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Procedures for QA/QC on the air quality monitoring data

Procedures for QA/QC on the air quality monitoring data.  Libor Černikovský, Blanka Krejčí Czech Hydrometeorological Institute, CZ http://www.chmi.cz cernikov@chmi.cz , krejci@chmi.cz. Content. QA/QC definition objective plan Legislation Data quality objectives (DQO)

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Procedures for QA/QC on the air quality monitoring data

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  1. Procedures for QA/QCon the air quality monitoring data  Libor Černikovský, Blanka Krejčí Czech Hydrometeorological Institute, CZhttp://www.chmi.czcernikov@chmi.cz, krejci@chmi.cz

  2. Content • QA/QC • definition • objective • plan • Legislation • Data quality objectives (DQO) • Collecting and reporting data • Examples Procedures for AQ/QC on the air quality monitoring data

  3. Definition Quality assurance (QA): all planned and systematic actions necessary to provide adequate confidence that a product, process or service will satisfy given requirements for quality Quality control (QC): operational techniques and activities that are used to fulfil given requirements for quality ISO Publications, ISO 8402, Quality Management and quality assurance - Vocabulary, International Organization for Standardization,1994 In relation to air quality network operation: Quality assurance refers to the overall management of the process involved in obtaining the data, i.e. relates to the measurement process Quality control refers to the activities undertaken to check and optimise data accuracy and precision after collection, i.e. concerned primarily with outputs Procedures for AQ/QC on the air quality monitoring data

  4. Objective = usable data The measured data must allow an objective and quantitative assessment of AQ, whether it complies with relevant national and European standards, limit values, guidelines and other rules. All tools used for AQ data acquisition, processing and evaluation has to generate data which is acceptable by the national authority, European Commission and European Environmental Agency in terms ofquantity, quality and format in which is data stored, presented and transmitted. Procedures for AQ/QC on the air quality monitoring data

  5. QA/QC plan 1/3 A document that • shall specify all the QA/QC activities required to achieve the data quality objectives (DQOs) • should describe how the data is assessed for precision, accuracy, representativeness, completeness (combined data capture and time coverage) and comparability • mechanisms usedwhen corrective actions are necessary The QA/QC plan should assure that • the quality of the data is known • the total measuring uncertainty can be quantified and is available to users of the data Procedures for AQ/QC on the air quality monitoring data

  6. QA/QC plan 2/3 The QA/QC plan of the AQ monitoring network must explicitly define • the unambiguous responsibility and authority for each of the activities contributing to the data quality • co-ordination between them Key elements are • organizational rules • operational rules • appropriate staff Procedures for AQ/QC on the air quality monitoring data

  7. QA/QC plan 3/3 Measured data QA/QC has to be guaranteed by • methods of measurements • standard operating procedures (SOPs) • hardware and software tools • maintenance, calibration and emergency plans • appropriate staff in terms of quality and quantity • personnel training and education Network design, station siting and instrument selection are crucial before the monitoring launch! Correct sampling is crucial, as well as storage and transport of samples... Procedures for AQ/QC on the air quality monitoring data

  8. Legislation … QA/QC plan shall specify all the QA/QC activities required to achieve the data quality objectives (DQOs) The system for acquisition, processing, evaluation and reporting AQ data has to be in accordance with the EU legislation on AQ as well as with EU standards, regulations and existing guidelines, i.e. primarily with • New Air quality directive 2008/50/EC • AQ Framework Directive (FWD) • Daughter Directives (DD 1-4) • Exchange of Information Decision 97/101/EC • Commission Decision 2004/461/EC (annual reporting on ambient air quality assessment) Directive On ambient AQ and cleaner air for Europe (AQD) see http://ec.europa.eu/environment/air Procedures for AQ/QC on the air quality monitoring data

  9. New Air quality directive 2008/50/EC … includes the following key elements: • The merging of most of existing legislation into a single directive (except for the fourth daughter directive) with no change to existing air quality objectives* • New air quality objectives for PM2.5 (fine particles) including the limit value and exposure related objectives – exposure concentration obligation and exposure reduction target • The possibility to discount natural sources of pollution when assessing compliance against limit values • The possibility for time extensions of three years (PM10) or up to five years (NO2, benzene) for complying with limit values, based on conditions and the assessment by the European Commission. * Framework Directive 96/62/EC, 1-3 daughter Directives 1999/30/EC, 2000/69/EC, 2002/3/EC, and Decision on Exchange of Information 97/101/EC. Procedures for AQ/QC on the air quality monitoring data

