Motor vehicles, air pollution, and public health.

Over the past decade, an increasing body of scientific evidence has accrued associating outdoor air pollution with certain types of cancer. Specifically, two major large prospective epidemiological studies first published in the early to mid-1990s and, in the case of one study, recently confirmed with a larger data base, found an association between exposure to particulate air pollution and lung cancer deaths 2 . These findings are consistent with the extensive body of toxicological and epidemiological scientific evidence linking particulate matter with lung cancer from studies of workers occupationally exposed to diesel particulate exhaust (e.g. railroad workers, bus and truck maintenance workers). Air pollution from motor vehicles also includes emissions of a variety of toxic organic compounds such as benzene. Benzene has been linked to increased risk of leukemia in workers who were occupationally exposed to benzene in various manufacturing processes, and is listed as a known human carcinogen in the National Toxicology Program Ninth Report on Carcinogens.