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Clean Air in Indian Country

The Clean Air Act (CAA)

The CAA is designed to “protect and enhance the nation’s air resources so as to protect 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.

CAA Implementation in Indian Country

EPA is authorized to directly implement the CAA in Indian country. Many tribes have been approved to implement a wide variety of CAA provisions. The Clean Air Act Tribal Authority Rule establishes eligibility requirements for delegations.

Major CAA provisions of interest to tribes include:

  • National Ambient Air Quality Standards
    EPA establishes National Ambient Air Quality Standards (NAAQS) to limit levels of “criteria pollutants”: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone and sulfur dioxide. Tribes may apply to develop a Tribal Implementation Plan (TIP) to identify sources of air pollution and to determine what reductions are necessary to meet federal air quality standards.
  • New Source Performance Standards
    EPA establishes New Source Performance Standards (NSPS), or nationally uniform emission standards, for new and modified stationary sources in particular industrial categories.
  • National Emission Standards for Hazardous Air Pollutants
    EPA establishes National Emission Standards for Hazardous Air Pollutants (NESHAP) to control particular hazardous air pollutants (HAPs).
  • Mobile Sources
    Title II of the CAA pertains to EPA regulation of mobile sources, such as cars, trucks, buses and planes; small engines, like lawn mowers; and large stationary engines used in industry and pipelines. Tribes may participate in mobile source enforcement through vehicle inspection and maintenance programs.
  • Sulfur Dioxide/Nitrogen Oxide Emissions
    Title IV of the CAA establishes a sulfur dioxide/nitrogen oxide emissions program to reduce the formation of acid rain. Tribal governments that own and operate municipal waste combustors, sewage sludge incinerators or large boilers/generators may be subject to these requirements.
  • Major Source Permit Program
    Title V of the CAA requires that all “major sources,” and certain minor sources, of air pollution obtain an operating permit. Tribal governments may be delegated authority to issue and monitor Title V permits.