The Air District is issuing the winter season’s third Spare the Air Alert for Thursday, January 1, which bans burning wood, manufactured fire logs or any other solid fuel, both indoors and outdoors.
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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
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Air District has fined Martinez Refining Company and required enhanced air monitoring data transparencyDecember 23, 2025
The Air District has fined Martinez Refining Company, or MRC, and has required MRC to significantly enhance transparency for air monitoring data for air pollutants around its refinery in Martinez
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Air District fines Chevron $900,000 for air monitoring violationsDecember 02, 2025
The Air District has fined Chevron $900,000 for failing to properly monitor air pollution emissions at its refinery in Richmond.
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Spare the Air Alerts issued for Wednesday & Thanksgiving Day due to wood smoke pollution. Use of all wood-burning devices is prohibited.November 25, 2025
The Air District is issuing the winter season’s first Spare the Air Alerts for Wednesday, November 26, and Thanksgiving Day, which bans burning wood, manufactured fire logs or any other solid fuel, both indoors and outdoors.
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Upcoming Events
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Other News Articles
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11/5/2025 Air District awards $3 million to deploy new electric vehicle chargers in Richmond
November 5, 2025
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10/28/2025 Air District fines Republic Services $159,000 for landfill gas violations
October 28, 2025
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10/27/2025 Air District issues prescribed burn notice for October 27-31
October 27, 2025
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10/22/2025 Air District awards $5M to electrify special education school buses
October 22, 2025
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10/17/2025 Air District issues prescribed burn notice for October 17 - 24, 2025
October 17, 2025
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10/9/2025 Air District fines Marathon Martinez Refinery $372,550 for violations
October 9, 2025
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10/1/2025 Air District Board adopts wood burning and prescribed burning amendments to protect public health and reduce wildfire risk
October 1, 2025
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9/27/2025 Air District issues air quality advisory for wildfire smoke through Sunday
September 27, 2025
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9/25/2025 Air District receives first finance award for excellence in budget process
September 25, 2025
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9/22/2025 Air District issues Spare the Air Alert for Tuesday
September 22, 2025
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9/15/2025 Air District awards $1.18 million to San Ramon Valley Unified School District for new EV school buses, charging infrastructure
September 15, 2025
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9/11/2025 Air District opens Clean Cars for All program with $10 million in funding
September 11, 2025
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9/10/2025 Air District strengthens leadership team, staffing to deliver on permitting priorities & strategic goals
September 10, 2025
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9/2/2025 Air District fines Chemtrade West US LLC $160,000 for air quality violations
September 2, 2025
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.
Spare the Air Status
Last Updated: 4/21/2017