ARB Fact Sheet: Air Pollution and Health

This page last reviewed November 20, 2008

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-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 sensitive to the effects of air pollution, such as children and the elderly. 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, long-term effects, such as cancer, even at low levels. 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 programs for cleaning the air. The ARB works with local air pollution control districts to reduce air pollution from all sources.

What are the health effects of some common air pollutants?

The table below shows the health effects of some of the common pollutants found in our air and examples of some of the sources of these pollutants.




Particulate Matter (PM10: less than or equal to 10 microns)
  • Increased Respiratory Disease

  • Lung Damage

  • Premature Death
  • Cars and Trucks, Especially Diesels

  • Fireplaces, Woodstoves 

  • Windblown Dust from Roadways, Agriculture and Construction 
Ozone (O3)
  • Breathing Difficulties

  • Lung Damage
  • Formed by chemical reactions of air pollutants in the presence of sunlight. Common Sources: Motor Vehicles, Industries, and Consumer Products 
Carbon Monoxide (CO)
  • Chest Pain in Heart Patients

  • Headaches, Nausea

  • Reduced Mental Alertness

  • Death at Very High Levels
  • Any source that burns fuel such as cars, trucks, construction and farming equipment, and residential heaters and stoves.
Nitrogen Dioxide (NO2)
  • Lung Damage 
  • See Carbon Monoxide Sources 
Toxic Air Contaminants
  • Cancer

  • Chronic Eye, Lung, or Skin Irritation

  • Neurological and Reproductive Disorders 
  • Cars and Trucks, Especially Diesels

  • Industrial Sources Such As Chrome Platers

  • Neighborhood Businesses Such As Dry Cleaners and Service Stations

  • Building Materials and Products

If you have questions or comments regarding this web page, please contact Barbara Weller at (916) 445-1324 or via e-mail at

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