Monitoring for Round 2 Review and Assessment. Sean Christiansen 33 RD IAPSC Conference 4 December 2002

Transcription

1 Monitoring for Round 2 Review and Assessment Sean Christiansen 33 RD IAPSC Conference 4 December 2002

2 Focus of this session: Focus on: Problem areas associated with monitoring during 1 st Round of Review and Assessment Questions fielded by the Monitoring Helpdesk Quality Control

3 Primary sources of information LAQM.TG(02) Draft Annex 1 Pollutant Specific Chapters Monitoring section in The Updating and Screening section Detailed Assessment Section Monitoring Helpdesk Interpretation of guidance DEFRA funded Consultancy free to LA s Source of References Web Resources Site Operators Manual

4 Resources Funding: SCA in 2003/04. Local Government Finance settlement Human resources: Planning, Procurement, Routine Calibration / Diff Tube exposure, Data Checking & Validation & Analysis Time: Time allocation for people to do the job Updating / Screening April 2003 Detailed Assessment April 2004

5 Main QC Objectives Measurements accurate, precise Representative of ambient conditions Results comparable and traceable Measurements consistent over time High data capture, evenly distributed Suitable for model verification Will ensure. data fit for purpose

6 Need for Monitoring Continuous Monitors Detailed Assessments one often sufficient located at an area of elevated concentration another may be needed if characteristics of areas of exceedence very different Diffusion Tubes Updating and Screening & Detailed Assessments far cheaper than continuous monitoring, more sites can provide an indication of the spatial extent of exceedences Determine longer term concentrations

7 Selection of monitoring methods Continuous Monitors NO 2 chemiluminescence SO 2 uv fluorescence PM10 Gravimetric EN (Although TEOM, β gauge may be continued to be used) Diffusion Tubes NO 2 (SO 2 ) NO 2. use supplier (Lab) who participate in the national NO 2 diffusion tube survey Co-locate with continuous monitor

8 Site selection and establishment Locations where objectives values are likely to be breached Public Exposure over the relevant averaging period Provides optimum location for future Model verification Public safety Site visibility Security and vandalism Access to utilities Planning permission Local pollutant sources & sinks Always a trade off Talk to Planners

9 Site selection for model verification Traffic Related Monitoring (e.g. NO2, PM10) Representative of Public Exposure Well defined emissions Non-Traffic (e.g. SO2, fugitive PM10) Representative of Public Exposure Predicted point of max impact from modelling Not necessarily absolute worst case location choose location to optimise model verification Talk to Modellers

10 Length of monitoring campaigns Dependent on type of objective under threat of being breached: NO2 annual average 6 months ok SO2 15 min objective 12 months required Minimum 6 Months irrespective of pollutant of interest Summer / Winter period Application of a correction factor to estimate annual means from short term programmes studies have shown factors subject to considerable error.

11 Routine Site Operations Regular Site Visits Routine Calibrations Audits / Traceability checks Service and Maintenance Keep Records

12 Data Review and Validation Stage#1 Screening: ongoing front-end process Review all data Do it quickly Use listings and graphs Common sense & experience Don t rely on automatic systems

13 Data Scaling Data Review and Validation Stage#2 Correction of raw data based on routine calibrations Plot Calibration factors against a time axis to check for consistency / analyser problems

14 Data Review and Validation Stage#3 Critical Review A periodic review Final stage of data acceptance before use Many inputs Time of day/year Meteorology Site characteristics Levels of other pollutants Site and service records Observations at other sites Data anomalies Instrument performance history Audits Calibration/drift control charts

15 Example 1 Data Screening #1 500 PM 10 concentrations (mg m -3 TEOM), without any QC, from fugitive emissions from a quarry 250 PM 10 concentration (mg m -3 ) 0 Mar-99 Jun-99 Sep-99 Dec-99 Mar-00 Jun Time

16 Example 2 Data Screening #2 Status information for validation of TEOM PM10 data TEOM Status OK TEOM Status OK 340 TEOM Status Exceptions 290 ug/m TEOM PM10 hourly /08/00 18/08/00 19/08/00 20/08/00 21/08/00 22/08/00 23/08/00

17 Example 3 Scaling Analyser Drift/Zero Clipping CO Raw Units Baseline Drift Evidence of Zero Truncation

18 Example 4 Scaling Corrected Data CO Conc. Units (ppm) Data corrected via routine calibrations Some data lost / deleted due to zero Truncation

19 Example 5 Critical Review Diurnal Variation Provides a powerful tool for analysing monitoring problems

20 R & A Monitoring Appraisal Checklist Have locations been appropriate? Are results as expected from experience? Does the overall monitoring assessment appear sufficiently robust? Has continuous monitoring been undertaken? Is the monitoring period and data capture appropriate? Have diffusion tube data been validated against a continuous monitor? Have diffusion tube data been scaled? Are sufficient details of QC procedures provided?

21 Summary Ensure Fit for purpose monitoring Over the correct period Appropriate locations Public Exposure Model Verification Use for Model verification and define areas of exceedence Robust Monitoring to support Round 2 Review and Assessment Review Data Screen Scale Critically Review Take time to check / analyse data and present in a useful form