About the Air District

San Francisco County

Learn about San Francisco County - its climate, potential air pollution concerns, and current air quality. You can also view upcoming Air District events in San Francisco County and read about local efforts to improve air quality.

Latest News
  • Jan

    January 12, 2021

    Air District’s Charge! Program offers $6 million for electric vehicle charging stations

    The Air District is announcing the availability of $6 million through the Charge! program, which provides grant funding to offset the cost of purchasing and installing new publicly accessible chargers for light-duty electric vehicles.

  • Dec

    December 28, 2020

    Air District settles case with Chevron USA Inc.

    The Air District announced today that Chevron USA Inc. has agreed to pay $147,000 to settle violations at its refinery in Richmond. This settlement covers 29 Notices of Violation issued for air quality violations at the Richmond oil refinery during 2016 – 2018.

  • Dec

    December 21, 2020

    Spare the Air Alert extended through Tuesday due to wood smoke buildup

    The Air District is issuing the winter season’s third Spare the Air Alert for tomorrow, Tuesday, December 22, which bans burning wood, manufactured fire logs or any other solid fuel, both indoors and outdoors. Smoke from increased wood burning is expected to cause air quality to be unhealthy with the heaviest impacts in the Santa Clara Valley due to cold overnight temperatures and light winds.

San Francisco County rests at the northern end of the San Francisco Peninsula, bounded by San Mateo County in the south, the Pacific Ocean to the west, San Francisco Bay to the east, and the Golden Gate Bridge to the north. Three San Francisco County representatives sit on the Air District’s Board of Directors.


Because most of San Francisco's landscape is below 200 feet, the marine layer flows across most of the city, creating a cool and windy climate. The southeastern portion of the county, however, tends to be warmer and sunnier, with fewer foggy days. In the winter, average daily temperatures are mild overnight and moderate during the day, while summertime temperatures tend to remain moderate throughout the season. The highest wind speeds are focused along the western coast and generally mild throughout the county. Rainfall averages about 20 inches per year, with the highest amounts reported on the western coast.

San Francisco County's climate is also affected by regional Bay Area climate influences.

Interactive Air Monitoring Stations Map

Air Quality in San Francisco County

Ozone and fine particle pollution, or PM2.5, are the major regional air pollutants of concern in the San Francisco Bay Area. Ozone is primarily a problem in the summer, and fine particle pollution in the winter.

In San Francisco, ozone almost never exceeds health standards and PM2.5 only exceeds the national standard once or twice each year, generally. Being surrounded by water on three sides keeps temperatures within a narrow range, whereby winter low temperatures rarely reach freezing and summer high temperatures stay well below levels where ozone would form and become unhealthy.

Interactive Air Quality Forecast Map

Resource Team

San Francisco County Spare the Air Resource Team promotes ways to reduce air pollution in the local community.

Spare the Air Status

Last Updated: 2/14/2019