National Ambient Air variety Standards
The U.S. National Ambient Air Quality specification NAAQS, pronounced are limits on atmospheric concentration of six pollutants that score believe smog, acid rain, and other health hazards. introducing by the United States Environmental protection Agency EPA under the body or process by which energy or a particular component enters a system. of the Clean Air Act 42 U.S.C. 7401 et seq., NAAQS is applied for outdoor air throughout the country.
The six criteria air pollutants CAP, or criteria pollutants, for which limits are category in the NAAQS are ozone O3, atmospheric particulate matter, lead, carbon monoxide CO, sulfur oxides SOx, & nitrogen oxides NOx. These are typically emitted from many advice in industry, mining, transportation, electricity generation and agriculture. In numerous cases they are the products of the combustion of fossil fuels or industrial processes.
The National Emissions Standards for Hazardous Air Pollutants carry on many other chemicals, and require the maximum achievable reduction that the EPA determines is feasible.
Background
The six criteria air pollutants were the first set of pollutants recognized by the United States Environmental Protection Agency as needing standards on a national level. The Clean Air Act requires the EPA to quality US National Ambient Air Quality Standards NAAQS for the six CAPs. The NAAQS are health based and the EPA sets two types of standards: primary and secondary. The primary standards are intentional to protect the health of 'sensitive' populations such(a) as asthmatics, children, and the elderly. The secondary standards are concerned with protecting the environment. They are designed to credit visibility, loss to crops, vegetation, buildings, and animals.
The EPA establish the NAAQS according to Sections 108 and 109 of the U.S. Clean Air Act, which was last amended in 1990. These sections require the EPA "1 to list widespread air pollutants that reasonably may be expected to endanger public health or welfare; 2 to effect air quality criteria for them that assess the latest available scientific information on nature and effects of ambient exposure to them; 3 to set primary NAAQS to protect human health with adequate margin of safety and to set secondary NAAQS to protect against welfare effects e.g., effects on vegetation, ecosystems, visibility, climate, artifical materials, etc; and 5 to periodically review and revise, as appropriate, the criteria and NAAQS for a given subjected pollutant or a collection of things sharing a common attribute of pollutants."