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SIP Status and Information

SIP Development Process

New or revised National Air Quality Standards: When EPA revises one of the national ambient air quality standards (NAAQS) or establishes a new NAAQS, States and EPA must undertake specific obligations to ensure the NAAQS are met.

  • Within two years after NAAQS promulgation: With input from the states and tribes, EPA must identify or "designate" areas as meeting (attainment areas) or not meeting (nonattainment areas), the standards. Designations are based on the most recent set of air monitoring data.

  • Within three years after NAAQS promulgation: All states must submit plans, known as state implementation plans (SIPs), to show they have the basic air quality management program components in place to implement a new or revised NAAQS, as specified in Clean Air Act section 110. These plans are often called "infrastructure SIPs." Learn more about Infrastructure SIP requirements. See Guidance on Development and Submission of Infrastructure State Implementation Plans for National Ambient Air Quality Standards. (PDF) (62pp, 533k)

  • Within 18-36 months after designations: Due dates for nonattainment area SIPs are based on the area designation date and vary by pollutant and area classification. SIPs for areas designated as nonattainment for SO2, NO2, PM10, and Lead are generally due no later than 18 months from the date of designation. SIPs for Ozone, PM2.5, and CO nonattainment areas are generally due within 36 months from the date of designation. Each nonattainment area SIP must outline the strategies and emissions control measures that show how the area will improve air quality and meet the NAAQS. In addition, the CAA mandates that areas adopt certain specified control requirements. Learn more about SIP requirements for nonattainment areas.

SIPs must be developed with public input, be formally adopted by the state, and submitted by the Governor's designee to EPA. After reviewing submitted SIPs, EPA proposes to approve or disapprove all or part of each plan. The public has an opportunity to comment on EPA's proposed action. EPA considers public input before taking final action on a state's plan. If EPA approves all or part of a SIP, those control measures are enforceable in federal court. If a state fails to submit an approvable plan or if EPA disapproves a plan, EPA is required to develop a federal implementation plan (FIP).

EPA makes electronic copies of state SIP submissions available to the public no later than the time EPA's proposed rulemaking (NPR) on the SIP is published in the Federal Register. In each NPR, EPA provides information on how to locate the electronic docket at www.Regulations.gov Exit Disclaimer for reviewing and submitting comments. Many state air quality management agencies also make SIPs available for public review on state-managed web sites.


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