ABSTRACT
This chapter presents the reader with information on pollutants and categorizes their sources by the media they threaten. The subsections focus on a number of the most significant air quality challenges: ozone and carbon monoxide, airborne particulates, airborne toxics, sulfur dioxide, acid deposition, and indoor air pollutants. Since auto travel and the number of small sources of VOCs are expected to increase, even strenuous efforts may not sufficiently reduce emissions of ozone and carbon monoxide. Since most people spend 90% of their time indoors, exposure to unhealthy concentrations of indoor air pollutants is often inevitable. Industrial wastes discharged indirectly are treated to remove toxic pollutants. Nonpoint sources are also a major source of toxics, among them are pesticide runoff from agricultural areas, metals from active or abandoned mines, gasoline, and asbestos from urban areas. Particulates in the air include dust, smoke, metals, and aerosols. Major sources include steel mills, power plants, cotton gins, cement plants, smelters, and diesel engines.
