Revised Cross-State Air Pollution Rule Update

Final Rulemaking

On this page:

• Rule Summary
• Rule History
• Previous Actions
• Additional Resources

Rule Summary

On March 15, 2021, EPA finalized the Revised Cross-State Air Pollution Rule Update for the 2008 ozone National Ambient Air Quality Standards (NAAQS). Starting in the 2021 ozone season, the rule will require additional emissions reductions of nitrogen oxides (NO_X) from power plants in 12 states, improving air quality for millions of Americans.

EPA estimates that the Revised CSAPR Update will reduce NO_X emissions from power plants in 12 states in the eastern United States by 17,000 tons in 2021 compared to projections without the rule, yielding public health and climate benefits that are valued, on average, at up to $2.8 billion each year from 2021 to 2040.  

Rule History

March 15, 2021 - Final Revised Cross-State Air Pollution Rule Update

EPA is issuing new or amended Federal Implementation Plans (FIPs) in 12 states to address air quality impacts of the interstate transport of ozone air pollution in the eastern United States. The final rule was published in the Federal Register on April 30, 2021.

• Revised Cross-State Air Pollution Rule Update Final Rule
  • Correction to Revised CSAPR Update Final Rule Preamble (Published June 4, 2021)
• Revised CSAPR Update Factsheet for Final Rule (pdf) (319.26 KB)  (Updated May 3, 2021)
• Final Table of State Budgets
• Recall of 2021-2024 Group 2 Allowances for Group 3 Sources (pdf) (145.25 KB)  (Updated May 3, 2021)
  • Updated supplemental information on recall of CSAPR NOx Ozone Season Group 2 allowances (xlsx) (204.2 KB) (Updated July 19, 2021)
• Allowance Bank Conversion Fact Sheet (pdf) (157.7 KB)  (Updated May 3, 2021)
• The Safety Valve: A Voluntary Process for Group 3 Sources to Convert Additional Banked Allowances (pdf) (172.28 KB) (Updated March 16, 2022)
• Regulatory Impact Analysis Final Rule
• Power Sector Modeling Final Rule
• 2021 and 2022 Important Dates 

Technical Support Documents (TSDs)

• Air Quality Modeling TSD for the Revised CSAPR Update (pdf) (3.39 MB)
  • Final Data File with Ozone Design Values and Ozone Contributions (xlsx)
• Revised CSAPR Update Allowance Allocations TSD (pdf) (298.32 KB)
  • Updated Unit-Level Allocations and Underlying Data for the Revised CSAPR Update for the 2008 Ozone NAAQS (xls)
    (Updated May 4, 2021 to include unit-level allocations of supplemental allowances)
• Assessing Non-EGU Emission Reduction Potential TSD for the Revised CSAPR Update (pdf) (646.63 KB)
• Ozone Transport Policy Analysis TSD for Revised CSAPR Update (pdf) (1.94 MB)
  • State Emission Budget Calculations and Engineering Analytics Final Rule (xls)
• EGU NOx Mitigation Strategies TSD for the Revised CSAPR Update (pdf) (520.16 KB)
• Preparation of Emissions Inventories for 2016v1 North American Emissions Modeling Platform TSD (pdf) (9.33 MB)
• Status of CAA Section 110(a)(2)(D)(i)(I) SIPs for the 2008 Ozone NAAQS for States Covered by the Revised CSAPR Update, Final Rule TSD (pdf) (165.02 KB)
• Estimating PM2.5 and Ozone - Attributable Health Benefits TSD (pdf) (3.68 MB)
  • ​ Study Information Table (xlsx)

Additional supporting information and data for the listed TSDs are available in the official docket.

Previous Actions - Proposed Rulemaking

October 15, 2020 - Proposed Revised Cross-State Air Pollution Rule Update

EPA proposed to issue new or amended Federal Implementation Plans (FIPs) to revise emission budgets in 12 states to address air quality impacts of the interstate transport of ozone air pollution.

• Proposed Revised Cross-State Air Pollution Update Rule
• Fact Sheet: Revised Cross-State Air Pollution Rule Update for the 2008 NAAQS (pdf) (316.2 KB)
• Proposed Table of State Budgets
• Regulatory Impact Analysis Proposed Rule
• Power Sector Modeling

Technical Support Documents (TSDs)

• Air Quality Modeling TSD for the Proposed Revised Cross-State Air Pollution Rule Update
  • Data File with Ozone Design Values and Ozone Contributions (xlsx)
• Allowance Allocation Under the Proposed Revised CSAPR Update Rule TSD
  • Unit-Level Allocations and Underlying Data for the Revised CSAPR Update for the 2008 Ozone NAAQS (xls)
• Assessing Non-EGU Emission Reduction Potential TSD
• Ozone Transport Policy Analysis Proposed Rule TSD
  • State Emission Budget Calculations and Engineering Analytics (xls)
• EGU NO_X Mitigation Strategies Proposed Rule TSD
• Preparation of Emissions Inventories for 2016v1 North American Emissions Modeling Platform TSD
• Status of CAA Section 110(a)(2)(D)(i)(I) SIPs for the 2008 Ozone NAAQS for States Covered by the proposed Revised CSAPR Update TSD

Additional supporting information and data for the listed TSDs are available in the official docket.

Additional Resources

• Cross-State Air Pollution Rule Update
• Cross-State Air Pollution Rule