Responses to ozone pollution vary from one individual to another, sometimes for reasons we don’t yet understand. The U.S. Environmental Protection Agency (EPA) estimates that 5 to 20 percent of the total U.S. population has an unexplained greater susceptibility (American Lung Association 2000)
The EPA has designated ozone one of six "criteria air pollutants" and therefore a pollutant that must be kept in check. Yet few state governments have enforced regulations designed to bring ozone air pollution under control. Tropospheric ozone levels in the more polluted regions of the Northern Hemisphere appear to be rising at about 1 percent per year (Turco 1997) The American Lung Association reports that scientists’ estimates of the annual number of deaths in the United States associated with air pollution range from 50,000 to 100,000. (American Lung Association 2001) While another form of air pollution, particulate matter, is the one most prominently linked to premature death, ozone pollution plays an important role as well in this threat to human health and well-being.