  10. Data quality objectives (AQD, Annex 1) 1/4 Specify • uncertainty • minimum data capture • minimum time coverage for each pollutant covered by the Directive Apply to individual analysers and samplers at individual station Procedures for AQ/QC on the air quality monitoring data

  11. Data quality objectives (AQD, Annex 1) 2/4 Notes: • Member states may apply random measurements instead of continuous measurements for benzene, lead and particulate matter if they can demonstrate to the Commission that the uncertainty, including the uncertainty due to random sampling, meets the quality objective of 25 % and the time coverage is still larger than the minimum time coverage for indicative measurements. Random sampling must be evenly distributed over the year in order to avoid skewing of results. The uncertainty due to random sampling may be determined by the procedure laid down in ISO 11222 (2002) "Air Quality – Determination of the Uncertainty of the Time Average of Air Quality Measurements". If random measurements are used to assess the requirements of the PM10 limit value, the 90.4 percentile (to be lower than or equal to 50 µg/m³) should be evaluated instead of the number of exceedances, which is highly influenced by data coverage. • Distributed over the year to be representative of various conditions for climate and traffic. • One day's measurement a week at random, evenly distributed over the year, or 8 weeks evenly distributed over the year. • One measurement a week at random, evenly distributed over the year, or 8 weeks evenly distributed over the year. Procedures for AQ/QC on the air quality monitoring data

  12. Data quality objectives (AQD, Annex 1) 3/4 The uncertainty (expressed at a 95 % confidence level) of the assessment methods will be evaluated in accordance with the principles of the CEN Guide to the Expression of Uncertainty in Measurement (ENV 13005-1999), the methodology of ISO 5725:1994 and the guidance provided in the CEN report "Air Quality – Approach to Uncertainty Estimation for Ambient Air Reference Measurement Methods" (CR 14377:2002E)... The uncertainty for modelling ... The uncertainty for objective estimation is defined as the maximum deviation of the measured and calculated concentration levels, over the period considered, by the limit value (or target value in the case of ozone), without taking into account the timing of the events. The requirements for minimum data capture and time coverage do not include losses of data due to the regular calibration or the normal maintenance of the instrumentation. Procedures for AQ/QC on the air quality monitoring data

  13. Data quality objectives (AQD, Annex 1) 4/4 To ensure accuracy of measurements and compliance with the DQO the appropriate competent authorities and bodies ... shall ensure the following: • that all measurements ... are traceable; • that institutions operating networks and individual stations have an established QA/QC system which provides for regular maintenance to assure the accuracy of measuring devices; • that a QA/QC process is established for the process of data collection and reporting and that institutions appointed for this task actively participate in the related Community-wide quality assurance programmes; • that the national laboratories ... are taking part in Community-wide intercomparisons... are accredited according to EN/ISO 17025 ... or are in the process of accreditation. All reported data shall be deemed to be valid except data flagged as provisional, i.e. all faulty data, zero/span checks, calibrations etc. must be removed from the reported dataset. Procedures for AQ/QC on the air quality monitoring data

  14. AQD, Annex VIIOzone target values and long-term objectives The following criteria shall be used for checking validity when aggregating data and calculating statistical parameters: Procedures for AQ/QC on the air quality monitoring data

  15. AQD, Annex XILimit values for the protection of human health Without prejudice to Annex I, the following criteria shall be used for checking validity when aggregating data and calculating statistical parameters: (1) The requirement for the calculation of annual mean do not include losses of data due to the regular calibration or the normal maintenance of the instrumentation. Procedures for AQ/QC on the air quality monitoring data

