2024-16123. Clean Air Act Reclassification; Colorado; Reclassification of the Denver Metro/North Front Range 2015 Ozone Nonattainment Area to Serious

Colorado—2015 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area 1	Designation		Classification
	Date 2	Type	Date 2	Type
Denver Metro/North Front Range, CO		Nonattainment	July 24, 2024	Serious.
Adams County.
Arapahoe County.
Boulder County.
Broomfield County.
Denver County.
Douglas County.
Jefferson County.
Larimer County (part).
Including the portion of Rocky Mountain National Park therein and that portion of the county that lies south of a line described as follows: Beginning at a point on Larimer County's eastern boundary and Weld County's western boundary intersected by 40 degrees, 42 minutes, and 47.1 seconds north latitude, proceed west to a point defined by the intersection of 40 degrees, 42 minutes, 47.1 seconds north latitude and 105 degrees, 29 minutes, and 40.0 seconds west longitude, thence proceed south on 105 degrees, 29 minutes, 40.0 seconds west longitude to the inter-section with 40 degrees, 33 minutes and 17.4 seconds north latitude, thence proceed west on 40 degrees, 33 minutes, 17.4 seconds north latitude until this line intersects Larimer County's western boundary and Grand County's eastern boundary.
Weld County	12/30/2021
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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.