Air District Operations

The Air District is taking steps to ensure Bay Area air quality and public health are protected while the shelter-in-place orders are in effect. Permits for businesses adjusting operations to aid in the public health response will also be expedited. Read more... | en Español

About the Air District

Contra Costa County

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

Contra Costa County lies east of the San Pablo Bay, bounded by Alameda County to the south, San Joaquin County to the east, and Solano and Sacramento counties to the north. Four representatives sit on the Air District’s Board of Directors.

Latest News
  • Oct

    October 16, 2020

    Air quality advisory for wildfire smoke extended through Sunday

    The Air District is extending an air quality advisory through Sunday, October 18, due to possible wildfire smoke impacts. There is no Spare the Air Alert in effect and air quality is not expected to be unhealthy. Smoke from the August Complex and Creek Fires are expected to drift into the Bay Area, causing smoky and hazy skies through Sunday.

  • Oct

    October 16, 2020

    Climate Tech Marketplace connects public and private sectors’ innovative climate solutions

    The Air District is hosting a virtual Climate Tech Marketplace event, Cutting-Edge Governments: Leading Investment in the Green Revolution, on October 22 at 10 AM. The event’s keynote speaker is Mariana Mazzucato, author and economist who helped shape the Green New Deal. She will be addressing the roles the public and private sectors must take to ensure growth is more innovation-led, inclusive and sustainable. 

  • Oct

    October 15, 2020

    Air quality advisory for wildfire smoke today and Friday

    The Air District is issuing an air quality advisory today through Friday, October 16, due to possible wildfire smoke impacts. There is no Spare the Air Alert in effect and air quality is not expected to be unhealthy. Smoke from the August Complex Fire and potentially the Creek Fire are expected to drift into the Bay Area, causing smoky and hazy skies today and tomorrow.


Temperatures in and around the San Ramon and Diablo Valleys are warm in the summer and cool in the winter, largely because of their distance from the moderating effect of water bodies and because the California Coast Range blocks marine air flow into the valleys. The Carquinez Strait region remains temperate due to its proximity to water and oceanic air flows. In winter, average daily temperatures are mild, with tule fog common at night. Average summer temperatures are typically mild overnight and warm during the day, with cooler temperatures and stronger winds more common along the western coast. Wind speeds are generally low throughout the region and winds typically blow from northwest to southwest. However, strong afternoon gusts are common in the northern portion of the county around the Carquinez Strait. Annual rainfall averages between 18 and 23 inches across the county.

Contra Costa County’s climate is also affected by regional Bay Area climate influences.

Interactive Air Monitoring Stations Map

Air Quality in Contra Costa 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.

Ozone and PM2.5 infrequently exceed health standards in the portion of Contra Costa County west of the East Bay hills. The San Francisco Bay keeps air temperatures above freezing in winter and well below 100 degrees on even the warmest summer days. 

In eastern Contra Costa County, summer afternoon temperatures frequently approach triple digits, spurring ozone levels to exceed health standards. In winter, PM2.5 can be transported westward through the Carquinez Strait from the Central Valley where it adds to wood smoke, causing health standards to be exceeded.

Interactive Air Quality Forecast Map

Resource Team

Contra Costa County’s Spare the Air Resource Team promotes various ways to reduce air pollution in the local community.

Spare the Air Status
No Wood Burning
Spare the Air Status
  • Monday,

    No Spare the Air Alert in Effect

  • Tuesday,

    No Spare the Air Alert in Effect

Last Updated: 2/14/2019