The EPA on Wednesday, June 24, released the latest version of the agency's tool for estimating health risks from air toxics. The National Air Toxics Assessment, based on 2002 air emissions data, helps federal, state, local and tribal governments identify areas and specific pollutants for further evaluation to better understand risks they may pose, according to an agency press release.

The report assessed 180 air toxics plus diesel particulate matter from stationary sources of all sizes and from mobile sources such as cars, trucks, buses and construction equipment.

The 2002 assessment estimates that most people in the United States have an average cancer risk of 36 in 1 million if exposed to 2002 emissions levels over the course of their lifetime. In addition, 2 million people have an increased cancer risk of greater than 100 in 1 million. Benzene was the largest contributor to the increased cancer risks.

The assessment provides broad estimates of risk over geographic areas of the country, and not definitive risks to specific individuals, the agency pointed out in its release, noting, "The results are best used to prioritize pollutants and areas for further study, not as the sole basis for regulation or risk reduction activities."