Toxic Air Pollutants

EPA has released an important tool to guide further local, state and federal steps to cut toxic air pollution and build upon the significant emissions reductions achieved since 1990. The second National-Scale Air Toxics Assessment (NATA) is a state-of-the-science screening tool that estimates cancer and other health risks from exposure to air toxics.

"Since 1990, we've significantly cut toxic emissions and risks in the United States," said Acting EPA Assistant Administrator for Air and Radiation Bill Wehrum. "This tool will help EPA and states refine our understanding and approaches to further reduce air toxics. With strong industrial standards already in place, our efforts to cut risks from toxic pollution will rely on more advanced technology, more sophisticated analysis, and enhanced cooperation among federal, state and local agencies."

The United States has made significant progress in reducing air toxics from industry, fuels and vehicles, and indoor sources. Since the Clean Air Act was amended in 1990, EPA has issued 96 standards for 174 different types of industrial sources of air toxics, including chemical plants, oil refineries, aerospace manufacturers and steel mills. The agency also has issued regulations for 15 categories of smaller sources, such as dry cleaners, commercial sterilizers, secondary lead smelters and chromium electroplating facilities. Together, these standards are projected to reduce annual emissions of air toxics by about 1.7 million tons from 1990 levels when fully implemented. These reductions are not fully reflected in this assessment, however, because a number of these regulations took effect after 1999.

Vehicles and fuels also emit air toxics. EPA's current and future fuels and vehicles programs will reduce air toxic emissions by another 2.4 million tons in 2020, compared to 1990 levels.

NATA is not designed to be used as the sole basis for regulatory action. The results of the assessment, however, will help EPA and state and local air quality regulators identify pollutants and sources of greatest concern and set priorities for addressing that pollution. NATA also will help identify areas where EPA needs to collect additional information to improve the understanding of risks from air toxics exposure.

NATA covers 177 of the Clean Air Act's list of 187 air toxics plus diesel particulate matter. For 133 of these air toxics (those with health data based on chronic exposure) the assessment includes estimates of cancer or non-cancer health effects including non-cancer health effects for diesel particulate matter.
EPA develops NATA in cooperation with state and local environmental agencies, which provide key information about air toxics emissions.

The assessment estimates that in most of the United States people have a lifetime cancer risk from air toxics between 1 and 25 in a million. This means that out of one million people, between 1 and 25 people have increased likelihood of developing cancer as a result of breathing air toxics from outdoor sources, if they were exposed to 1999 levels over the course of their lifetime (70 years). The assessment estimates that most urban locations have an air toxics lifetime cancer risk greater than 25 in a million. Risk in transportation corridors and some other locations is greater than 50 in a million. In contrast, one out of every three Americans (330,000 in a million) will develop cancer during a lifetime, when all causes (including exposure to air toxics) are taken into account.

The second NATA expands on EPA's first national-scale assessment with a more complete emissions inventory and the latest health effects information. The first assessment, based on 1996 data, was release in 2002. The methods used for the assessments were peer-reviewed and endorsed by EPA's Science Advisory Board in 2001.

EPA plans to develop new national-scale assessments as inventory data from subsequent years become available. The next such analysis will focus on exposure and risks from 2002 emissions.
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