40 CFR 81.316

Regulations last checked for updates: Feb 10, 2026

Title 40 - Protection of Environment last revised: Dec 22, 2026

View all text of Subpart C [§ 81.300 - § 81.356]

§ 81.316 - Iowa.

Iowa—TSP

Designated area	Cannot be classified	Better than national standards
Central portion of Waterloo	X
Cedar Falls Township	X
East Waterloo Township	X
Remainder of Black Hawk County		X
Mason City—A portion of Cerro Gordo County contained entirely within sections 27, 28, 29, 32, 33, 34 and 35 of T97N R20W and sections 2, 3, 4 and 5 of T96N R20W	X
Mason City—two separate portions of Cerro Gordo County contained entirely within sections 13, 24 and 25 of T97N R21W; sections 18, 19, 20, 21, 30, 31 and 35 of T97N R20W; and sections 1, 2, 3, 4, 5, 8, 9, 10, 11, 12, 15, 16 and 17 of T96N R20W	X
Falls Township	X
Lake Township	X
Lincoln Township	X
Remainder of Cerro Gordo County		X
An area around downtown Clinton	X
Comanche Township	X
Remainder of Clinton County		X
Burlington Township	X
Remainder of Des Moines County		X
Iowa City Township	X
Remainder of Johnson County		X
An area in and near Keokuk	X
Jackson Township	X
Jefferson Township	X
Madison Township	X
Remainder of Lee County		X
Cedar Rapids—a portion of Linn County contained entirely within T 82 N., R 7 W.; and T 83 N., R 7 W	X
Bertram Township	X
Clinton Township	X
College Township	X
Fairfax Township	X
Marion Township	X
Monroe Township	X
Putnam Township	X
Remainder of Linn County		X
The central portion of Marshalltown	X
Remainder of Marshall County		X
The central and southern portions of Muscatine	X
Fruitland Township	X
Sweetland Township	X
Montpelier Township	X
Remainder of Muscatine County		X
An area of central Des Moines east of U.S. Highway 65 & 69 (E. 14th Street)	X
Portions of Polk County contained entirely within T 78 N. R 23 W.; T 78 N. R 24 W.; T 78 N. R 25 W.; T 80 R 24 W.; T 79 N. R 23 W.; T 79 N. R 24 W.; and T 79 R 25 W	X
Clay Township	X
Douglas Township	X
Jefferson Township	X
Remainder of Polk County		X
The western portion of Council Bluffs and Carter Lake	X
Lake Township	X
Lewis Township	X
Remainder of Pottawatomie County		X
Portions of Buffalo, Davenport, Bettendorf and Riverdale	X
Remainder of Scott County		X
Center Township	X
Remainder of Wapello County		X
The central portion Ft. Dodge	X
Otho Township	X
Remainder of Webster County		X
The central and southern portions of Sioux City	X
Liberty Township	X
Woodbury Township	X
Remainder of Woodbury County		X
Remainder of State		X

¹ EPA designation replaces State designation.

Iowa—1971 Sulfur Dioxide NAAQS

[Primary and Secondary]

Designated area	Does not meet primary standards	Does not meet secondary standards	Cannot be classified	Better than national standards
Entire state				X

Iowa—2010 Sulfur Dioxide NAAQS

[Primary]

