measures implemented it is necessary to have consistent and reliable measurement data over many years For the principal inorganic compounds this data is provided by the AURN Analysis of data from the AURN provides detailed information on trends for individual pollution species In addition an overall indicator of the air pollution climate of the UK is calculated annually from AURN data and is one of the 15 UK Headline Indicators of Sustainable Development http www sustainable development gov uk indicators headline h10 htm 2 4 Network Management and Operation The operation of such a large and geographically dispersed network as the AURN is de centralised with many organisations involved in the day to day running of the network The current structure of the network is outlined in Figure 2 1 Currently the role of Central Management and Coordination Unit CMCUJ for the Automatic Urban and Rural Network is contracted to Bureau Veritas BV whilst the Environmental Research Group ERG of Kin
75. t mounted externally on the roof Because of the TEOM FDMS detection method it is important for the sensor unit to be mounted on a sturdy platform which is independent from other activities free from external vibration and where practicable isolated from mechanical noise Gravimetric samplers Partisol 2025 are self contained units located externally of the monitoring enclosure AEA A47 SITE OPERATORS MANUAL AEAT ENV R2750 9 11 Telephone Lines In general there are two telephone lines to the monitoring station One is for data telemetry and is connected directly into the site modem whilst the other has a normal handset At some sites an additional phone line may be installed for the Gravimetric PM Partisol sampler Modems The site modem is used for data communication between the remote central station and the site logger via the site telephone line The modem requires Mains power A connection to the site telephone wall socket A connection to the logger serial port and Correct programming The modem program is held in a battery backed store and should not require re entry except after a prolonged power cut 9 12 Auto Calibration Facilities The provision of a daily automatic calibration check on site analysers is an essential part of the overall monitoring quality assurance programme These performance checks enable rapid remote detection of system faults via the telemetry system and thereby minimise data loss
76. t source of CO its spatial distribution will follow that of traffic this will generally result in the highest levels being observed in the city centre 6 2 6 Ozone A background ozone concentration exists in the atmosphere due to mixing of ozone from the stratosphere and its generation in the troposphere The background concentration depends on latitude and time of year in the UK measurements show the annual average to be about 35 ppb Lower average ozone concentrations are observed in urban areas since this background ozone is depleted by deposition to surfaces and reaction with other pollutants primarily NO in the atmosphere AEA A24 SITE OPERATORS MANUAL AEAT ENV R2750 Ozone is not emitted directly into the atmosphere in any significant quantity and its presence in the lower atmosphere at concentrations exceeding the background results primarily from a complex series of reactions involving NOx and hydrocarbon precursors in the presence of sunlight The reactions producing ozone occur under appropriate meteorological conditions in the plume of such sources as it moves downwind ozone formation can occur over a timescale of a few hours to several days As a result ozone concentrations are de coupled temporally and spatially from precursor sources and ambient concentrations that are strongly dependent on meteorological conditions together with scavenging and deposition rates In urban areas chemical scavenging by NO emissions
77. t zero response and calibration factors Vz and F will have to be updated in the Management Units and QA QC Unit data processing system on a regular basis following each calibration For this reason calibration records must be e mailed to Management Units and QA QC Unit immediately after each on site manual calibration or faxed where paper records are still used AEA A54 SITE OPERATORS MANUAL AEAT ENV R2750 10 2 12 Calibration During High Pollution Episodes In order to prevent losing valuable pollution data it is important to avoid calibrating the analysers during high pollution episodes The following pre calibration checks must be performed to confirm if any episode is occurring e Examine the analyser front panel reading to see if the instantaneous concentrations are above or close to the trigger levels given for each pollutant in Table 10 1 The analyser front panel readings may not be accurate but give an indication appropriate for this purpose e fthe above criteria are met the CMCU must be informed before proceeding with the calibration Table 10 1 Episode Criteria Trigger Level exceeded for 1 hour AEA A55
