ABSTRACT
Toxic air pollutants are those pollutants which are hazardous to human health or the environment. Some of the pollutants that have the potential to adversely affect human health at certain concentrations are known as TAPs or air toxics. The total nationwide cancer incidence due to outdoor concentrations of air toxics in the United States was estimated to range from approximately 1700 to 2700 excess cancer cases per year. The objective was to assess the magnitude and nature of the air toxics problem by developing quantitative estimates of the cancer risks posed by selected air pollutants and their sources from a national and regional perspective. Because the EPA was so slow in setting standards for HAPs, many states had gone their own ways in regulating air toxics. The slow federal pace in regulating air toxics was in part due to the fact that the EPA, under NESHAP provisions, was required, in setting emission standards, to provide an ample margin of safety.