Designated area ¹	Designation
Designated area ¹	Date ²	Type
Muscatine, IA	11/18/2025	Attainment.
Muscatine County (part)
Sections 1-3, 10-15, 22-27, 34-36 of T77N, R3W (Lake Township)
Sections 1-3, 10-15, 22-27, 34-36 of T76N, R3W (Seventy-six Township)
T77N, R2W (Bloomington Township)
T76N, R2W (Fruitland Township)
All sections except 1, 12, 13, 24, 25, 36 of T77N, R1W (Sweetland Township)
Linn County, IA		Unclassifiable.
Linn County
Woodbury County, IA	9/12/2016	Unclassifiable.
Woodbury County
Des Moines County, IA	9/12/2016	Attainment/Unclassifiable.
Des Moines County
Louisa County, IA		Attainment/Unclassifiable.
Louisa County
Pottawattamie County, IA		Attainment/Unclassifiable.
Pottawattamie County
Wapello County, IA	9/12/2016	Attainment/Unclassifiable.
Wapello County
Statewide:		Attainment/Unclassifiable.
Adair County
Adams County
Allamakee County
Appanoose County
Audubon County
Benton County
Black Hawk County
Boone County
Bremer County
Buchanan County
Buena Vista County
Butler County
Calhoun County
Carroll County
Cass County
Cedar County
Cerro Gordo County
Cherokee County
Chickasaw County
Clarke County
Clay County
Clayton County
Clinton County
Crawford County
Dallas County
Davis County
Decatur County
Delaware County
Dickinson County
Dubuque County
Emmet County
Fayette County
Floyd County
Franklin County
Fremont County
Greene County
Grundy County
Guthrie County
Hamilton County
Hancock County
Hardin County
Harrison County
Henry County
Howard County
Humboldt County
Ida County
Iowa County
Jackson County
Jasper County
Jefferson County
Johnson County
Jones County
Keokuk County
Kossuth County
Lee County
Lucas County
Lyon County
Madison County
Mahaska County
Marion County
Marshall County
Mills County
Mitchell County
Monona County
Monroe County
Montgomery County
Muscatine County (portion of Muscatine County not designated Nonattainment on 10/4/2013)
O'Brien County
Osceola County
Page County
Palo Alto County
Plymouth County
Pocahontas County
Polk County
Poweshiek County
Ringgold County
Sac County
Scott County
Shelby County
Sioux County
Story County
Tama County
Taylor County
Union County
Van Buren County
Warren County
Washington County
Wayne County
Webster County
Winnebago County
Winneshiek County
Worth County
Wright County

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.

Iowa—Carbon Monoxide

Designated Area	Designation		Classification
Designated Area	Date ¹	Type	Date ¹	Type
Statewide		Unclassifiable/Attainment
Adair County
Adams County
Allamakee County
Appanoose County
Audubon County
Benton County
Black Hawk County
Boone County
Bremer County
Buchanan County
Buena Vista County
Butler County
Calhoun County
Carroll County
Cass County
Cedar County
Cerro Gordo County
Cherokee County
Chickasaw County
Clarke County
Clay County
Clayton County
Clinton County
Crawford County
Dallas County
Davis County
Decatur County
Delaware County
Des Moines County
Dickinson County
Dubuque County
Emmet County
Fayette County
Floyd County
Franklin County
Fremont County
Greene County
Grundy County
Guthrie County
Hamilton County
Hancock County
Hardin County
Harrison County
Henry County
Howard County
Humboldt County
Ida County
Iowa County
Jackson County
Jasper County
Jefferson County
Johnson County
Jones County
Keokuk County
Kossuth County
Lee County
Linn County
Louisa County
Lucas County
Lyon County
Madison County
Mahaska County
Marion County
Marshall County
Mills County
Mitchell County
Monona County
Monroe County
Montgomery County
Muscatine County
O'Brien County
Osceola County
Page County
Palo Alto County
Plymouth County
Pocahontas County
Polk County
Pottawattamie County
Poweshiek County
Ringgold County
Sac County
Scott County
Shelby County
Sioux County
Story County
Tama County
Taylor County
Union County
Van Buren County
Wapello County
Warren County
Washington County
Wayne County
Webster County
Winnebago County
Winneshiek County
Woodbury County
Worth County
Wright County

