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Clean Air Markets

Memo and Supplemental Information Regarding Interstate Transport SIPs for the 2015 Ozone NAAQS

On March 27, 2018, EPA provided projected air quality modeling results for ozone in 2023 including projected ozone concentrations at potential nonattainment and maintenance sites for the 2015 ozone NAAQS and projected upwind state contribution data.  States can use these data to develop their implementation plans to assure that emissions within their jurisdictions do not contribute significantly to nonattainment or interfere with maintenance of the 2015 ozone standards in other states.  EPA also provided, as Attachment A to this memorandum, a preliminary list of potential flexibilities in analytical approaches for developing a good neighbor SIP that may warrant further discussion between the EPA and states.

During stakeholder calls in April 2018, the EPA asked stakeholders to provide feedback on the March 27, 2018 memo. The EPA received written comments.  An EPA summary of the comments and the original comment letters are provided below.

Files and Documents:

In response to stakeholder requests, in May 2018, the EPA revised the contribution metric spreadsheet originally posted in March 2018 to include the most recent design values (i.e., 2014-2016) and information regarding “home state” and upwind state collective contribution.