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
  • The Air District is lifting an air quality advisory for the Bay Area due to wildfire smoke that was originally scheduled to last through today, Monday, July 14. Over the weekend, smoke from the Butler and Green wildfires had been moving down the Sacramento Valley and impacting air quality in portions of the Bay Area. However, as of Monday morning, the Bay Area is experiencing strong onshore winds, and smoke has remained mostly outside of the region. Air quality has been in the Good Air Quality Index category. Moderate onshore winds are expected to continue into Tuesday, keeping the smoke outside of the Bay Area. As the week progresses, these onshore winds will turn southerly in northern California, and this also is expected to keep the smoke from moving towards our region.

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  • The Air District is extending an air quality advisory for the Bay Area due to wildfire smoke from fires in northern Sacramento Valley through Monday, July 14. Smoke from the Butler and Green wildfires is still moving down the Sacramento Valley and is expected to continue to impact air quality in portions of the Bay Area on Sunday and Monday. Areas that are expected to be most impacted will be parts of the North Bay and East Bay and higher elevation locations. Conditions can change rapidly and the amount and location of smoke at ground level is hard to predict. The public can check for real-time smoke pollution levels in their local area with the U.S. EPA’s Fire and Smoke Map.  Smoky, hazy skies may be visible, the smell of smoke is possible and air quality may become unhealthy at times on Sunday and Monday

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  • The Air District is extending an air quality advisory for the Bay Area due to wildfire smoke from fires in northern Sacramento Valley through Saturday, July 12. Smoke from the Butler and Green wildfires is moving down the Sacramento Valley and is expected to continue to impact air quality in portions of the Bay Area on Saturday. Conditions can change rapidly and the amount and location of smoke at ground level is hard to predict. The public can check for real-time smoke pollution levels in their local area with the U.S. EPA’s Fire and Smoke Map. Smoky, hazy skies may be visible, the smell of smoke is possible and air quality may become unhealthy at times on Saturday

     
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  • The Air District is issuing an air quality advisory for the Bay Area due to wildfire smoke from fires in northern Sacramento Valley for today, Thursday, July 10, and Friday, July 11. Smoke from the Butler and Green wildfires has been moving down the Sacramento Valley and is expected to impact air quality in the eastern portion of the Bay Area down to Santa Clara Valley on Thursday and Friday. Conditions can change rapidly and the amount and location of smoke at ground level is hard to predict. The public can check for real-time smoke pollution levels in their local area with the U.S. EPA’s Fire and Smoke Map. Smoky, hazy skies may be visible, the smell of smoke is possible and air quality may become unhealthy at times on Thursday and Friday

     

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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.

Climate

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. 

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

Spare the Air Status

Last Updated: 4/21/2017