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

Iowa—Ozone (1-Hour Standard) ²

Designated area	Designation		Classification
Designated area	Date ¹	Type	Date ¹	Type
Statewide		Unclassifiable/Attainment
Adair County
Adams County
Allamakee County
Appanoose County
Audubon County
Benton County
Black Hawk County
Boone County
Bremer County
Buchanan County
Buena Vista County
Butler County
Calhoun County
Carroll County
Cass County
Cedar County
Cerro Gordo County
Cherokee County
Chickasaw County
Clarke County
Clay County
Clayton County
Clinton County
Crawford County
Dallas County
Davis County
Decatur County
Delaware County
Des Moines County
Dickinson County
Dubuque County
Emmet County
Fayette County
Floyd County
Franklin County
Fremont County
Greene County
Grundy County
Guthrie County
Hamilton County
Hancock County
Hardin County
Harrison County
Henry County
Howard County
Humboldt County
Ida County
Iowa County
Jackson County
Jasper County
Jefferson County
Johnson County
Jones County
Keokuk County
Kossuth County
Lee County
Linn County
Louisa County
Lucas County
Lyon County
Madison County
Mahaska County
Marion County
Marshall County
Mills County
Mitchell County
Monona County
Monroe County
Montgomery County
Muscatine County
O'Brien County
Osceola County
Page County
Palo Alto County
Plymouth County
Pocahontas County
Polk County
Pottawattamie County
Poweshiek County
Ringgold County
Sac County
Scott County
Shelby County
Sioux County
Story County
Tama County
Taylor County
Union County
Van Buren County
Wapello County
Warren County
Washington County
Wayne County
Webster County
Winnebago County
Winneshiek County
Woodbury County
Worth County
Wright County

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 Iowa.

Iowa—1997 Annual PM2.5 NAAQS

[Primary and Secondary]

Designated area	Designation ^a		Classification
Designated area	Date ¹	Type	Date	Type
Statewide:
Adair County		Unclassifiable/Attainment.
Adams County		Unclassifiable/Attainment.
Allamakee County		Unclassifiable/Attainment.
Appanoose County		Unclassifiable/Attainment.
Audubon County		Unclassifiable/Attainment.
Benton County		Unclassifiable/Attainment.
Black Hawk County		Unclassifiable/Attainment.
Boone County		Unclassifiable/Attainment.
Bremer County		Unclassifiable/Attainment.
Buchanan County		Unclassifiable/Attainment.
Buena Vista County		Unclassifiable/Attainment.
Butler County		Unclassifiable/Attainment.
Calhoun County		Unclassifiable/Attainment.
Carroll County		Unclassifiable/Attainment.
Cass County		Unclassifiable/Attainment.
Cedar County		Unclassifiable/Attainment.
Cerro Gordo County		Unclassifiable/Attainment.
Cherokee County		Unclassifiable/Attainment.
Chickasaw County		Unclassifiable/Attainment.
Clarke County		Unclassifiable/Attainment.
Clay County		Unclassifiable/Attainment.
Clayton County		Unclassifiable/Attainment.
Clinton County		Unclassifiable/Attainment.
Crawford County		Unclassifiable/Attainment.
Dallas County		Unclassifiable/Attainment.
Davis County		Unclassifiable/Attainment.
Decatur County		Unclassifiable/Attainment.
