Overview

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

The National-Scale Air Toxics Assessment, which is based on 1996 emissions data, produced results that are useful in understanding the quality of air and its possible effect on human health nationwide. The assessment looked at 33 air pollutants (a subset of 32 air toxics from the Clean Air Act's list of 188 air toxics plus diesel particulate matter). Specifically, it consisted of 4 steps that produced nationwide estimates of:

(1) the release of these pollutants into the air from various sources;
(2) the concentration of these compounds in the air;
(3) the exposure of populations to this air; and
(4) the risk of both cancer and noncancer health effects resulting from this exposure.

More on the 4 Steps of the Assessment
More Information on the 33 pollutants
EPA's Use of the Results

Download a NATA Technical Fact Sheet in pdf format.
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Overview

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