1 EPA designation replaces State designation.

1 Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2 This date is April 9, 2018, unless otherwise noted.

1 This date is November 15, 1990, unless otherwise noted.

1 This date is October 18, 2000, unless otherwise noted.

2 The 1-hour ozone standard is revoked effective June 15, 2005 for all areas in Missouri. The Kansas City and St. Louis areas are maintenance areas for the 1-hour NAAQS for purposes of 40 CFR part 51 subpart X.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after January 5, 2005, unless otherwise noted.

2 This date is July 2, 2014, unless otherwise noted.

1 Includes areas of Indian country located in each county or area, except as otherwise specified.

2 This date is April 15, 2015, unless otherwise noted.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after January 5, 2005, unless otherwise noted.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 30 days after November 13, 2009, unless otherwise noted.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after October 31, 2011, unless otherwise noted.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is June 15, 2004, unless otherwise noted.

1 This date is July 20, 2012, unless otherwise noted.

2 Excludes Indian country located in each area, unless otherwise noted.

3 Includes any Indian country in each county or area, unless otherwise specified.

4 Attainment date is extended to July 20, 2016.

1 Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2 This date is August 3, 2018, unless otherwise noted.

3 EPA revised the nonattainment boundary in response to a court decision, which did not vacate any designations for the 2015 ozone NAAQS, but which remanded the designation for the identified county. Because this additional area is part of a previously designated nonattainment area, the implementation dates for the overall nonattainment area (e.g., the August 3, 2021 attainment date) remain unchanged regardless of this later designation date.