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Clean Air Markets

Final CSAPR Close-Out

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Rule Summary

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

EPA is finalizing a determination that the existing Cross-State Air Pollution Rule Update for the 2008 Ozone National Ambient Air Quality Standards (NAAQS) (CSAPR Update) fully addresses the Clean Air Act’s “good neighbor” requirements for 20 states with respect to the 2008 ground-level ozone standard. The final rule determines that 2023 is an appropriate future analytic year to evaluate further good neighbor requirements. The rule uses the latest data and modeling to assess air quality for 2023 and finds that there will be no remaining nonattainment or maintenance areas for the 2008 Ozone NAAQS in the eastern United States. As a result, the rule determines that, with the CSAPR Update fully implemented, these 20 states are not expected to contribute significantly to nonattainment or interfere with maintenance of the NAAQS in any other state. With this determination, EPA has no obligation to establish additional requirements for sources in these states to further reduce transported ozone pollution under the 2008 ozone NAAQS.  In addition, the 20 covered states do not need to submit state implementation plans (SIPs) that would establish additional requirements beyond the existing CSAPR Update.

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Rule History

September 13, 2019 – CSAPR Close-Out Vacated

The US Court of Appeals for the DC Circuit issued a judgment vacating the CSAPR Close-Out.

December 6, 2018 – Final Cross-State Air Pollution Rule Close-Out

EPA is finalizing a determination that the exiting CSAPR Update fully addresses certain states’ interstate pollution transport obligations for the 2008 ozone NAAQS. 

Technical Support Documents (TSDs)

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