  16. DQO - remarks 1/2 In order for the measurements to constitute a compliant overall assessment of AQ in the Member State also need to be met • requirements for the appropriate numbers of monitoring points in Zones and Agglomerations (Annex V and IX) • locations and macro and micro sitingof monitoring points (Annex III and VIII) • reference methods for assessment (Annex VI) • calculation of uncertainty: the CEN standards provide a specific methodology for calculation of the uncertainty of measurement for direct comparison with the Directive DQO. The CEN standard requires that this is calculated annually and DEG is likely to require that this is calculated individually from the QA/QC test data for each analyser and reported annually to the Commission along with the corresponding annual data set. Procedures for AQ/QC on the air quality monitoring data

  17. DQO - remarks 2/2 Standardisation (Annex VI, C.): • all the results for gaseous pollutants have to be expressed at the following conditions of temperature and pressure: 293 K and 101.3 kPa. • for particle bound components, data shall be reported at ambient conditions. Correct metadata (geographical co-ordinates, altitude, station’s classification,...) are important, too. Procedures for AQ/QC on the air quality monitoring data

  18. EU Data Exchange Group (DEG) Implementing Provisions(IP) for reporting under AQD are currently being developed by the DEG (current status: draft, under preparation). Subject: • to provide the (technical) requirements for the AQ information flow under AQD • to serve as the main basis for the Commission's preparation of the IP for reporting under AQD and any related guidance Main IP elements: • specification of the reported information • information flow requirements (deadlines/periodicity, reporting scheme etc.) • common data format and metadata description (all data-flows) • description of tools for checking the format, data and metadata consistency and integrity • description of tools for merging, aggregation and rendering of the data Procedures for AQ/QC on the air quality monitoring data

  19. EMEP QA/QC http://www.nilu.no/projects/ccc/qa • EMEP Manual for sampling and chemical analysis • Data Quality Objectives • Flagging data • Detection limits and precision • Results from laboratory intercomparison • Results from field intercomparison • Data quality reports Procedures for AQ/QC on the air quality monitoring data

  20. EMEP data quality objectives for the acidifying and eutrophying compounds • 10 % accuracy or better for oxidized sulphur and oxidized nitrogen in single analysis in the laboratory • 15 % accuracy or better for other components in the laboratory • 0.1 units for pH • 15-25 % uncertainty for the combined sampling and chemical analysis (components to be specified later) • 90 % data completeness of the daily values • the targets, with respect to precision and detection limit follow the DQO of the WMO/GAW precipitation programme (WMO, 2004) • the targets for the wet analysis of components extracted from air filters are the same as for precipitation. For SO2 the limit above for sulphate is valid for the medium volume method with impregnated filter. For NO2 determined as NO2- in solution the accuracy for the lowest concentrations is 0.01 mg N/l. for heavy metals • 90% completeness • 30% accuracy in annual average • accuracy in laboratory... Procedures for AQ/QC on the air quality monitoring data

  21. Collecting and reporting data Theory: all of the QA activities are undertaken correctly, in compliance with the relevant CEN standards and SOPs the measurements will fulfil the requirements of the EU Directives without further checking Practice: there is a need to QC the data by careful data management and checking, analyser / sampler faults must be identified and addressed quickly in order to fulfil the DQO for data capture Prior to submission of data to the data user, any suspect data must be identified and investigated; in addition there is the need to ensure that the data are reported correctly Procedures for AQ/QC on the air quality monitoring data

  22. QC scheme - data flow & feedback 1. Monitoring station 2. Measurement data centre a) Laboratory (manual meas.) b) Automatic measurements 3. Monitoring data centre 4. National data centre 5. European data centre The roles and responsibilities must be unambiguous as well as the feedback between persons / institutions. Procedures for AQ/QC on the air quality monitoring data

  23. QC - level 1: monitoring station The hardware and software tools on monitoring station must guarantee a correct data storage (results of measurements and also supported parameters such as temperature, pressure, sampled air volume etc.) and a transmission to the data centre The first (automatic) check of completeness of data has to be implemented on automatic station Software should use automatic data flags (valid data, faulty data due to incompleteness, zero / span checks, calibrations, maintenance,...)  provisional data Procedures for AQ/QC on the air quality monitoring data

  24. QC - level 2a: laboratory The hardware and software tools in laboratory as well as organisational rules must guarantee correct samples storage and analysis, results of analysis evaluation, inspection and storage. Evaluation of conditions and rules during: • sampling (temperature, air volume and flow continuity,...) • storage and transportation of samples (temperature,...) • laboratory analysis should be done, too  provisional data Procedures for AQ/QC on the air quality monitoring data

