Identifying and monitoring sources of air pollution is an essential first step toward instituting a workable local pollution-prevention program.  

There are two basic kinds of air pollutants: Primary pollutants such as carbon monoxide are found in the atmosphere in the same form in which they were emitted. Secondary pollutants such as ozone are created in the atmosphere. Gases account for almost 95% by weight of all reported air pollution in the United States. Photochemical smog is a mix of airborne contaminants including primary pollutants and secondary pollutants. 

The Clean Air Act is the principal federal law governing air pollution. Six criteria pollutants are regulated under the auspices of the Clean Air Act: carbon monoxide, nitrogen dioxide, particulates, sulfur dioxide, lead and ozone.

EPA offers a great deal of information about Toxic Air Pollutants through the Office of Air & Radiation. For example, EPA's Air Toxics Website identifies a large range of air pollutants listed by the Clean Air Act, and their sources.  For statistics on annual air-pollution totals and air-quality trends, see EPA's AirTrends website. EPA also reports on its National Air Toxics Assessment, addressing 33 particular toxins.

The Clearinghouse for Inventories and Emissions Factors, another EPA website, furnishes National Emission Inventory data and other emission inventory publications

Air Pollution Emissions Overview from the EPA Office of Air Quality Planning and Standards addresses the general issue of emissions, discusses emission measurement, and provides information on seven specific emissions of particular concern.

The Community Right-to-Know Act became law in 1986, as a portion of the SARA Title III amendments to the Superfund law. Provisions of the law, requiring public access to information on toxins in a community, are explained at an EPA site.

The Toxics Release Inventory Home Page, hosted by the EPA Office of Pollution Prevention and Toxics, provides background information and current annual statistics on toxic chemicals being used, manufactured, treated, transported, or released into the environment.

The Right-to-Know Network allows users to search for toxic pollution in their own areas, using Toxics Release Inventory data and numerous other environmental databases. 

Scorecard is a website from Environmental Defense that offers local pollution information on environmental maps. There are maps for both criteria air pollutants and hazardous air pollutants, as well as other environmental indicators.

The STAPPA/ALAPCO website Clean Air World offers information on air pollutants that includes an extensive list of references on a wide range of specific pollutants.

Individual states also identify, monitor, and regulate air pollutant levels and emissions and many provide online updates on the data they gather and their efforts to reduce toxic pollutants in the air.

On-line Articles and Publications 

EPA makes available the annual Air Quality Trends Report, on the status of and trends in the nation's outdoor air quality and National Air Pollutant Emission Trends, 1900-1998. 

State of the Air 2004, an assessment by the American Lung Association, provides citizens with easy-to-understand air pollution summaries of the quality of the air in their communities. Air quality in counties is assigned a grade ranging from "A" through "F" based on how often their air pollution levels exceed the "unhealthful" categories of the U.S. Environmental Protection Agency’s Air Quality Index for ground-level ozone (smog) pollution and particulate pollution.

Evaluating Exposures to Toxic Air Pollutants: A Citizen's Guide is a basic guide to air toxins and exposure to them, from EPA's Office of Air and Radiation.

The Plain English Guide to the Clean Air Act is an EPA publication that discusses the rationale, details, and performance of the Clean Air Act.

Last updated May 4, 2004

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