On this page:

• Rule Summary
• Rule History
• Additional Resources

Rule Summary

On September 7, 2016, the EPA finalized an update to the Cross-State Air Pollution Rule (CSAPR) for the 2008 ozone National Ambient Air Quality Standards (NAAQS) by issuing the final CSAPR Update.  Starting in May 2017, this rule will reduce summertime (May - September) nitrogen oxides (NO_X) emissions from power plants in 22 states in the eastern U.S., providing up to $880 million in benefits and reducing ground-level ozone exposure for millions of Americans.  The rule will reduce air quality impacts of ozone pollution that crosses state lines and will help downwind areas meet and maintain the 2008 ozone air quality standard.

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Rule History

September 13, 2019 - CSAPR Update Remanded

The US Court of Appeals for the DC Circuit remanded the CSAPR Update to the EPA to address the court’s holding that the rule unlawfully allows significant contribution to continue beyond downwind attainment deadlines.

• US Court of Appeals Opinion

September 7, 2016 - Final Cross-State Air Pollution Rule Update

The EPA finalized Federal Implementation Plans (FIPs) in the CSAPR Update to address air quality impacts of the interstate transport of ozone air pollution in the eastern United States.

• Final Cross-State Air Pollution Rule Update
• Fact Sheet
• Key Changes and Improvements Fact Sheet
• Regulatory Impact Analysis
• Power Sector Modeling

Technical Support Documents (TSDs)

• Air Quality Modeling TSD for the Final Cross-State Air Pollution Rule Update
  • 8-Hour Ozone Model Performance Statistics by Monitoring Site for the 2011 Base Year CAMx Model Simulation for the Final CSAPR Update(1 pg, 314 K)
  • Data File with Ozone Design Values and Ozone Contributions(1 pg, 338 K)
• EGU NOX Mitigation Strategies Final Rule TSD
• Status of 110(a)(2)(D)(i)(I) SIPs for the 2008 Ozone NAAQS
• Ozone Transport Policy Analysis Final Rule TSD
  • Appendix E: Budget Calculations(1 pg, 330 K)
• Assessment of Non-EGU NOx Emission Controls, Cost of Controls, and Time for Compliance Final TSD
• CSAPR Allowance Allocations Final Rule TSD
  • Unit-Level Allocations and Underlying Data for the CSAPR Update for the 2008 Ozone NAAQS(1 pg, 2 MB)

Petitions for Reconsideration

• Petitions for Reconsideration Received for the CSAPR Update

Previous Actions:

• November 16, 2015 - Proposed Cross-State Air Pollution Rule Update

• July 23, 2015 - Notice of Data Availability

• January 2015 - Memo and Information Sharing

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Additional Resources

• Cross-State Air Pollution Rule
• Interstate Air Pollution Transport

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