Ozone Data Validation & Analysis Performed by SCAQMD

1. Ozone Data Validation & AnalysisPerformed by SCAQMD Presented by: Mike Hamdan South Coast Air Quality Management District Diamond Bar, CA Presented at: TheTribal Air Monitoring Training , Pechanga Reservation, CA

2. South Coast Air Quality Management District

3. South Coast AQMD South Coast Basin: 4-county region 10,000 sq. miles 16½ million residents Hundreds of thousands ofdiesel vehicles 11,000,000 gasoline vehicles Combined Ports of Long Beach andLos Angeles = nation's largest cargo gateway L o s A n g e l e s S a n B e r n a r d i n o C o u n t y C o u n t y R i v e r s i d e O r a n g e C o u n t y C o u n t y

4. Science & Technology Advancement Atmospheric Measurements Air Monitoring Network Special Monitoring

5. Instruments Configuration Multi-Gas Calibrator Zero Air Generator Sampling Probe Instrument Manifold ESC Data Logger (8832) Minute Polling Database Ozone Video Chart Recorder (Chessell) Generator

6. Ozone Standards • Transfer standards (different levels)– a transportable device or apparatus that is capable of accurately producing or assaying ozone concentrations. These types of instruments undergo a certification process. • Primary standards – a device capable of assaying ozone concentrations by UV photometry in accordance with the Code of Federal Regulations, part 50, Appendix D (40CFR50).

7. Certification/Verification • Calibration - establishes a correction factor to adjust or correct the output of an instrument. This is determined through a comparison between an instrument and SRP at varying levels of ozone. • Certification - establishes traceability of a transfer standard to the SRP. The certification of an instrument requires the results of six calibrations to meet requirements established by U.S. EPA.

8. Continued. • Verification - establishes comparability of a primary standard to the SRP. The verification of an instrument requires the results of one calibration to meet requirements established by U.S. EPA; however, the output of the instrument is not to be corrected based upon the results of the calibration.

9. O3 standards certification and verifications • Primary O3 standard is compared with R9 SRP (standard reference photometer) annually. • O3 field standards (Transfer Standards)are certified every 3 months using verified primary standard. • Flow standards are certified against NIST standards annually.

10. Station Instrument verification & Calibration • Daily zero and span except for Tuesday. • Weekly zero and precision check (every Tuesday) • O3 instrument multi-point calibration every 6 months or as needed. (as is then final) • Gas calibrator (flow controller & O3 generator) certification every 6 months (as is then final).

11. Data Validation Levels • 3 data validation levels. • Level I is done by the station operator. Review chessell data, complet field data sheets, note zero and span values that are exceeding the control limits, document problem with the instruments, document any unusual events at or near the site.

12. Level II & III data validation • Level II and III are done by office staff. • Review data in time series plots. • Backfill missing data from back up system. • Comparison of current data with historical data. • Compare Ozone concentration to meteorology and to ozone reading from nearby sites. • Assign data flags due to fires, construction.

13. Data Screening • Review data that exceeds historical data max. from the site. • Determine if consecutive equal data values are valid. • Check if data falls outside the calibrated range. • Check for blocks of missing data. • Check for consistency of data with season and time of day.

14. Data Invalidation • If pc/span values are outside +/- 7 %. • Not enough data points to calculate valid hourly average. • Station temperatures are not within 20-30 Deg. C. • Data produced during calibration, audit, and maintenance that are not flag by the data logger with proper invalid flag.

15. Contact Information Mike Hamdan South Coast Air Quality Management District mhamdan@aqmd.gov Office: (909) 396-2267 Cell: (909) 967-492315