Greenhouse Gas Monitoring Network Update Pat Vaca, Air Pollution Specialist 4-12-2011

1. Greenhouse Gas Monitoring Network UpdatePat Vaca, Air Pollution Specialist4-12-2011

2. Background • The California Global Warming Solutions Act of 2006 (AB32) requires ARB to report and verify GHG emissions inventory • Validation of the inventory is crucial to realizing goals of AB32 • Using “top-down” approach (e.g., based on ambient monitoring and inverse dispersion modeling) to estimate inventory gives 30% higher results than “bottom up” (e.g., based on emission factors x gallons of gas combusted) approach

3. Objectives • Primary: • Establish a pilot network of six GHG monitoring stations • Provide high temporal and spatial resolution of CH4, CO2, and CO • Evaluate if inverse dispersion modeling can be used to improve methane inventory • Secondary: • Long term monitoring may be used to evaluate the effectiveness of new control measures • Additional gasses may be added in the future

4. Pilot Network • Each Monitoring site includes the following measurements: • Methane (CH4), Carbon Dioxide (CO2) by cavity ring-down spectroscopy • Trace Carbon Monoxide (CO) by Gas-Filter Correlation (GFC) with IR absorption • Meteorological Instruments (WS, WD, AT, RH) • 12 months of data will be collected • RD will issue recommendations as to the expansion, relocation, and/or decommission of network at end of initial 12 month period

5. Network Deployment Schedule • Arvin (ARB) – 5/4/10 • Mt. Wilson Observatory (ARB) – 5/18/10 • Madera (SJAPCD) – 6/30/10 • Tranquillity (SJAPCD) – 8/17/10 • Sutter Buttes (ARB) – April 2011 • Tuscan Butte (ARB) – Lease under negotiation

6. Data Analysis • Data Client – ARB Research Division • RD responsible for determining if the data: • Are sufficient for inverse modeling needs • Can be used to develop gridded methane emissions inventory • Can be used to verify ARB methane emission inventory • Data Streams • Analog outputs to data logger. Data are uploaded hourly to AQDASII, validated and uploaded to AQS • Digital results stored onboard instruments, uploaded by field staff, transferred to RD monthly (minute averages and diagnostic parameters for CO, sub-minute results for CH4)

7. Results Example

8. Results (cont)

9. Field Operations • QA/QC • Precision checks analyzed daily (every 11-hours for methane, every 23 hours for TCO) by direct injection from gas bottle at near ambient concentration • 10 minute analysis, average of last five minutes used • Field calibrations performed every six months • High accuracy standard diluted for TCO • NOAA custom blend used for methane, carbon dioxide • Direct injection from bottles, concentrations bracket ambient concentration • Weekly maintenance by field staff • Changing inlet filters, checking instrument diagnostic parameters

10. Precision Checks (methane)

11. Network Developments • First batch of methane data delivered to Marc Fischer from LBL to conduct inverse modeling • Based upon specifications of gas filter correlation (IR absorption), RD has decided to replace analyzers with higher precision/accuracy laser-based instrumentation • Mt. Wilson observatory site scheduled shut down at the end of April • Mt. Wilson monitoring will continue at NASA-JPL laboratory

12. Acknowledgement:Ying Hsu, ARB Research Division Contact Info: Patrick Vaca pvaca@arb.ca.gov 916 324-1146