The Air District has fined Republic Services $159,000 for 14 air quality violations at the Sonoma Central Landfill in Petaluma.
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.
The Air District has fined Republic Services $159,000 for 14 air quality violations at the Sonoma Central Landfill in Petaluma.
The Air District has issued the following prescribed burn notice effective October 27-31.
- Kamryn, hills near Route 92 and I280, 55 acres, Cal Fire San Mateo-Santa Cruz Unit
- Angel Island State Park, 40 acres, California State Parks
The Bay Area Air District today announced $4,822,770 in funding to SAFETRANS Transportation Inc. to deploy electric school buses serving special education students across Santa Clara County. The grant will support the purchase of 14 zero-emission buses and 11 charging stations, helping to electrify transportation services for some of the region's most vulnerable students.
The Air District has issued the following prescribed burn notice effective October 17 -24, 2025.
- Hill Ranch, mountains west of Novato, 155 acres, Marin County Fire Department
- Kamryn, hills near Route 92 and I280, 55 acres, CALFIRE San Mateo-Santa Cruz Unit
- TomKat Ranch, Pescadero, 49 acres, CALFIRE San Mateo-Santa Cruz Unit
- Tolay Lake Regional Park, southeast of Petaluma, 100 acres, Sonoma County Regional Parks
September 25, 2025
September 22, 2025
September 15, 2025
September 11, 2025
September 10, 2025
September 2, 2025
August 26, 2025
August 26, 2025
August 25, 2025
August 23, 2025
August 22, 2025
August 21, 2025
August 19, 2025
August 18, 2025
August 14, 2025
August 12, 2025
August 11, 2025
July 30, 2025
July 28, 2025
July 23, 2025
July 17, 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.
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
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.
Last Updated: 4/21/2017