Ozone is created when nitrogen oxides (NO_X) and volatile organic compounds (VOCs) combine in a reaction energized by sunlight. Ground-level ozone is a major constituent of smog. Many states and communities have developed ozone forecasting programs, so that people can take health precautions when ozone levels are high. Some communities have gone even further, taking measures to prevent the production of ozone pollution in the first place.

Motor vehicles, power stations and industrial boilers are the primary sources of NO_X in urban areas. The primary source of VOCs in urban air are the incomplete combustion and spills of fossil fuels. Solvents, paints, cleansers, household products and barbecue lighter fluid also release VOCs into the atmosphere. 

A variety of measures intended to prevent the formation of ozone have been initiated under the auspices of the federal Clean Air Act. Reformulated house paint that contains and releases fewer VOCs, tighter emissions standards for new cars, and cleaner-burning fuels all help prevent the formation of ozone. 

EPA's AIRNow Air Quality Index website contains a section on Ozone Maps, which provides animated maps showing peak and 8-hour ozone concentrations in different regions of the United States.  This website also offers a variety of online fact sheets and other resources related to ozone pollution.

Ozone: Good up High, Bad Nearby is a publication from EPA that is available online. It provides basic information about the differences between ground-level and high-altitude ozone. Another EPA publication with good background information is How Ground-level Ozone Affects the Way We Live and Breathe.

Quick Tips for Improving Ozone Air Pollution and Ozone Fact Sheet, excerpts from the State of the Air 2001, are offered by the American Lung Association. 

Ozone Transport Commission is a group of 13 states working together to reduce ground-level ozone in the Northeast.  These states have taken aggressive regional action against ozone and its contributing pollutants, nitrogen oxides (NOx) and volatile organic compounds (VOCs).

Partners for Clean Air is a midwest coalition of regional businesses, transportation organizations, health advocacy groups and local governments seeking to improve overall air quality and public health by advocating voluntary actions in metropolitan Chicago and northwestern Indiana. Partners for Clean Air administers a voluntary ozone reduction program called Ozone Action Days.

Several states and cities have active governmental and nonprofit ozone prevention programs. For examples, see Galveston-Houston Association for Smog Prevention, Louisiana's OzoneAction! program, New Jersey Ozone Action Partnership and the New York State Department of Environmental Conservation section on Ozone Consumer Information.

How can you do something for clean air? is a set of tips for preventing ozone-forming pollutants that individuals can apply in their daily lives, at work, at home, and while recreating. It is provided online by the City of Austin (Texas) Air Quality Program.

Replacing Solvent Cleaning with Aqueous Cleaning (PDF)

The Milwaukee Journal Sentinel has a special section of their website devoted to ozone prevention and reporting of Ozone Action days.

Last updated October 6, 2003

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