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Sulfur Dioxide (SO2) Pollution

Primary Sulfur Dioxide NAAQS Implementation Schedule

Anticipated SO2 NAAQS Implementation Milestones for 2010 Primary Standard
Milestone First Round Designations Second Round Designations Third Round Designations Fourth Round Designations
Standard Effective:  June 2010  
Designation Deadline (4 rounds) July 2013 July 2016 December 2017 December 2020
Designations Effective October 2013 September 2016 February/March 2018 March 2021
Infrastructure SIPs Due:  June 2013  
Attainment Plans (Nonattainment SIPs) Due April 2015 March 2018 August/September 2019 September 2022
Attainment Date October 2018 September 2021 February/March 2023 March 2026