The Air District has issued 18 Notices of Violation to MRC for violations of air quality regulations and/or permit conditions for the February 1 fire. This is an ongoing investigation, and more violations may be issued.
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Napa County
Learn about Napa County - its climate, potential air pollution concerns, and current air quality. You can also view upcoming Air District events in Napa County and read about local efforts to improve air quality.
Napa County is nestled in a valley between the Maycamas Mountains in the west and the Vaca Mountains in the east. One Napa County representative sits on the Air District’s Board of Directors.
Latest News
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The Air District is soliciting applications for thirteen seats on its Community Advisory Council. The thirteen open seats represent: Alameda, Contra Costa, San Francisco, San Mateo, Santa Clara, and Solano counties, as well as at-large and youth seats.
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Apply now to join the Community Workgroup for the Refinery Community Particle Fallout Sampling ProgramApril 30, 2025
The Air District is convening a community workgroup to inform development and implementation of our new Particle Fallout Sampling Program for refinery communities. We are looking for people who live or work near the Chevron, Marathon, MRC, Phillips 66, and Valero refineries, or who represent organizations and environmental groups that serve these communities.
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The Air District has fined subsidiaries of Kinder Morgan, Inc., an energy infrastructure company that operates pipelines and fuel terminals throughout North America, $226,990 for air quality violations at two fuel terminals, one in Richmond and another in San Jose.
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March 27, 2025
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Other News Articles
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3/21/2025 Join Webinar to Explore Careers at the Air District
March 21, 2025
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3/13/2025 Air District’s Clean HEET Program now accepting applications
March 13, 2025
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3/5/2025 Air District launches Charge! Program, expanding Bay Area access to electric vehicle chargers
March 5, 2025
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3/3/2025 Notice Regarding Fraudulent Bay Area Commuter Benefits Program Letters
March 3, 2025
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2/13/2025 MRC Refinery Fire Information
February 13, 2025
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2/1/2025 Air quality advisory for smoke from fire at MRC Refinery in Martinez
February 1, 2025
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1/28/2025 Air District asks public not to light firecrackers and fireworks or burn wood over Lunar New Year holiday
January 28, 2025
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1/22/2025 Air District launches new name and branding
January 22, 2025
Climate
The mountains bordering Napa Valley block much of the prevailing northwesterly winds throughout the year. Sunshine is plentiful in Napa County, and summertime can be very warm in the valley, particularly in the northern end. Winters are usually mild, with cool temperatures overnight and mild-to-moderate temperatures during the day. Wintertime temperatures tend to be slightly cooler in the northern end of the valley. Winds are generally calm throughout the county. Annual precipitation averages range from about 24 inches in low elevations to more than 40 inches in the mountains.
Interactive Air Monitoring Stations Map
Air Quality in Napa 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 Napa County, ozone rarely exceeds health standards, but PM2.5 occasionally does reach unhealthy concentrations. There are multiple reasons for PM2.5 exceedances in Napa County. First, much of the county is wind-sheltered, which tends to trap PM2.5 within the Napa Valley.
Second, much of the area is well north of the moderating temperatures of San Pablo Bay and, as a result, Napa County experiences some of the coldest nights in the Bay Area. This leads to greater fireplace use and, in turn, higher PM2.5 levels. Finally, in the winter easterly winds often move fine-particle-laden air from the Central Valley to the Carquinez Strait and then into western Solano and southern Napa County.
Spare the Air Status
Last Updated: 4/21/2017