This section provides detailed information about designations and the nonattainment area status for the SO₂ (1971) National Ambient Air Quality Standards (NAAQS). Original areas were designated November 15, 1990.

1. All Designated Area Selections (Nonattainment and Maintenance)
   1. Area/State Information
   2. Area Design Values
   3. State/Area and Design Value Information
   4. State/County/Area Information
   5. State/Area/County List
   6. Area/State/County List


2. Nonattainment Area Selections
   1. Areas by Classification
   2. State/County/Area Information
   3. State/Area/County List
   4. Area/State/County List


3. Maintenance Area Selections (Redesignated from Nonattainment)
   1. Areas by Classification
   2. State/County/Area Information
   3. State/Area/County List
   4. Area/State/County List


4. Area Maps
   Map and GIS shapefile downloads are available from the Downloads page (see sidebar link)
    
   1. National Map of 1971 SO₂ Nonattainment Areas


5. Other Information
   1. Summary Reports
      1. Nonattainment Area Summary Report
      2. Maintenance Area Summary Report
   
   
   2. Designation of Areas for Air Quality Planning Purposes (November 6, 1991
      See 40 CFR PART 81 (PDF)(165 pp, 9.3 MB, About PDF)


6. Federal Register Notices Related to SO₂ (1971 Standard) Areas
   1. Notices Listed By Category
   2. Notices Listed By Area Name
   3. Notices Listed By State then Area
   4. Notices Listed By Date