Delaware County		Unclassifiable/Attainment.
Des Moines County		Unclassifiable/Attainment.
Dickinson County		Unclassifiable/Attainment.
Dubuque County		Unclassifiable/Attainment.
Emmet County		Unclassifiable/Attainment.
Fayette County		Unclassifiable/Attainment.
Floyd County		Unclassifiable/Attainment.
Franklin County		Unclassifiable/Attainment.
Fremont County		Unclassifiable/Attainment.
Greene County		Unclassifiable/Attainment.
Grundy County		Unclassifiable/Attainment.
Guthrie County		Unclassifiable/Attainment.
Hamilton County		Unclassifiable/Attainment.
Hancock County		Unclassifiable/Attainment.
Hardin County		Unclassifiable/Attainment.
Harrison County		Unclassifiable/Attainment.
Henry County		Unclassifiable/Attainment.
Howard County		Unclassifiable/Attainment.
Humboldt County		Unclassifiable/Attainment.
Ida County		Unclassifiable/Attainment.
Iowa County		Unclassifiable/Attainment.
Jackson County		Unclassifiable/Attainment.
Jasper County		Unclassifiable/Attainment.
Jefferson County		Unclassifiable/Attainment.
Johnson County		Unclassifiable/Attainment.
Jones County		Unclassifiable/Attainment.
Keokuk County		Unclassifiable/Attainment.
Kossuth County		Unclassifiable/Attainment.
Lee County		Unclassifiable/Attainment.
Linn County		Unclassifiable/Attainment.
Louisa County		Unclassifiable/Attainment.
Lucas County		Unclassifiable/Attainment.
Lyon County		Unclassifiable/Attainment.
Madison County		Unclassifiable/Attainment.
Mahaska County		Unclassifiable/Attainment.
Marion County		Unclassifiable/Attainment.
Marshall County		Unclassifiable/Attainment.
Mills County		Unclassifiable/Attainment.
Mitchell County		Unclassifiable/Attainment.
Monona County		Unclassifiable/Attainment.
Monroe County		Unclassifiable/Attainment.
Montgomery County		Unclassifiable/Attainment.
Muscatine County		Unclassifiable/Attainment.
O'Brien County		Unclassifiable/Attainment.
Osceola County		Unclassifiable/Attainment.
Page County		Unclassifiable/Attainment.
Palo Alto County		Unclassifiable/Attainment.
Plymouth County		Unclassifiable/Attainment.
Pocahontas County		Unclassifiable/Attainment.
Polk County		Unclassifiable/Attainment.
Pottawattamie County		Unclassifiable/Attainment.
Poweshiek County		Unclassifiable/Attainment.
Ringgold County		Unclassifiable/Attainment.
Sac County		Unclassifiable/Attainment.
Scott County		Unclassifiable/Attainment.
Shelby County		Unclassifiable/Attainment.
Sioux County		Unclassifiable/Attainment.
Story County		Unclassifiable/Attainment.
Tama County		Unclassifiable/Attainment.
Taylor County		Unclassifiable/Attainment.
Union County		Unclassifiable/Attainment.
Van Buren County		Unclassifiable/Attainment.
Wapello County		Unclassifiable/Attainment.
Warren County		Unclassifiable/Attainment.
Washington County		Unclassifiable/Attainment.
Wayne County		Unclassifiable/Attainment.
Webster County		Unclassifiable/Attainment.
Winnebago County		Unclassifiable/Attainment.
Winneshiek County		Unclassifiable/Attainment.
Woodbury County		Unclassifiable/Attainment.
Worth County		Unclassifiable/Attainment.
Wright County		Unclassifiable/Attainment.