  25. QC - level 2b: automatic meas. data centre The hardware and software tools as well as organisational rules must guarantee: • assurance of the integrity of transmission of data from the station to data centre • correct data storage • storage and use all supported information from station (e.g. zero / span check and calibration records, information about (ir)regular analyzers inspection,...) • review of data completeness and refill non-complete data series • review of data correctnessfrom technical perspective: • identify and inspect out-of-range, negative, constant, extreme,above thresholds, rapidly changed and other suspicious data • reject invalid data • correct data (e.g. if shift of measured level is known) • flag the data provisional data All procedures must ensure that data capture is maximised, i.e. the data must be analysed frequently (ideally daily) so that measurements affected by instrument fault and other faults could be recognised quickly. Some of reviews have to work automatically to allow real-time data release. Procedures for AQ/QC on the air quality monitoring data

  26. QC - level 3: monitoring data centre The hardware and software tools as well as organisational rules must guarantee advanced review of data correctness, reliability and consistency: • identify and inspect negative, constant, extreme, above thresholds, rapidly changed and other suspicious data • consider data integrity • compare data series from different stations • compare data series from one station to inspect relationship between different pollutants • provisional data – daily • valid data - monthly, quarterly, yearly All procedures must ensure that data capture is maximised, i.e. the basic review must be done frequently (ideally daily) so that measurements affected by instrument fault and other faults would be recognised quickly. Procedures for AQ/QC on the air quality monitoring data

  27. QC - level 4 & 5: national and European data centre The hardware and software tools as well as organisational rules must guarantee advanced review of data correctness, reliability and consistency on national and European level: • identify and inspect negative, constant, extreme, above thresholds, rapidly changed and other suspicious data • consider data integrity • compare data series from different stations and regions • compare data series from one station to inspect relationship between different pollutants Frequency: • national level: monthly, quarterly, yearly • European level: yearly Procedures for AQ/QC on the air quality monitoring data

  28. Examples: suspicious data  invalid data Zero / span check Procedures for AQ/QC on the air quality monitoring data

  29. Examples: suspicious data  valid data CO peak on traffic station Procedures for AQ/QC on the air quality monitoring data

  30. Examples: suspicious data  valid data Emergency SO2 outflow from chemical factory (30min values) Procedures for AQ/QC on the air quality monitoring data

  31. Examples: suspicious data  valid data O3 peak, 7th March 2005 Procedures for AQ/QC on the air quality monitoring data

  32. Examples: suspicious data  valid data 24.3.2007 Dust above central Europe from eastern Ukraine Procedures for AQ/QC on the air quality monitoring data

  33. Examples: suspicious data  checks e.g. alien values Procedures for AQ/QC on the air quality monitoring data

  34. Examples: suspicious data  checks Simple outliers or outliers based on statistical methods Procedures for AQ/QC on the air quality monitoring data

  35. Examples: suspicious data  checks Cumulative concentrations Procedures for AQ/QC on the air quality monitoring data

  36. Examples: relationships • some pollutant levels will be expected to rise and fall together or against • diurnal peaks of NO are usually associated with traffic during rush hours • diurnal behaviour of O3 • ... Procedures for AQ/QC on the air quality monitoring data

  37. Examples: relationships NO2 [ppb] + NO [ppb] = NOX [ppb] Procedures for AQ/QC on the air quality monitoring data

  38. Examples: relationships NO vs. O3 Procedures for AQ/QC on the air quality monitoring data

  39. Examples: relationships Different ratio PM10 vs. PM2.5 Procedures for AQ/QC on the air quality monitoring data

  40. Examples: especial events • Special weather conditions (usefull meteorological data support) • Service intervention • Unusual day run … Procedures for AQ/QC on the air quality monitoring data

  41. Thank you for attention... http://ec.europa.eu/environment/air • The CAFE Programme/ implementation of the Thematic Strategy on Air Pollution • Ambient Air Quality • New Air Quality Proposal • Existing Air Quality Legislation • Implementation of existing AQ legislation • Meetings & Workshops - CIRCA website • EU Focus on Clean Air • Useful links • Feedback Procedures for AQ/QC on the air quality monitoring data

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