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8-Hour Ozone Nonattainment Areas
(1997 Standard)

This page provides detailed information on designations and classifications of 8-hour ozone (1997) nonattainment areas.

On June 8, 2007, the United States Court of Appeals vacated the Subpart 1 portion of the Phase 1 Rule (Court Order) (PDF). On May 14, 2012, the Former Subpart 1 nonattainment areas were classified under Subpart 2 ( 77 FR 28424 (PDF)), effective June 13, 2012.

  1. Nonattainment Area Selections
    1. Area Listings
      1. Areas by Category/Classification
      2. Sorted by State/Area/County
      3. Sorted by Area/State/County
    2. Area Designation Data
      1. Air Quality Data, Population, Counties

  2. Maintenance Area Selections (Previously Nonattainment Areas)
    1. Area Listings
      1. Classified Areas Sorted by Classification
      2. Sorted by State/Area/County
      3. Sorted by Area/State/County
    2. Area Designation Data
      1. Air Quality Data, Population, Counties

  3. Area Maps
    Map and GIS shapefile downloads are available from the Downloads page (see sidebar link)
    1. National Maps
      1. National 8-Hour Ozone (1997) County Map of Maintenance and Nonattainment Areas in the U.S.
      2. National Map of 8-Hour Ozone (1997) Nonattainment Areas
    2. State Maps
      1. Individual State Maps with 8-Hour (1997) Ozone Nonattainment Areas
      2. Individual State Maps with 8-Hour Ozone (1997) Maintenance Areas

  4. Other Information
    1. Summary Reports
      1. Nonattainment Area Summary Report
      2. Maintenance Area Summary Report
      3. Nonattainment Area Summary Report w/ History
    2. Comparison to Other Standards
      1. 8-Hour Ozone (1997 and 2008) and Previous 1-Hour Ozone State/County Detail Report
      2. Sorted by State/Area/County with CO, PM-10, PM-2.5 and Previous 1-Hour Ozone Classifications
      3. Sorted by Area/State/County with CO, PM-10, PM-2.5 and Previous 1-Hour Ozone Classifications
      4. 8-Hour Ozone (1997) Nonattainment and Maintenance Areas and Previous 1-Hour Ozone Areas
      5. 8-Hour Ozone (1997) Nonattainment and Maintenance Areas Compared to PM-2.5 (2006) and PM-2.5 (1997) Nonattainment Areas
    3. 8-Hour Ozone (1997) Unclassifiable Areas
      1. Kansas and Missouri 8-Hour Ozone (1997) Unclassifiable Area Redesignation Federal Register Notices
        2. Proposal (PDF) (February 10, 2005)     Final (PDF) (May 3, 2005)
      2. Syracuse NY 8-Hour Ozone (1997) Unclassifiable Area Redesignation Federal Register Notices
        3. Proposal (PDF) (July 7, 2005)     Final (PDF) (May 15, 2006)

  5. Early Action Compact Areas (Attainment - Previously Deferred Designation)

    6. Based on air quality data from 2005, 2006 and the first three quarters of 2007, the Denver, CO
    Subpart 1 EAC area was designated nonattainment for 8-hour Ozone (1997), effective November 20, 2007
    72 FR 53952 (PDF).

    On February 6, 2008, EPA proposed ( 73 FR 6863 (PDF)) and on April 2, 2008, finalized ( 73 FR 17897 (PDF))
    the designation of the remaining 13 Early Action Compact (EAC) Areas as attainment
    for the 8-hour Ozone (1997) National Ambient Air Quality Standard (NAAQS), effective April 15, 2008.

    1. Area Listings
      1. Areas Sorted by Classification
      2. Sorted by State/Area/County
      3. Sorted by Area/State/County
    2. Area Maps
      1. U.S. Map
    3. Area Designation Data
      1. Air Quality Data, Population, Counties
    4. Summary Report
      1. EAC Summary
    5. Federal Register Notices
      1. Relating to EAC Areas

  6. Areas with a Maintenance Plan Requirement Under Section 110(a)(1) of the CAA

    The Phase 1 final rule to implement the 8-hour Ozone (1997) standard was published on April 30, 2004. The anti-backsliding provisions in that rule set forth specific requirements for areas that are designated attainment for the 8-hour Ozone (1997) standard; and that were - at the time of the 8-hour designations (generally June 15, 2004) - either attainment areas with maintenance plans for the 1-hour standard; or nonattainment for the 1-hour standard.

    Specifically, 40 CFR part 51, section 51.905(a)(3) and (4) requires these areas to submit a maintenance plan under section 110(a)(1) of the CAA. That maintenance plan must demonstrate maintenance out to 10 years after designation. This maintenance plan does not, however, carry with it any conformity obligations (unlike maintenance plans required under section 175A of the Act). The section 110(a)(1) maintenance plan must be submitted within 3 years after designation for the 8-hour Ozone (1997) standard.

