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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	October 30, 2022
Attainment Date	October 2018	September 2021	February/March 2023	April 30, 2026

Primary Sulfur Dioxide NAAQS Implementation Schedule

Sulfur Dioxide (SO2) Pollution