78. te size typically 3 0 m x 2 0 m x 2 5 m high to accommodate the instrumentation specified in Section 7 3 Each housing is typically supplied with Internal electrical wiring and fittings Air conditioning Shelving racking Sample intake manifold Gas cylinder store and 2 telephone lines for connection to modem and telephone handset some sites The cabinet is typically constructed of steel of 1 5 mm thickness to afford security with the outer surface coated with glass fibre reinforced plastic GRP With the affiliation of a greater number of Local Authority sites smaller stand alone monitoring cabinets will be integrated into the AURN These compact monitoring cabinets CMC s are used at roadside locations where available space is an issue and usually only contain one or two analysers typically a NO analyser and FDMS Each housing is typically supplied with the following e nternal electrical wiring and fittings e Air conditioning e Gas cylinder rack and e GSM modem The following information refers primarily to the directly funded Defra and the DAs sites housed in self standing cabins Some local authority owned affiliated sites and those housed in existing buildings may differ slightly in some aspects of the infrastructure Electrical Systems A 240V 50Hz 60 amp electrical supply is provided to the housing All internal electrical wiring and fittings conform to the Regulations for Electrical Installations IEE
79. the excess air is vented out of the hut Typical specifications of the air sampling manifold are given in Table 9 1 Table 9 1 Typical specifications for air sampling manifold Length 2500 mm Internal Diameter 3 2 metres second Residence time 0 8 seconds 0 25 ins HO Blower speed 3030 rpm measured by QA QC unit Although condensation in the manifold is unlikely to be a problem in the ambient conditions prevailing in the UK a water trap has been included The manifold is not heated as this is usually only required in very high temperature humidity operating conditions Ambient gas analysers are individually connected to the sample manifold via 1 4 PTFE or equivalent tube The length of this tube is kept as short as possible and is usually between 1 2 metres A PTFE filter is held in a PTFE coated filter holder situated on the front panel of the instrument rack in order to protect each instrument from ingress of particulate matter Another filter is situated at the back of each instrument but this will only be changed at 6 monthly intervals by the instrument service technicians or QA QC Unit If however this is the only filter it will need to be changed by the LSO during routine maintenance calibration 9 10 Sample Inlet for Particulate Analyser A separate sample port approx 4 cm in diameter in the roof of the housing is used to feed a sampling tube from the internal TEOM FDMS BAM sensor unit to the PM inle
80. thered They should not be assessed in isolation however as there is a trade off in the operation of any network between data quality and capture Overly stringent quality requirements usually involve low capture rates while conversely capture rates can always be maximised by relaxing or removing data quality acceptance criteria An acceptable compromise is to seek data quality commensurate with the overall aims and objectives of the network and maximise data capture within the constraints thus set Only if acceptable data quality and high capture rates are achieved can the performance of a network then be regarded as fully satisfactory The current target data capture requirements for the automatic urban and rural network is 90 in line with the requirements of the EU Directives Data loss in any network can result from a number of factors The most important in practice are as follows gt Analyser breakdown Site servicing gt Site relocation up grading The percentages for uncertainty in the above table are given for individual measurements averaged over the period considered by the limit value or target value in the case of ozone For a 95 confidence interval The uncertainty for the fixed measurements shall be interpreted as being applicable in the region of the appropriate limit value or target value in the case of ozone AEA A21 SITE OPERATORS MANUAL AEAT ENV R2750 gt Failure or leak of gas sampling system D
