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Transportation Conformity: A Basic Guide for State and Local Officials

Appendix A: Health Effects of Pollutants

EPA has established standards8 for four transportation-related pollutants:

The standards are based upon EPA's assessment of the health risks associated with each of the pollutants on at-risk populations. These assessments are based upon short and long-term scientific studies by noted health professionals and medical research institutions. At-risk groups include children, the elderly, persons with respiratory illnesses, and even healthy people who exercise outdoors.

Air pollution often involves a complex set of chemical reactions including combinations of pollutants and other factors such as weather and geography. Each pollutant plays a different role in the overall air quality in any given geographic area. Below is a brief overview of the key transportation-related pollutants.

8 National Ambient Air Quality Standards (NAAQS)

Updated: 3/14/2012
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