ARB's Community Health Program

This page last reviewed July 13, 2010

What is Air Pollution?

Air pollution is a general term used to describe undesirable amounts of particulate or gaseous matter in the atmosphere. Air pollution can be natural or human-made. It occurs naturally during volcano eruptions, forest fires, or dust storms. This has been an occasional problem for humans. However, during the past hundred years, air pollution created by humans has become a major, persistant problem. In California, our cities are among the smoggiest urban areas in the country.

smogWe can see some air pollutants such as the reddish-brown haze in smog; however, other air pollutants, including some of the most dangerous, are invisible. Very small amounts of these pollutants can cause serious health and environmental problems. Air pollution damages crops, reduces property values, and is harmful to humans -- especially children and the elderly. Furthermore, a majority of the state's population resides in low-lying basins where air pollutants tend to persist.

In California, the state Air Resources Board (ARB), the Bureau of Automotive Repair (BAR), and the Department of Pesticide Regulation (DPR) work together with 35 local air districts and the U.S. Environmental Protection Agency (U.S. EPA) to improve and protect air quality in the state.

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