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Tribal Portal turtle logoThe Clean Air Act

Laws and Regulations


CAA Quick Links

The Clean Air Act (CAA) is designed to “protect and enhance the nation’s air resources so as to promote the public health and welfare and the productive capacity of the population.” The CAA directs EPA to establish national standards for ambient air quality and for EPA, tribes, and states to implement, maintain, and enforce these standards through a variety of mechanisms.

National Ambient Air Quality Standards
Title 1, excluding Section 112 of the CAA, establishes national ambient air quality standards (NAAQS) to limit levels for “criteria pollutants”: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide.

New Source Review (NSR) Permitting Program
Congress established the New Source Review (NSR) permitting program as part of the 1977 Clean Air Act Amendments. NSR requires stationary sources of air pollution to get permits before they start construction. NSR is also referred to as construction permitting or preconstruction permitting.

National Emission Standards for Hazardous Air Pollutants
Title 1, Section 112 of the CAA establishes National Emission Standards for Hazardous Air Pollutants (NESHAPs) to control particular hazardous air pollutants (HAPs).

Mobile Sources
Title II of the CAA pertains to mobile sources, such as cars, trucks, buses, and planes, as well as small engines, like lawn mowers, and large stationary engines used in industry and pipelines. EPA uses technology forcing emissions requirements, reformulated gasoline, automobile pollution control devices, and vapor recovery nozzles on gas pumps, among other mechanisms, to regulate mobile air emission sources. While almost all-mobile source regulation is reserved exclusively for EPA, eligible and approved TAS tribes may participate in enforcing mobile enforcement through vehicle inspection and maintenance programs; states are required to participate in such programs.

Acid Deposition
Title IV of the CAA establishes a sulfur dioxide/nitrogen oxide emissions program designed to reduce the formation of acid rain. Sulfur dioxide releases can be reduced under a “cap and trade” program by granting to certain sources limited emissions allowances, which are below previous levels of sulfur dioxide releases.

Operating Permit Program
Title V of the CAA requires that all “major sources” (and certain minor sources) of air pollution obtain an operating permit, and such sources may be required to submit information about emissions, control devices and the general process at the facility in the permit application. Tribal governments may apply for eligibility to issue and monitor Title V permits.

Stratospheric Ozone Protection
Title VI of the CAA is intended to protect stratospheric ozone by phasing out the manufacture of ozone-depleting chemicals and restricting their use and distribution.

CAA Implementation in Indian country
EPA is authorized to directly implement the CAA in Indian country. Many tribes are monitoring their air for a variety for pollutants, from ozone and particular matter, to mercury and acid rain, as well as developing emission inventories to understand the sources of air pollution on the reservations.


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