Air Pollution

Air is a mixture of gases, including nitrogen (79%), oxygen (20%), carbon dioxide (0,03%), and several inert gases: argon (almost 1%), helium, xenon, neon, and crypton. Water vapor exists in varying amounts. Air is a finite resource capable of cleansing itself of many, but not all pollutants. There are six major pollutants: carbon monoxide, sulfur oxides, nitrogen oxides, particulates, hydrocarbons, and photochemical oxidants. The major air pollutants come from three principal sources: transportation, stationary sources (factories and power plants), and industrial processes. Air pollutants are released from vaporization (or evaporation), attrition (or friction), and combustion. Combustion is by far the major producer.