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  2. Cross-State Air Pollution

Proposed CSAPR Close-Out

On this page:

  • Rule Summary
  • Rule History
  • Additional Resources

Rule Summary

Determination Regarding Good Neighbor Obligations for the 2008 Ozone National Ambient Air Quality Standard

On June 29, 2018, EPA proposed to determine that the CSAPR Update Rule fully addressed 20 states' interstate pollution transport obligations for the 2008 national ambient air quality standards (NAAQS) for ground-level ozone.

EPA held a public hearing on the proposed rule on August 1, 2018, and the public comment period for the proposal ended on August 31, 2018.

Rule History

June 29, 2018 - Proposed Cross-State Air Pollution Rule Close-Out

EPA proposed that the CSAPR Update Rule fully addresses certain states’ interstate pollution transport obligations for the 2008 ozone NAAQS. 

  • Proposed Determination Regarding Good Neighbor Obligations for the 2008 Ozone National Ambient Air Quality Standard
  • Fact Sheet - Proposed CSAPR Close-Out (pdf) (153.91 KB)

Technical Support Documents (TSDs)

  • Air Quality Modeling Technical Support Document for the Updated 2023 Projected Ozone Design Values (pdf) (5.2 MB, June, 2018) ​
  • Status of 110(a)(2)(D)(i)(I) SIPs for the 2008 Ozone NAAQS (pdf) (189.27 KB, June, 2018)

Previous Actions

  • Memo: Supplemental Information on the Interstate Transport State Implementation Plan Submissions for the 2008 Ozone National Ambient Air Quality Standards under Clean Air Act Section 110(a)(2)(D)(i)(I) (pdf) (585.74 KB) (Signed October 2017)
  • September 7, 2016 - Final Cross-State Air Pollution Rule Update

Additional Resources

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

Cross-State Air Pollution

  • Good Neighbor Plan
  • What is Cross-State Air Pollution?
  • What Does the Clean Air Act Say?
Contact Us about Cross-State Air Pollution
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on August 12, 2024
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