The purpose of this memorandum is to distribute a non-binding guidance titled, "Guidance for 1- Hour SO₂ Nonattainment Area SIP Submissions." The document is intended to provide guidance and recommendations to state, local and tribal governments for the development of state implementation plans (SIPs) and tribal implementation plans (TIPs) under the 2010 1-hour primary National Ambient Air Quality Standard for Sulfur Dioxide (SO₂ NAAQS). The EPA issued draft guidance on SO₂ implementation in September 2011 so that states and other interested parties would have the opportunity to comment on our preliminary recommendations on how to implement the 1-hour SO₂ NAAQS. Based on the comments received on the September 2011 draft guidance, the EPA is providing this guidance on how to make SIP and TIP submittals addressing areas that are designated as nonattainment.

For more information on the rule please go to 2010 Sulfur Dioxide (SO2) National Ambient Air Quality Standards (NAAQS) Implementation Actions.

• Guidance for 1-Hour Sulfur Dioxide (SO2) Nonattainment Area State Implementation Plans (SIP) Submissions (PDF)(118 pp, 22 MB, April 23, 2014)