Greenhouse Gases

Learn about key air pollutants causing global climate change, and their emissions inventories. 

Greenhouse Gases

Many air pollutants have a warming influence on the climate. The Air District prepares emissions inventories of greenhouse gases, or GHGs, known to contribute significantly to climate change, including: 

  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Nitrous oxide (N2O)
  • Hydrofluorocarbons (HFCs)
  • Perfluorocarbons (PFCs)
  • Sulfur hexafluoride (SF6)
  • High Global Warming Potential (GWP) Gases

To learn more about these and other pollutants in the Bay Area you can use the GHGs Descriptions & Sources in California web page provided by the California Air Resources Board.

Regional Greenhouse Gas Emissions Inventory

An overview of San Francisco Bay Area’s emissions inventory of greenhouses from years 1990 to 2050 is provided in the Bay Area Emissions Inventory: Greenhouse Gas Emissions and Forecasts. The pollutants included in the emissions inventory are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

This production-based emissions inventory analyzes GHG emissions that are produced within the Bay Area. The report categorizes GHG emissions from anthropogenic activities into seven major emissions inventory sectors and presents emissions for a base year of 2015. This report describes preliminary work to forecast trends in GHG emissions in the San Francisco Bay Area up to the year 2050. The report describes the Air District’s efforts to include adopted and expected policies to improve the accuracy of regional GHG forecasts. The emissions inventory sectors applied in this report include the following:

  • Transportation
  • Industrial
  • Electricity Generation
  • Commercial and Residential
  • Waste Management
  • Agricultural

Planned Inventory Update (Version: 2025)

The Air District is currently reassessing the regional methane emissions inventory. Recent studies utilizing facility-scale measurements have found that bottom-up inventorying methods are underestimating methane emissions. The Air District is incorporating these measurement-based methane assessments to improve the emissions inventory, wherever feasible.

A comprehensive update to the regional GHG emissions inventory is underway, including review and improvement of estimation methodology, activity data, emissions factors, controls, and forecasting techniques. 

Inventory Reports, Data and Documents

Contact Us

Assessment, Inventory, and Modeling Division

Contact Us

Spare the Air Status

Last Updated: 8/22/2023