81. through instrument malfunction The automatic calibration facility provides a zero and span check initiated by the data logger The data recorded during the calibration are flagged and readily scrutinised by the Management Unit for evidence of faults The daily calibration cycle is timed to minimise loss of ambient data Details of the methods and auto calibration standards used are given in Chapter 10 AEA A48 SITE OPERATORS MANUAL AEAT ENV R2750 10 Calibration Systems Principles 10 1 Introduction The production of meaningful data from the Automatic Urban and Rural Network necessitates the regular calibration of all analyser types using traceable transfer gas calibration standards To ensure optimum data quality and capture a three tier system of calibration and analyser test procedures is employed in the AURN The major components of this system are briefly described below e Daily automatic IZS checks These allow instrumental drifts to be examined and act as a daily check on instrument performance Results should not be used for data scaling unless calibration gas is used for IZS see section 10 2 e Fortnightly monthly manual calibrations These are performed by the local site operators and are used by Management Unit to scale raw pollution data in mV into meaningful concentration units Instrument drifts are fully quantified by calibrating analysers manually with documented and traceable calibration standards These cali
82. trogen Nitrogen dioxide NO2 is one of a number of important oxides of nitrogen present in the atmosphere Nitric oxide NO and nitrogen dioxide together termed NO are the most abundant man made oxides of nitrogen in urban areas these are formed in all high temperature combustion processes although NO predominates Nitric oxide is not generally considered to be harmful to health at the concentrations found in the ambient atmosphere AEA A23 SITE OPERATORS MANUAL AEAT ENV R2750 For the UK as a whole approximately 45 of all oxide of nitrogen emission originates from motor vehicles with most of the remainder arising from power stations and other industrial sources Since power station and industrial emissions are usually from elevated sources motor vehicles represent by far the largest source of low level NO emission and therefore make the largest contribution about 75 or more to long term ground level concentrations in urban areas Hence the highest NO levels in cities are generally observed at kerbside locations However since much of the NO is formed from primary emissions of NO by time dependent oxidation processes in the atmosphere the relative decline in NO concentration away from the kerbside is slower than for NO Modelling and monitoring studies eg with diffusion tube samplers have shown that in general NO concentrations are greatest in central urban areas However this cannot always be assumed to be the case
83. ts About the Network ar Crtical Sites a New Sites i Network Organisation B defra and Devolved Administrations i 3 netcen QA QC Unit Contacts ERU CMCU w EB Equipment Support Units 6 Local Site Operators i Cylinder Supply Contractor Air Quality Archive 3 General News n Network News QB Newsletter X News 3 Intercalibration Schedule Operations P ESU Service Schedule amp Local Site Operator s Manual x A BB Cylinder Inventory Gas Calibration Ell Accreditation Field Operations G48 Report List Reports Ratification Reports we D Intercalibration Reports Nn CMCU Quarterly Reports 4 Annual Site Operator s Meeting 2002 Figure 3 1 The AURN Project Information Hub 3 3 5 Annual LSO Meeting To promote effective communications with all network participants the Mangement Units organise an annual meeting for Local Site Operators and other relevant parties where matters pertaining to the operation of the Network are discussed AEA A16 SITE OPERATORS MANUAL AEAT ENV R2750 3 Structure and Scope Of The Operational Manual In any air quality monitoring network particularly one with devolved and de centralised functions it is vital that the responsibilities of all participants are known and documented This documentation describes specific operational and maintenance procedures which are desig
84. ultiplier tubes degradation of catalytic scrubbers eg ozone scrubbers or drifts in electronic components The possibility exists to routinely adjust instrument sensitivities to align the instrument with the on site transfer standard For the following reasons however such routine adjustments will not be undertaken in the AURN e Asall instruments in the network are to be checked on a fortnightly basis any drifts will be easily quantified by consideration of the calibration history of the instruments It is most important therefore that this calibration history is not destroyed e The transfer standards themselves may drift from their original value If this were the case and both the analyser and on site standard were drifting it would be impossible having altered the analyser response to produce a final validated data set Drifts in the on site standard will be quantified by QA QC Unit intercalibration techniques at 6 monthly intervals e Routine instrument adjustments may lead to unreliable data being produced as the instrument stabilises Stabilisation periods may take many hours from the time of the adjustment and with sites being calibrated adjusted fortnightly this could lead to an appreciable proportion of data being degraded in quality Calibration results therefore serve only to scale ambient data They will not be used to routinely adjust analyser response factors As the instruments will not be adjusted the instrumen
