August 22, 2017 – In response to recommendations from state and tribal representatives, EPA has sent letters to state and tribal leaders outlining the area designations the agency intends to complete by December 31, 2017, for the 2010 primary standard for sulfur dioxide.

• Read Correspondence Between EPA and State and Tribal Representatives
• Technical Support Documents (Chapters 1 - 45)
• EPA Responses to Certain State Designation Recommendations for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard: Notice of Availability and Public Comment Period

• Summary of State Recommendations and EPA Responses (PDF)(41 pp, 839 K)