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.

² The listed designation does not reflect EPA action under section 107(d)(4)(A). At the date of enactment of the Clean Air Act Amendments, Jefferson County, Ohio; Brooke County, West Virginia; and Hancock County, West Virginia, were designated Unclassifiable/attainment, by operation of law, under section 107(d)(1)(C) of the Clean Air Act. However, these States and EPA are reviewing whether to confirm or reverse that designation under the process set out under section 107(d)(4)(A) and will publish a separate notice to that effect.

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

³ The 1-hour standard is revoked effective June 15, 2005 for all areas in Ohio. The Canton, Cleveland-Akron-Lorain, Clinton Co, Columbus, Dayton-Springfield, Preble Co, Steubenville, Toledo, Youngstown-Warren-Sharon, and Columbiana Co. 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.

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.

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

¹ December 31, 2011 unless otherwise noted.