ABSTRACT
The atmosphere has always been polluted to some extent through natural phenomena and/or human activities. Technological advancement, industrial expansion, and urbanization have been the major contributors to global air pollution. Air pollution adversely affects human health and property. The Clean Air Act (CAA) established two levels of National Ambient Air Quality Standards (NAAQSs), primary and secondary standards. Primary air quality standards are promulgated to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary air quality standards are set to protect public welfare, including protection against decreased visibility, and damage to animals, crops, vegetation, and buildings. The major sources of the six criteria pollutants for which NAAQSs exist are transportation fuel combustion, industrial processes, non-transportation fuel combustion, and natural sources such as wildfires. There are three basic strategies for both ambient and indoor air quality control: prevention, dispersion or ventilation, and collection and treatment.