85. urce Such sites may usefully be termed urban background or urban centre Section 6 4 2 provides more specific criteria for these sites Pedestrianised areas are frequently found in city centres where large numbers of people often spend significant periods of time These are likely to meet this overall objective of the network and are clearly candidates for the siting of a monitoring station The expanded AURN network also now includes monitoring at other urban site types such as kerbside industrial and suburban as well as at rural sites In this way a more comprehensive picture of population exposure can be established Sites are classified according to their location The classification system used in the national networks is given in Table 6 3 2 The majority of urban AURN sites are currently urban centre and urban background AEA A30 SITE OPERATORS MANUAL AEAT ENV R2750 Table 6 3 2 Site Classification System used in the Automatic and Rural Network Urban Centre An urban location representative of typical population exposure in towns or city centres e g pedestrian precincts and shopping areas Urban Background An urban location distanced from sources and therefore broadly representative of city wide background conditions e g urban residential areas Seater entneautkiis ofa town orcty on the outskirts of a town or city Roadside A site sampling typically within 1 5 metres of the kerb of a busy road although distance
86. use a zero air cylinder which can give more consistent zero readings Span gas is produced in a similar way to the NO analyser except an SO permeation tube is used in the oven Alternatively on some newer analyser systems the SO calibration gas standard is also used for the auto calibration check 10 2 3 Ozone Analyser Zero air is produced by an internal zero scrubber inside the analyser before entering the reaction cell Span gas is produced by the action of UV light in an ozone generator on the same zero airstream to produce ozone 10 2 4 CO Analyser Zero air is generated by passing ambient air through a heated Palladium Alumina catalyst before entering the reaction cell Some sites use a zero air cylinder which can give more consistent zero readings Span gas is supplied from a dedicated CO cylinder attached to the IZS span inlet on the equipment rack 10 2 5 Particulate Analyser It is not possible to provide a system to carry out daily automatic calibrations on the particulate analyser AEA A50 SITE OPERATORS MANUAL AEAT ENV R2750 10 2 6 Transfer Standard Calibration Systems As fortnightly manual zero and span calibrations are to be used to scale data into meaningful engineering units it is most important that the calibration gases used are both stable and traceable to primary standards The gas standards supplier is responsible for supply and calibration of on site transfer standards These standards are m
87. utory provisions to co operate with him so far as is necessary to enable that duty or requirement to be performed or complied with Employers shall conduct their work In such a way as to ensure so far as is reasonably practicable that persons not in his employment who may be affected thereby are not thereby exposed to risks to their health or safety In addition as far as their own employees are concerned employers shall gt Provide and maintain plant and systems of work that are so far as is reasonably practicable safe and without risks to health gt Arrange for ensuring so far as is reasonably practicable safety and absence of risks to health in connection with the use handling storage and transport of articles and substances gt Provide such information instruction training and supervision as is necessary to ensure so far as is reasonably practicable the health and safety at work of his employees gt So far as is reasonably practicable as regards any place of work under the employer s control the maintenance of it in a condition that is safe and without risks to health and the provision and maintenance of means of access to and egress from it that are safe and without risks gt Provide and maintain a working environment for his employees that is so far as is reasonably practicable safe without risks to health and adequate as regards facilities and arrangements for their welfare at wo
88. with the valves open Cylinders should be closed off in the following order by following these steps 1 First of all close the regulator outlet valve do not over tighten 2 Close the main cylinder valve tightly and 3 Finally release the primary regulator valve This traps gas in the regulator thus ensuring a positive pressure and hence no ingress of ambient air Failure to properly shut off cylinders may result in the cylinder contents leaking away a cylinder will become empty in this way in a matter of hours At most sites replacement calibration cylinders are delivered by the gas manufacturer The cylinders will be delivered by arrangement during a scheduled calibration visit The LSO will be responsible for removing the empty cylinder and placing the replacement cylinder in the storage rack The LSO will be responsible for removing the regulator from the empty cylinder replacing the valve cap and cylinder cap and re fitting the regulator to the new cylinder Training in this procedure will be provided by QA QC unit staff on an individual basis Safety glasses should be used during this operation Leak detection fluid is used for testing the regulator connection following fitting Should bubbles be detected at the cylinder valve outlet the nut should be tightened until the leak is stopped Care should be taken to avoid over tightening fittings When the regulator is removed the sealing washer should be inspected and replaced if dama