    1. Area Listings
      1. Classified Areas Sorted by Classification
      2. Sec. 185A Areas (for Sec 185A definition, click here.)
      3. Incomplete or No Data Areas
      4. Sorted by State/Area/County
      5. Sorted by Area/State/County
    2. Area Maps
      1. Classification by County - U.S. Map
    3. Area Designation Data
      1. Classified
      2. Sec. 185A
      3. Incomplete or No Data
    4. Area Summary Report
    5. Federal Register Notices
      1. 110(a)(1) Maintenance Plans

    Until the 1-hour standard no longer applied, the 1-Hour Ozone Maintenance Areas (Previously Nonattainment Areas) which were subject to the 1-hour standard had maintenance plans required under section 175A, but were not subject to the Section 110(a)(1) maintenance plan provision under 40 CFR part 51, section 51.905(a)(3) and (4). When the 1-hour standard no longer applied, these areas would be required to submit 110(a)(1) maintenance plans under 40 CFR part 51, section 51.905(a)(3) and (4), if they were attainment for the 8-hour standard.

    The Nashville, TN and Greensboro-Winston Salem-High Point, NC and Denver-Boulder, CO 1-Hour Ozone maintenance areas were Early Action Compact (EAC) areas. The 1-hour standard was revoked for the EAC areas on April 15, 2009, one year after the effective date (April 15, 2008) of their designation as attainment for the 8-hour Ozone (1997) standard. At that time, the Denver, CO Subpart 1 EAC area was designated nonattainment for 8-hour Ozone (1997), effective November 20, 2007, and the Nashville, TN and Greensboro-Winston Salem-High Point, NC areas were required to submit a 10-year maintenance plan under section 110(a)(1) of the CAA and the Phase 1 Rule.


  7. Links to Related Topics
    1. More information on 8-hour Ozone (1997) designations
    2. Early Action Compacts

  8. Federal Register Notices Relating to 8-Hour Ozone (1997) Designations and Classifications
    for the 1997 Standard
    1. Designation Notices
      1. Ozone (O3) Standards - Documents from Review Completed in 1997
      2. 8-Hour Ozone Designation Federal Register Notice (April 30, 2004)
      3. 8-Hour Ozone Designation Federal Register Notice (June 18, 2004): Amends April 30, 2004 Notice (PDF)
      4. Phase 2: Final 8-Hour Ozone Implementation Federal Register Notice (November 29, 2005) (PDF)
      5. DC Court of Appeals Ozone Implementation Ruling (December 22, 2006) (PDF)
      6. Phase 2 of the Final Rule To Implement the 8-Hour Ozone National Ambient Air Quality Standard--Notice of Reconsideration (June 8, 2007) (PDF)
      7. DC Court of Appeals Ozone Implementation Rehearing (June 8, 2007) (PDF)
      8. Proposed Settlement Agreement: Denver EAC Designation to Nonattainment, Effective November 20, 2007 (October 1, 2007) (PDF)
      9. Proposed Revision on Subpart 1 Area Reclassification and Anti-Backsliding Provisions Under Former 1-Hour Ozone Standard; Proposed Deletion of Obsolete 1-Hour Ozone Standard Provision (January 16, 2009) (PDF)
      10. Proposed Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area Classifications Approach, Attainment Deadlines and Revocation of the 1997 Ozone Standards for Transportation Conformity Purposes (February 14, 2012) (PDF)
      11. Final Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: Classification of Areas That Were Initially Classified Under Subpart 1; Revision of the Anti-Backsliding Provisions To Address 1-Hour Contingency Measure Requirements; Deletion of Obsolete 1-Hour Ozone Standard Provision (May 14, 2012) (PDF)
      12. Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area Classifications Approach, Attainment Deadlines and Revocation of the 1997 Ozone Standards for Transportation Conformity Purposes (May 21, 2012) (PDF)
      13. Correction: Final Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: Classification of Areas That Were Initially Classified Under Subpart 1; Revision of the Anti-Backsliding Provisions To Address 1-Hour Contingency Measure Requirements; Deletion of Obsolete 1-Hour Ozone Standard Provision (July 25, 2012) (PDF)
    2. Other Associated Federal Register Notices
      1. Clean Data Determination/Attainment Determinations
      2. Attainment Date Extensions
        These extensions modify the dates shown in the nonattainment areas above
      3. Changes to a Higher Classification
      4. All Federal Register Notices
        1. Notices Listed By Category
        2. Notices Listed By Area Name
        3. Notices Listed By State then Area
        4. Notices Listed By Date

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