ABSTRACT
Air pollutant sources can be categorized according to the type of source, their number and spatial distribution, and the type of emissions. Categorization by type includes natural and manmade sources. The list of air pollutants can be subdivided into pollutants that are gases or particulates. Air toxics refer to compounds that are present in the atmosphere and exhibit potentially toxic effects not only to humans but also to the overall ecosystem. Additional air pollutants or atmospheric effects that have become of concern include photochemical smog, acid rain, and global warming. An additional source concept is that of primary and secondary air pollutants. Primary air pollutants are pollutants in the atmosphere that exist in the same form as in source emissions. Secondary air pollutants are pollutants formed in the atmosphere as a result of reactions such as hydrolysis, oxidation, and photochemical oxidation. Economic losses resulting from air pollutants include soiling, damage to vegetation, damage to livestock, and deterioration of exposed materials.
