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QA/QC of Scottish Air Quality Data

QA/QC of Scottish Air Quality Data. Ken Stevenson. Project Overview. Aim : To have all of the air quality data collected in Scotland in one accessible website Duration: 3-year contract Key elements: Data from National Network and LA sites in Scotland All quality assured to same standard

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QA/QC of Scottish Air Quality Data

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  1. QA/QC of Scottish Air Quality Data Ken Stevenson

  2. Project Overview Aim : • To have all of the air quality data collected in Scotland in one accessible website Duration: • 3-year contract Key elements: • Data from National Network and LA sites in Scotland • All quality assured to same standard • Data available via open access website • Long-term trend analysis • Mapping of pollutants throughout Scotland • Newsletter and Annual Report • Annual Seminar

  3. QA/QC of Scottish sites • Current Situation – • Total 60 Sites on Scottish website (up from 44 in 2007) • 32 sites operated under this project • 15 AURN • 13 funded by LAs or Scottish Grant Scheme

  4. Additional sites to be added • 5 sites temporily closed for relocation or roadworks • Fife Cupar • Edinburgh Haymarket • Aberdeen Market St • N. Lanarkshire, Harthill • N Lanarkshire, Ellis Road • 4 sites still to join the database • East Lothian, Mussleburgh North High St – In progress • East Renfrewshire, Clarkston – In progress • Shetland Stanley Hill – telemetry issues • North Ayrshire, Irvine – New site recently installed This will bring the total to 69 sites on the Scottish Database.

  5. QA/QC • Daily collection of data from each site • Scaling of data from last calibration results • Daily checking of data • On-going data update as new information becomes available • Site audits • Collection and storage of all calibrations and service records etc • 6-monthly data ratification • “Quality Circle” data review • Update of ratified data to the website • Assistance to LAs where-ever possible

  6. Site Audits 2008/9

  7. 6-monthly site intercalibration and audit • AEA visits every site every 6-months to undertake the intercalibration and site audit • Check Analysers • Check Calibration Gases • Site Infrastructure • Local Operator 0401

  8. Problems found at 2008/9 audits • Cylinders:- 4 NO cylinders • 1 SO2 Cylinder • PM Analysers:- 2 Ko out by more than 2.5% (2.8 – 4.8%) • 5 Main flows out (12 – 20%) • 6 Leak test failed • 1 Aux flow out (26%) • Gas Analysers 1 CO analyser fail leak test

  9. Feedback from site visits

  10. Data Ratification

  11. Example of Data Summary Sheet

  12. Measuring PM PM10 “Equivalent Analysers” • Partisol (with emfab filters) • Beta (Met One) unheated, with correction factor • Beta (Opsis SM200) with correction factor • TEOM FDMS (not with C drier) • (TEOM with Volatile Correction Model)

  13. Partisol • Automated sampling device - size-selected particulate matter on filters for later analysis. • Unattended operation for up to two weeks between site visits. • Filters are equilibrated, at 20° C and 50% R.H., for 48 hours - before and again after sampling. • Filters are carefully weighed using precision microbalances. • Concentration is a function of air volume sampled and weight PM of material on filter.

  14. Scottish Government Partisol Monitoring Programme 2007 • PM10 and PM2.5 at 5 sites for 1 year • Data problems common to all UK Partisol measurements • High field blank due to moisture • Worst with Quartz filters – even though these are specified in EU PM10 standard • Data now corrected and reported • Data used for PM Mapping in Scotland • Changed to Emfab filters in AURN

  15. BAM (Beta Attenuation Monitor) • Size-selected particulate matter on filter tape • Analysed by attenuation of Beta rays from Carbon-14 source • Zero from clean filter compared to soiled filter • Algorithm to calculate mass from attenuation • Correction factor may be required for equivalence

  16. FDMS

  17. FDMS Operation Issues • Filter Changing • Possible long-term problems with FDMS C system • Use B or CB type drier

  18. PM10 Monitoring in the Scottish Database • 45 monitors in total • FDMS 12 • BAM 4 • TEOM 29

  19. Conclusions • QA/QC work is key to everything • Audits and Ratification are a major part of the project work • PM - Partisol issues resolved • FDMS and BAM Equivalent PM analysers being deployed • We strive to support and work closely with LAs – • respond to requests and enquiries • offer advice • feedback if we see problems with the data • chase for calibrations • The database is building rapidly 2006 – ~20 sites 2007 – 44 sites 2008 – 60 sites

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