ABSTRACT
Although air is generally considered as approximately 20% oxygen and 80% nitrogen (by mole or volume), other substances get into the air, and some of these are referred to as pollutants. Some of the pollutants that have the potential to adversely affect human health at certain concentrations are known as toxic air pollutants (TAPs), or air toxics. The dimensions of toxic exposure are staggering. Not until well after World War II was public attention drawn to toxic exposure. Not until the 1970s did the United States begin to address toxic contamination resulting from the common use of synthetic chemicals that also affected water and food. Incidents, such as Love Canal, in which a major toxic waste dump was discovered beneath a residential community, and Bhopal, India, in which methyl isocyanate was accidentally released into the atmosphere, have sounded a warning. Contaminated communities, or residential areas that are located within the boundaries of a known exposure to some form of pollution are causing a gradual deterioration of the relationship between humans and the ecosystem. An increased awareness of the implications of toxic pollution has led society to confront a new type of threat, that of toxic exposure. The need for information on the toxicity of environmental pollutants is based on the need to protect human health. Toxic exposure may now be considered to be "the plague of our time" [1]. For example, the most comprehensive national study to date of toxic air pollutants shows that the Puget Sound region's urban counties have exceptionally high concentrations of airborne toxins that environmental regulators say put residents at greater risk of cancer. See also:
