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  1. Home
  2. Air Quality Implementation Plans

About Air Quality Implementation Plans

On this page:
  • What is a Federal Implementation Plan (FIP)?
    • Current FIPs around the nation
  • What is a Tribal Implementation Plan (TIP)?
  • What is a State Implementation Plan (SIP)?
  • What national standards must SIPs meet?
  • What is included in a SIP?
  • What is EPA's role?
  • Who is responsible for enforcing a SIP?

What is a Federal Implementation Plan (FIP)?

A Federal Implementation Plan (FIP) is an air quality plan developed by EPA under certain circumstances to help states or tribes attain and/or maintain the National Ambient Air Quality Standards (NAAQS) for criteria air pollutants and fulfill other requirements of the Clean Air Act. 

EPA is required to develop a FIP if a state fails to submit a complete implementation plan, or if EPA disapproves a plan as not meeting Clean Air Act requirements. EPA may also develop a FIP for tribal lands if a tribe elects not to develop their own implementation plan, as appropriate.

Current FIPs around the Nation

EPA has developed and implemented the following FIPs:

  • Arkansas (Subpart E)
  • Fort Berthold Indian Reservation Oil and Natural Gas Well Production Facilities (ND)
  • Hawaii Regional Haze
  • Louisiana (Subpart T)
  • Montana Regional Haze
  • Navajo Generating Station (AZ)
  • New Mexico (Subpart GG)
  • North Dakota Regional Haze
  • Oklahoma (Subpart LL)
  • Texas (Subpart SS)
  • Wyoming Regional Haze

What is a Tribal Implementation Plan (TIP)?

A Tribal Implementation Plan (TIP) is an air quality plan developed by a tribe to help attain and/or maintain national air quality standards (NAAQS Standards established by EPA for maximum allowable concentrations of six "criteria" pollutants in outdoor air. The six pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide. The standards are set at a level that protects public health with an adequate margin of safety.) for criteria air pollutants and fulfill other requirements of the Clean Air Act.

Unlike states, tribes are not required to adopt an implementation plan. In the Tribal Authority Rule, EPA recognized that not all tribes will have the need or the desire for an air pollution control program. If a tribe elects not to develop a TIP, EPA will develop a Federal Implementation Plan (FIP) to protect air quality, as necessary.

Learn more:

  • Developing a Tribal Implementation Plan (pdf)
  • Tribal New Source Review Implementation Manual

What is a State Implementation Plan (SIP)?

A State Implementation Plan (SIP) is a collection of regulations and documents used by a state, territory, or local air district to implement, maintain, and enforce the National Ambient Air Quality Standards, or NAAQS, and to fulfill other requirements of the Clean Air Act.

What national standards must SIPs meet?

EPA has established the National Ambient Air Quality Standards for six "criteria" air pollutants - which are widespread common pollutants known to be harmful to human health:

  1. Carbon monoxide pollution
  2. Lead air pollution
  3. Nitrogen oxide pollution
  4. Ozone pollution
  5. Particulate matter pollution
  6. Sulfur dioxide pollution

SIPs provide a plan for implementation, maintenance, and enforcement of the NAAQS in each state. SIPs in states with areas that do not meet the NAAQS must include additional requirements to reduce air pollution in those “nonattainment” areas.

Learn more:

  • NAAQS review process (setting, reviewing, and revising the standards)
  • NAAQS designation process (determining whether areas meet the standards)
  • NAAQS implementation process (attaining and maintaining the standards - includes SIP development)
  • Introduction to EPA's air quality management process

What is included in a SIP?

The contents of a typical SIP fall into three categories:

  1. State-adopted control measures which consist of either state statues and regulations or source-specific requirements (such as orders and consent decrees);
  2. State-submitted "non-regulatory" components (see list of examples below);
  3. Additional requirements promulgated by EPA to satisfy a mandatory requirement in Section 110 or Part D of the Clean Air Act.

Examples of EPA-approved documents and materials associated with the SIP include, but are not limited to:

  • SIP Narratives
  • Infrastructure plans providing for general implementation of a NAAQS
  • NAAQS-specific Part D Nonattainment Area Plans
  • Maintenance plans
  • Vehicle Inspection and Maintenance (I/M) Plans
  • Emissions Inventories
  • Monitoring Networks
  • State Statutes submitted for the purposes of demonstrating legal authority
  • Permitting programs
  • Attainment Demonstrations
  • Transportation Control Measures (TCMs)
  • Contingency Measures
  • 15% Rate of Progress Plans
  • Emergency Episode Plans
  • Visibility Plans

Learn more:

  • List of SIP requirements in the Clean Air Act

What is EPA's role?

The Clean Air Act requires the EPA to review and approve all SIPs that meet the requirements of the Act. Opportunities for public comment are available during the review and approval process for each SIP. If a state does not submit or EPA disapproves a required SIP, the Act also requires EPA to promulgate a Federal Implementation Plan, or FIP, to address the specific requirements.

Learn more:

  • How EPA works with states on SIPs
  • Where to find EPA actions on SIP submittals
  • How to comment on proposed SIPs actions

Who is responsible for enforcing a SIP?

SIPs are generally enforced by the state. However, the EPA is authorized to take enforcement action against violators for federally-approved SIPs. Members of the public can also file citizen suits under the Clean Air Act to address violations of SIPs.

If a SIP has been approved by a state but not yet approved by the EPA, then it is only state-enforceable and not federally-enforceable until approved by the EPA.

Air Quality Implementation Plans

  • About Air Quality Implementation Plans
  • Approved Air Quality Implementation Plans
  • Develop an Air Quality SIP
  • Find a Regional Contact for Air Quality SIPs/FIPS/TIPs
  • Tools for SIP Status
Contact Us about Air Quality Implementation Plans
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on December 5, 2024
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