Greenhouse Gas Monitoring Network Update Pat Vaca Air

Greenhouse Gas Monitoring Network Update Pat Vaca, Air Pollution Specialist 4 -12 -2011 1

Background § The California Global Warming Solutions Act of 2006 (AB 32) requires ARB to report and verify GHG emissions inventory § Validation of the inventory is crucial to realizing goals of AB 32 § 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 2

Objectives § Primary: – Establish a pilot network of six GHG monitoring stations – Provide high temporal and spatial resolution of CH 4, CO 2, 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 3

Pilot Network § Each Monitoring site includes the following measurements: – Methane (CH 4), Carbon Dioxide (CO 2) by cavity ringdown 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 4

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 5

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 CH 4) 6

Results Example 7

Results (cont) 8

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 9

Precision Checks (methane) 10

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 11

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