Despite significant success in reducing overall pollution levels, air pollution continues to be an important public health problem. Air monitoring shows that over 90 percent of Californians breathe unhealthy levels of one or more air pollutants during some part of the year.

Health effects of Air Pollution

photo of smokeHealth-based ambient air quality standards set by the California Air Resources Board (ARB) identify outdoor pollutant levels that are considered safe for the public - including those most at risk of adverse effects with exposure to air pollution, such as children, the elderly, and people who are active outdoors. The ARB has set standards for eight "traditional" pollutants, such as ozone and particulate matter. In addition to setting standards, the ARB identifies other air pollutants as toxic air contaminants (toxics) - pollutants that may cause serious effects with long-term exposure, such as cancer, when exposure level is low. Most toxics have no known safe levels and some may accumulate in the body from repeated exposures. The Board has identified about 200 pollutants as toxics, and measures continue to be adopted to reduce emissions of toxics. Both traditional pollutants and toxic air contaminants are measured statewide to assess the success of programs for improving air quality. The ARB works with local air pollution control districts to reduce air pollution from all sources.


Past practices of extinguishing every fire combined with impacts related to climate change are leading to larger, more intense, more frequent wildfires that threaten life, safety, and property. Wildfire smoke can result in significant air quality impacts to public health, particularly for at risk groups, and impacts to safety and transportation through diminished visibility on roads and aviation corridors.
Wildfire Smoke, A Guide for Public Health Officials Revised 2021

Wildfire Air Quality Guide for Schools

Wildfire Smoke Considerations for California's Public Health Officials August 2019

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