Clean Air Act Overview

Government Partnerships to Reduce Air Pollution

The Clean Air Act calls for state, local, federal and tribal governments to implement the Act in partnership to reduce pollution. Roles vary depending on the nature of the air pollution problem.

Government partnerships for:

For Common Pollutants: A State-EPA Partnership

For common pollutants, the law requires EPA to establish health-based national air quality standards to protect people with an "adequate margin of safety."

States are responsible for developing enforceable state implementation plans to meet the standards. In some states such as California, local air pollution districts work with the state to produce air quality plans. Each state plan also must prohibit emissions that significantly contribute to air quality problems in a downwind state.

EPA provides guidance and technical assistance to assist state planning, issues national emissions standards for new stationary sources, and reviews state plans to ensure that they comply with the Act.  Preconstruction permits are required for major new and modified stationary sources.  In most areas, state or local air agencies serve as the CAA permitting authority.  Elsewhere, EPA is the permitting authority.

For Toxic Pollutants: National Standards with a Role for States

Congress called for EPA to issue national limits for toxic air emissions from each category of major sources, and for certain categories of smaller, area sources.  These standards ensure that facilities throughout the nation control their toxic emissions.  States have the option of adopting a program that provides for partial or complete delegation of EPA's authorities to implement and enforce toxic emissions standards; state programs can be no less stringent than the federal requirements. <Learn more about setting standards for toxic air pollutants>

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For Acid Rain: A Federal Program

Congress established a federal acid rain program to cut acid-rain forming emissions from power plants that cross state lines.  The law required EPA to issue the implementing rules, track the trading of emissions allowances, and monitor compliance. <Learn more about the Acid Rain Program>

For Ozone Layer Protection: National Requirements

Congress charged EPA with issuing and enforcing rules to phase out production of ozone-depleting chemicals and to ensure proper recycling, disposal and labeling of these chemicals. <Learn more about requirements to protect the ozone layer>

For Regional Haze: State Plans under EPA Guidance

Congress called for states to adopt enforceable plans to reduce pollutants that damage visibility in national parks and other protected areas.  EPA issues guidance on state planning and required controls, and reviews state plans to ensure that they comply with the Act.  <Learn more about EPA's regional haze program> 

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For Operating Permits: States Usually in the Lead

The CAA requires major stationary sources and certain other sources subject to federal standards to obtain CAA operating permits that contain and assure compliance with all their CAA requirements.  In most areas, state or local air agencies issue the permits.  Elsewhere, EPA or a tribal government is the permitting authority.  <Learn more about operating permits>

The Role of Tribal Governments

Tribal governments can play important roles implementing the Clean Air Act in their areas. If a tribe has the desire and capability to administer one or more Clean Air Act programs and meets certain criteria, the law authorizes EPA to approve the tribe as eligible to implement programs under the Act.   The tribe can then develop and obtain approval of particular Clean Air Act programs from EPA.  Otherwise, EPA generally implements the law in Indian country. EPA's Office of Air and Radiation (OAR) works closely with tribal governments and tribal environmental professionals to increase their capacity to develop and manage their air quality programs by providing training, grants, and technical support. <Learn more about tribes and the Clean Air Act.>

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