Greenhouse Gas Measurement Program

Learn about the Air District's Greenhouse Gas Measurement Program, including the locations of stations in the GHG monitoring network and deployment of the mobile research van.

For decades the Air District has maintained successful monitoring programs for criteria pollutants and toxic compounds. Such programs have been critical in informing Air District actions to improve public health.

In 2015, the Air District launched a Greenhouse Gas, or GHG, measurement program to inform and support its climate protection activities. The overarching goal of the GHG measurement program is to provide the scientific basis that supports rule-making and policy development for reducing GHG emissions in the Bay Area.

In support of this goal, the GHG measurement program has several core objectives:

  • To track trends over time in GHG concentrations for the region;
  • To evaluate and improve the Air District’s regional GHG emissions inventory, especially for methane;
  • To evaluate and improve facility-level GHG emissions estimates and, where possible, evaluate and improve source- and process-level GHG emissions estimates;
  • To educate and inform the public about how the region is contributing to climate change;
  • To provide data and resources to promote climate change research in the region, research that may improve our collective understanding of GHG sources and opportunities for reductions; and
  • To create a successful, comprehensive GHG measurement program to serve as a model for other regions.

GHG Monitoring Network

The Air District has implemented a GHG measurement program to inform its Regional Climate Protection Strategy. The program includes a long-term fixed-site GHG monitoring network to observe ambient concentrations and determine trends of carbon dioxide and methane, as well as carbon monoxide, at four sites. The fixed-site network design is consistent with protocols of international atmospheric monitoring networks and conforms with accuracy and precision standards set by the World Meteorological Organization Global Atmosphere Watch. 

The four fixed sites are located at:

  • Bodega Bay
  • Bethel Island
  • Livermore
  • San Martin

The Bodega Bay site (located at UC Davis Bodega Marine Lab) is located north and upwind of the San Francisco Bay Area. This coastal site often receives clean marine inflow from the west-northwest and hence serves as a regional background site. 

The other three sites are strategically located at exit points for Bay Area air flow that presumably contain well-mixed emissions from upwind local sources. These stations are at San Martin, which is located south and generally downwind of the San Jose metropolitan area; at Livermore, which is close to the cross section of the eastern edge of the Bay Area with California’s Central Valley; and at Bethel Island at the mouth of the Sacramento-San Joaquin Delta. The Livermore station was preceded by a trial station at Patterson Pass in spring of 2016 (April-May).

The knowledge and long-term tracking of GHG contributions from local sources to the regional background will support regional and state climate protection programs and help evaluate their effectiveness over time.

Research Van 

In order to advance the program’s goal of identifying emission “hot spots” and evaluating and improving the regional emissions inventory, the Air District has developed a dedicated mobile GHG monitoring research van. 

The research van is equipped with analyzers that measure methane, carbon dioxide, and nitrous oxide at fast sampling rates. The instruments in the research van can measure local winds and chemical compounds, such as isotopes of methane, carbon monoxide, and ethane, that serve as source tracers.

Such measurements will help identify important sources of methane emissions and distinguish between emissions from biological, combustion-based, and fossil-based GHG sources. Emission ratios and data trends observed from source-specific surveys of GHG sources, especially those of methane, will help verify and improve the region’s GHG emissions inventory, thereby supporting ongoing GHG emission-reduction programs.

Greenhouse Gas Data

The Air District has compiled data from the fixed-site Greenhouse Gas Monitoring Network relating to concentrations of major greenhouse gases and prevailing meteorological conditions over time.

Contact Us

Abhinav Guha
Senior Air Quality Engineer, Planning and Research

415.749.5192

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Last Updated: 10/12/2016