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Ozone Data Corrections

Ozone Data Corrections. Salt River Pima Maricopa Indian Community Community Development Department Environmental Protection & Natural Resources Air Quality Program National Tribal Forum – May 13 - 15, 2014. SRPMIC is located in Scottsdale, AZ. SRPMIC Ozone Monitoring Sites.

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Ozone Data Corrections

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  1. OzoneDataCorrections Salt River Pima Maricopa Indian Community Community Development Department Environmental Protection & Natural Resources Air Quality Program National Tribal Forum – May 13 - 15, 2014

  2. SRPMIC is located in Scottsdale, AZ

  3. SRPMIC Ozone Monitoring Sites Red Mountain Site High School Site Senior Center Site Lehi Site

  4. Reason for correcting raw data • Ensures data is “actual data” when it is corrected to standard • Regulatory program associate with standards • One of two agencies in EPA R9 adjusts data from most recent calibration curve • Derived from QA Handbook Volume II • View it as Traceability of Standards • Standard is carried down to raw data

  5. Raw Data Traces Back to SRP

  6. 13. Correct the concentration measured by the DAS by applying the latest calibration equation as: Intercept value from Analyzer’s calibration curve Raw data value = Slope value from Analyzer’s calibration curve where: Cda = the corrected concentration from the DAS (ppm), Cd = the measured concentration from the DAS (ppm), a = the intercept of the DAS calibration curve, and b = the slope of the DAS calibration curve. Referenced to QA Handbook for Air Pollution Measurement Systems, Volume II, Ambient Air Quality Monitoring Program, EPA-454/B-08-003. Section 12.2 when the calibration curve is subsequently used to compute concentration measurements x = (y - a)/mwhere y represents the analyzer response reading, ais the intercept and mis the slope, Section 12.4 EPA suggests the ambient readings be calculated from the most recent multipoint calibration curve or from a fixed nominal or universal calibration curve, and Section 12.5 Data Reduction Using Calibration Information. • Calculate the percent difference between the actual ozone concentration (Ci) and the corrected DAS concentration (Cd) for the audit and span concentrations as: • Percent Difference = x 100% 15. Record all values on the "zero/span check and QC check" worksheet and the precision check control chart. Compare the percent difference with the quality control limits specified in the project Quality Assurance Plan. If the difference is outside of the limits, perform the necessary corrective action.

  7. Statements from QA Handbook Volume II • Calibration relationship are applied to analyzer responses to determine actual concentration • Ideally, all ambient measurements obtained from an analyzer should be calculated on the basis of the most recent multi-point calibration • The calibration slope and intercept used to calculate ambient measurements are updated only for major calibration • When this calibration relationship is subsequently used to compute concentration measurements (x) from analyzer response reading (y), the formula is transposed to form, x = (y – b)/m.

  8. It all starts with Transfer Standard’s certification Average Slope and Intercept AQP\AIR MONITORING\Data Records Management\Certification\Ozone\75056 TS\TS Slope Records

  9. Created slope & intercept from site monitor calibration Transfer Standard’s slope and intercept is integrated to calculate in the ozone Multi-Point Calibration Calibration relationships of slope & intercept are calculated to analyzer’s raw data to determine actual concentration Slope and intercept is created from site monitor Multi-Point Calibration

  10. Data Correction in E-DAS Network when applying calibration relationship to actual concentration units

  11. Process of correcting ambient data to actual data EPA data reports are truncated Example Ambient data is .0302 ppm (parts per million) Apply most recent analyzer calibration curve slope and intercept (1.001 and -0.0002) to calculate ambient data .0302 ppm and to determine the actual concentrations would be .0304 ppm (.0302 - -0.0002)/ 1.001 = .0304 ppm raw data – intercept slope

  12. Sample of QC Data corrected to actual

  13. Ozone Reporting Data to EPA Most Agency Data Report SRPMIC Data Report to EPA

  14. Purpose • Data is Corrected to Actual from Raw • Have confidence data is corrected to the next level • Data is fine tuned even though not much difference from raw data • Data is more defensible especially when it is certified • We maybe doing extra steps in adjusting data than other agencies but it is worth reporting actual data

  15. Air Quality/Monitoring Staff Stan Belone, Environmental Engineer Email: Stan.Belone@srpmic-nsn.gov Mangas Slinkey, Senior Environmental Specialist Email: Mangas.Slinkey@srpmic-nsn.gov Shimmy Smith, Environmental Specialist Email: Corwin.Smith@srpmic-nsn.gov Administration Chris Horan, Manager, Environmental Protection & Natural Resources

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