August 13, 2020 – EPA is responding to state recommendations by announcing the Agency's fourth round of intended area designations. EPA’s letters to state governors will initiate a 120-day period for states to provide additional information, if desired, to inform our final designations. EPA is also opening a 30-day public comment period for interested parties to provide input on these designations. The Agency intends to finalize these designations by December 31, 2020.

• Read Correspondence Between EPA and State Representatives
• Technical Support Documents (Chapters 1 - 12)

• Notice of Availability and Public Comment Period: EPA Responses to Certain State Designation Recommendations for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard

• Summary of EPA’s Intended Area Designations for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard – Round 4 (PDF)(3 pp, 166 K)