California Ambient Air Quality Standards
(CAAQS)
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| Air pollution harms the health of California citizens, damages agricultural
crops, forests and other plants, and creates the haze that reduces visibility. A large body of scientific evidence
associates air pollution exposure with a variety of harmful health effects. That's why the California Air
Resources Board (ARB) and the U.S. Environmental Protection Agency (U.S. EPA) have adopted ambient
(outdoor) air quality standards. These legal limits on outdoor air pollution are designed to protect the health
and welfare of Californians. This site describes California's air quality standards, the air pollutants, and their harmful
effects. For a complete listing of the pollutants and their associated standards check out our Ambient Air Quality Standards Chart. For more detailed information on specific pollutants with established California
ambient air quality standards, click on the name of the pollutant in the list below. |
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Air Pollutants Having Ambient Air Quality
Standards
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| What is an ambient air quality standard? |
| Ambient air quality standards (AAQS) define clean air, and are established
to protect even the most sensitive individuals in our communities. An air quality standard defines the maximum
amount of a pollutant that can be present in outdoor air without harm to the public's health. California
law authorizes the ARB to set ambient (outdoor) air pollution standards (California Health & Safety Code
section 39606) in consideration of public health, safety and welfare. For a brief history of standard setting, click here. |
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| State and National Standards |
| The Federal Clean Air Act requires the U.S. Environmental Protection Agency
to set outdoor air quality standards for the nation. It also permits states to adopt additional or more
protective air quality standards if needed. California has set standards for certain pollutants,
such as particulate matter and ozone, which are more protective of public health than respective federal standards.
California has also set standards for some pollutants that are not addressed by federal standards. |
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| Who is harmed by air pollution? |
| Studies have shown that the elderly and people with certain health conditions
are more susceptible to the harmful effects of air pollution. Infants and children may also be more susceptible
because they spend more time outdoors, are more active and have higher breathing rates. For more information,
check out our Health and
Air Pollution page. |
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| How are ambient air quality standards set? |
| The Children's Environmental
Health Protection Act (CEHPA, California Senate Bill 25, Escutia,
1999) required the ARB and Office of Environmental Health Hazard Assessment to evaluate all ambient air quality
standards by December 2000 to determine whether these standards adequately protect human health, particularly
that of infants and children. The CEHPA also required staff to prioritize those standards found to be inadequate
for full review and possible revision. The evaluation found that health
effects may occur in infants, children, and other potentially susceptible groups exposed to pollutants at
levels near several of the current standards, with PM10, ground-level ozone (O3) and nitrogen dioxide (NO2) receiving the highest priority
for review and possible revision. |
| In June of 2002, staff completed a review of published studies on the health
effects of particulate matter and sulfates, the highest priority pollutant. The ARB adopted staff recommendations for revisions
to the PM10 standard and established a new PM2.5 annual standard. For more information regarding the
PM and Sulfates Standards Review, please follow the link to the PM Standards Review. Staff also reviewed the published scientific literature on ground-level ozone and nitrogen dioxide
and subsequently recommended revisions to standards for these two
pollutants. The revised standards for ozone and nitrogen dioxide went
into effect on May 17, 2006 and March 20, 2008, respectively. Please
follow these links for more information about the Ozone Standard Review and the Nitrogen Dioxide Standards Review. |
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lower priority ambient air quality standards will be reviewed as well. Regulations also require the review
of standards whenever substantial new information pertaining to ambient air quality standards becomes available,
and at least once every five years. |
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| Attainment of Air Quality Standards |
| Click here
to view state and federal designation
maps indicating which geographical areas do or do not
meet air quality standards. |
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For more information on Ambient Air Quality Standards
please contact
Dr. Linda Smith at (916) 327-8225 or email at lsmith@arb.ca.gov.
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