Air pollution can harm our bodies in many ways. Air pollution causes a range of short-term respiratory symptoms, including coughing, throat irritation, chest tightness, wheezing, and shortness of breath as well as long-term damage and aggravation of other diseases.

Who is most vulnerable?

Children, seniors, and people with asthma or other lung and heart conditions are most vulnerable to the effects of air pollution. Children are more vulnerable than adults because their lungs are still developing, they spend more time outdoors, and they breathe faster than adults do. Adults who work or exercise outdoors for extended periods of time are also vulnerable.

Recent studies have shown that air pollution can harm lung development in children and can contribute to early childhood asthma. Higher air pollution levels have been associated with a higher incidence of heart problems, including heart attacks. Toxic air pollutants can increase the risk of developing cancer and can cause non-cancer health effects.

What are the pollutants of most concern?

In Santa Barbara County, the pollutants of most concern are:

  • Ground-level ozone — the principal component of smog
  • Fine particles in the air known as particulate matter, and
  • Air toxics — chemicals in the air that can cause cancer and other health problems.

Air quality standards define clean air and tell us how much of a substance can be in the air without causing harm. Federal standards have been set for seven pollutants, including ozone and particluates; California standards have been set for those seven plus four more. In most cases, California’s standards are more protective of health than the federal standards. Santa Barbara County fails to meet the California 8-hour ozone standard (implemented in May 2006) and the California standard for particulate matter less than 10 microns in diameter (PM10). As a result, we are required to adopt Clean Air Plans to show how we will reduce air pollution in order to attain the clean air standards and we are required to report the Air Quality Index (AQI), a scale of actual levels of ozone and other common pollutants in the air in relation to their health standard. Learn more about air quality standards and our attainment status at Meeting Air Quality Standards.

Air quality standards have not been established for air toxics. Instead, regulations aim to reduce their health risk. Learn more at Air Toxics.


On October 1, 2015, the U.S. Environmental Protection Agency (EPA) announced a new eight-hour standard of 70 ppb for ground-level ozone, one of the principal components of smog. For more information, see New Ozone Standard.

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Ozone is a gas created when NOx (nitrogen oxides) and VOCs (volatile organic compounds) react chemically in the presence of sunlight and heat. Ozone is a primary ingredient of smog.

Ozone occurs in two layers of the Earth’s atmosphere.

Good up high: in the stratosphere 10 to 30 miles above the surface of the Earth, the stratospheric ozone layer protects life from harmful ultraviolet rays.

Bad nearby: on the ground, up to 10 miles above the Earth’s surface, in the troposphere, ground-level ozone can damage human health, crops, and buildings.

Santa Barbara County’s ozone season typically runs from April through October. To read more about ozone and our health, including how ozone damages our lungs, and who is at risk, see Ozone Air Pollution and Health.


usepa-particlesize-600Fine mineral, metal, soot, smoke, and dust particles suspended in the air can harm our lungs. For health reasons, we are most concerned with inhalable particulate matter less than 10 micrometers in diameter (PM10), and less than 2.5 micrometers in diameter (PM2.5). Particles of these sizes can permanently lodge in the deepest and most sensitive areas of the lungs, and can aggravate many respiratory illnesses including asthma, bronchitis, and emphysema. High levels of particle pollution have also been associated with a higher incidence of heart problems, including heart attacks.

For more information on particle pollution in Santa Barbara County, see Particle Pollution and Health.

Air Toxics

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Air toxics are chemicals released into the air that are known or suspected to cause cancer or other serious health problems. Examples of air toxics include mercury, asbestos, and benzene. Vehicle exhaust contains high amounts of air toxics, and diesel exhaust particulate is considered the number one airborne carcinogen in California. See information on APCD’s funding programs for cleaner diesel engines designed to reduce diesel exhaust emissions. See our Air Toxics section for information on air toxics and health and the District’s air toxics program.

When should I be concerned?

Air quality advisories are issued to alert the public about poor air quality. An Air Quality Watch is issued when there is potential for poor air quality in one or more areas of the county; an Air Quality Warning is issued when there is already poor air quality. An Advisory may be issued when high winds are producing high particle levels, or when smoke from a wildfire is affecting the county. If you wish to receive the District’s air quality advisories via email, you may Subscribe. You can also follow us on Twitter (@OurAirAdvisory).

You may wish to reduce your outdoor activities if an air quality advisory is issued for your area or if you can see a lot of dust, exhaust, or smoke in the air. Do not use toxic chemicals in poorly ventilated areas.

More Information

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For more information or to request materials, including posters and factsheets, contact Mary Byrd at (805) 961-8833.