89. x A 10 2 8 Silica Gel QA QC Unit has replaced all the previously used blue indicating silica gel cobalt chloride in the zero air canisters with an orange indicator as the blue material is considered to be harmful and must be treated as hazardous waste for disposal purposes As there is no difference in the performance of the two materials QA QC Unit strongly recommends for health safety and environmental reasons that everyone uses orange silica gel in the zero air scrubbers Any blue silica gel found in the zero air canisters will be left on site for the LSOs ESUs to dispose of A safety data sheet for orange indicating silica gel can be found in Appendix C 10 2 9 Production of Span Calibration Gases The gas standards supplier supplies gas cylinders containing calibration gas mixtures of NO NO SO and CO for calibration of the relevant analysers These cylinders are purchased from a supplier which has demonstrated compliance with all relevant quality control procedures in the preparation of gas mixtures The cylinders are calibrated prior to being installed on site at the gas standards suppliers gas calibration laboratory To ensure traceability of measurements in the AURN all calibration gas standards are required to be calibrated by an organisation accredited to the requirements of 15017025 by the United Kingdom Accreditation Service UKAS Each cylinder is supplied with its own regulator This will minimise the possibility o
90. xUriServ do uri OJ L 2008 152 0001 0044 EN PDF AEA A4 SITE OPERATORS MANUAL AEAT ENV R2750 1 2 Air Quality Directives There have been considerable changes in European air quality legislation in the last few years and the AURN has been expanded and adapted to conform to these new requirements The Air Quality Framework Directive 1996 62 EC on ambient air quality assessment and management set the framework for air quality assessment and management throughout Europe via a system of Daughter Directives giving specific requirements and limit values for a range of pollutant species Four Daughter Directives were issued However with the exception of the fourth Daughter Directive covering PAH and Benzene the 1996 Framework Directive and the first 3 Daughter Directives have been superseded by the new 2008 50 EC Air Quality Directive 1 3 The Air Quality Strategy In addition to the requirements of the EU the UK has also adopted an Air Quality Strategy for the UK as part of the requirements of The Environment Act 1995 The first Air Quality Strategy was published in 1997 and was updated in 2000 an addendum was produced in 2003 and a fully revised Strategy was published in July 2007 The Air Quality Strategy sets National Air Quality Objectives and proposes measures to be considered for achieving these where they are not already met in order to achieve clean air for a good quality of life Once again the AURN provides informati
91. ypical performance specifications of analysers used in the AURN are given in Table 7 2 and have been taken from the following British Standards documents e Ambient air quality Standard method for the measurement of the concentration of nitrogen dioxide and nitrogen monoxide by chemiluminescence BS EN 14211 2005 e Ambient air quality Standard method for the measurement of the concentration of sulphur dioxide by ultraviolet fluorescence BS EN 14212 2005 e Ambient air quality Standard method for the measurement of the concentration of ozone by ultraviolet photometry BS EN 14625 2005 AEA A34 SITE OPERATORS MANUAL AEAT ENV R2750 Ambient air quality Standard method for the measurement of the concentration of carbon monoxide by non dispersive infra red spectroscopy BS EN 14626 2005 Air quality Determination of the PM o fraction of suspended particulate matter Reference method and field test procedure to demonstrate reference equivalence of measurement methods BS EN 12341 1999 and Standard gravimetric measurement method for the determination of PM25 mass fraction of suspended matter BS EN 14907 2005 Table 7 2 Typical Specifications for AURN Standard Gaseous Pollutant Analysers Repeatability Zero 2 gm 2 5 gm 2 gm 1 2 mg m At Limit Value 6 gm 8 gm 6 gm 35mgm Linearity 4 4 4 5 Period of Unattended Operation 3 months 3months 3 months 3 months 95 Response Time max 1

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