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About the Air District

San Mateo County

About the Air District
  1. Air District
  2. About the Air District
  3. In Your Community
  4. San Mateo County

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

Latest News
  • Air District allocates $1.3 million to improve air quality in West Contra Costa County schools
    June 04, 2025

    The Air District's Board of Directors approved allocating $4 million in Community Air Protection Incentives funding to support home and school air filtration programs in Bay Area communities at their June 4 meeting. As part of this initiative, the Air District Board authorized up to $1.3 million of upgrades in public schools in Richmond, North Richmond, San Pablo, and Tara Hills. An additional $1.7 million will be used to expand air filtration upgrades in schools in Bayview-Hunters Point in San Francisco, and $1 million will be allocated to the Air District’s Home Air Filtration program.

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  • Air District extends air quality advisory for wildfire smoke through Thursday
    June 04, 2025

    The Air District is extending an air quality advisory due to wildfire smoke from Canadian wildfires in the Bay Area through Thursday, June 5. Smoke from various Canadian wildfires in Alberta, Saskatchewan, and Manitoba is expected to impact air quality in the Bay Area through Thursday. Conditions can change rapidly and the amount and location of smoke at ground level are 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 through Thursday, June 5.

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  • Air District extends air quality advisory for wildfire smoke through Wednesday
    June 03, 2025

    The Air District is extending an air quality advisory due to wildfire smoke from Canadian wildfires in the Bay Area through Wednesday, June 4. Smoke from various Canadian wildfires in Alberta, Saskatchewan and Manitoba is expected to impact air quality in the Bay Area through Wednesday. Conditions can change rapidly and the amount and location of smoke at ground level are 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 through Wednesday, June 4.

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  • Air District issues air quality advisory for wildfire smoke for Monday and Tuesday
    June 02, 2025

    The Air District is issuing an air quality advisory due to wildfire smoke from Canadian wildfires in the Bay Area for Monday, June 2 and Tuesday, June 3. Smoke from various Canadian wildfires in Alberta, Saskatchewan, and Manitoba is expected to impact air quality in parts of the Bay Area on Monday and Tuesday. 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 on Monday and Tuesday.

    Learn More
Other News Articles

San Mateo County lies in the middle of the San Francisco Peninsula, south of San Francisco County, and north of Santa Clara and Santa Cruz counties. It is bounded by the Pacific Ocean to the west and San Francisco Bay to the east. Two San Mateo County representatives sit on the Air District’s Board of Directors.

Climate

Cool, foggy weather is prevalent along the western coast of the peninsula, particularly during the summer. Summertime average daily temperatures are moderate along the west coast and warm in the county’s east side. In the winter, average daily temperatures across the county range from mild to moderate. Winds are mild, with the highest wind speeds focused along the western coast. Rainfall averages about 20 to 25 inches per year at lower elevations and up to 36 inches in the Santa Cruz Mountains. 

Interactive Air Monitoring Stations Map

Air Quality in San Mateo 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 Mateo County, ozone almost never exceeds health standards, and PM2.5 exceeds the national standard only on about one day each year. San Mateo County frequently receives fresh marine air from the Pacific Ocean, which passes over the coastal hills. In winter, PM2.5 may be transported into San Mateo County from other parts of the Bay Area, adding to wood smoke, which may lead to elevated concentrations, but these are rarely high enough to exceed health standards.

Interactive Air Quality Forecast Map

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Last Updated: 4/21/2017