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.

• 2015 Ozone NAAQS Memo (signed March 2018)
  • 2015 Ozone NAAQS Interstate Transport Assessment Design Values and Contributions(1 pg, 336 K)
  • Comments Received on EPA's March 27, 2018 Memo
  • Summary of Comments Received on EPA's March 27, 2018 Memo
• Analysis of Contribution Thresholds Memo (signed August 2018)
  • Contribution Threshold Analysis for 2015 NAAQS Ozone Transport(1 pg, 22 K)
• Considerations for Identifying Maintenance Receptors Memo (signed October 2018)
  • Ozone Monitoring Site Design Values for 2008 through 2017 and for 2023 (100 K)
  • State-Level Annual Anthropogenic NOx and VOC Emissions for 2011 through 2017 and for 2023(173 K, Updated November 2018)