^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.

Iowa—2012 Annual PM2.5 NAAQS

[Primary]

Designated area ¹	Designation		Classification
Designated area ¹	Date ²	Type	Date ²	Type
Statewide:
Adair County		Unclassifiable/Attainment
Adams County		Unclassifiable/Attainment
Allamakee County		Unclassifiable/Attainment
Appanoose County		Unclassifiable/Attainment
Audubon County		Unclassifiable/Attainment
Benton County		Unclassifiable/Attainment
Black Hawk County		Unclassifiable/Attainment
Boone County		Unclassifiable/Attainment
Bremer County		Unclassifiable/Attainment
Buchanan County		Unclassifiable/Attainment
Buena Vista County		Unclassifiable/Attainment
Butler County		Unclassifiable/Attainment
Calhoun County		Unclassifiable/Attainment
Carroll County		Unclassifiable/Attainment
Cass County		Unclassifiable/Attainment
Cedar County		Unclassifiable/Attainment
Cerro Gordo County		Unclassifiable/Attainment
Cherokee County		Unclassifiable/Attainment
Chickasaw County		Unclassifiable/Attainment
Clarke County		Unclassifiable/Attainment
Clay County		Unclassifiable/Attainment
Clayton County		Unclassifiable/Attainment
Clinton County		Unclassifiable/Attainment
Crawford County		Unclassifiable/Attainment
Dallas County		Unclassifiable/Attainment
Davis County		Unclassifiable/Attainment
Decatur County		Unclassifiable/Attainment
Delaware County		Unclassifiable/Attainment
Des Moines County		Unclassifiable/Attainment
Dickinson County		Unclassifiable/Attainment
Dubuque County		Unclassifiable/Attainment
Emmet County		Unclassifiable/Attainment
Fayette County		Unclassifiable/Attainment
Floyd County		Unclassifiable/Attainment
Franklin County		Unclassifiable/Attainment
Fremont County		Unclassifiable/Attainment
Greene County		Unclassifiable/Attainment
Grundy County		Unclassifiable/Attainment
Guthrie County		Unclassifiable/Attainment
Hamilton County		Unclassifiable/Attainment
Hancock County		Unclassifiable/Attainment
Hardin County		Unclassifiable/Attainment
Harrison County		Unclassifiable/Attainment
Henry County		Unclassifiable/Attainment
Howard County		Unclassifiable/Attainment
Humboldt County		Unclassifiable/Attainment
Ida County		Unclassifiable/Attainment
Iowa County		Unclassifiable/Attainment
Jackson County		Unclassifiable/Attainment
Jasper County		Unclassifiable/Attainment
Jefferson County		Unclassifiable/Attainment
Johnson County		Unclassifiable/Attainment
Jones County		Unclassifiable/Attainment
Keokuk County		Unclassifiable/Attainment
Kossuth County		Unclassifiable/Attainment
Lee County		Unclassifiable/Attainment
Linn County		Unclassifiable/Attainment
Louisa County		Unclassifiable/Attainment
Lucas County		Unclassifiable/Attainment
Lyon County		Unclassifiable/Attainment
Madison County		Unclassifiable/Attainment
Mahaska County		Unclassifiable/Attainment
Marion County		Unclassifiable/Attainment
Marshall County		Unclassifiable/Attainment
Mills County		Unclassifiable/Attainment
Mitchell County		Unclassifiable/Attainment
Monona County		Unclassifiable/Attainment
Monroe County		Unclassifiable/Attainment
Montgomery County		Unclassifiable/Attainment
Muscatine County		Unclassifiable/Attainment
O'Brien County		Unclassifiable/Attainment
Osceola County		Unclassifiable/Attainment
Page County		Unclassifiable/Attainment
Palo Alto County		Unclassifiable/Attainment
Plymouth County		Unclassifiable/Attainment
Pocahontas County		Unclassifiable/Attainment
Polk County		Unclassifiable/Attainment
Pottawattamie County		Unclassifiable/Attainment
Poweshiek County		Unclassifiable/Attainment
Ringgold County		Unclassifiable/Attainment
Sac County		Unclassifiable/Attainment
Scott County		Unclassifiable/Attainment
Shelby County		Unclassifiable/Attainment
Sioux County		Unclassifiable/Attainment
Story County		Unclassifiable/Attainment
Tama County		Unclassifiable/Attainment
Taylor County		Unclassifiable/Attainment
Union County		Unclassifiable/Attainment
Van Buren County		Unclassifiable/Attainment
Wapello County		Unclassifiable/Attainment
Warren County		Unclassifiable/Attainment
Washington County		Unclassifiable/Attainment
Wayne County		Unclassifiable/Attainment
Webster County		Unclassifiable/Attainment
Winnebago County		Unclassifiable/Attainment
Winneshiek County		Unclassifiable/Attainment
Woodbury County		Unclassifiable/Attainment
Worth County		Unclassifiable/Attainment
Wright County		Unclassifiable/Attainment

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.

Iowa—1997 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated area	Designation ^a		Classification
Designated area	Date ¹	Type	Date	Type
Statewide:
Adair County		Unclassifiable/Attainment
Adams County		Unclassifiable/Attainment
Allamakee County		Unclassifiable/Attainment
Appanoose County		Unclassifiable/Attainment
Audubon County		Unclassifiable/Attainment
Benton County		Unclassifiable/Attainment
Black Hawk County		Unclassifiable/Attainment
Boone County		Unclassifiable/Attainment
Bremer County		Unclassifiable/Attainment
Buchanan County		Unclassifiable/Attainment
Buena Vista County		Unclassifiable/Attainment
Butler County		Unclassifiable/Attainment
Calhoun County		Unclassifiable/Attainment
Carroll County		Unclassifiable/Attainment
Cass County		Unclassifiable/Attainment
Cedar County		Unclassifiable/Attainment
Cerro Gordo County		Unclassifiable/Attainment
Cherokee County		Unclassifiable/Attainment
Chickasaw County		Unclassifiable/Attainment
Clarke County		Unclassifiable/Attainment
Clay County		Unclassifiable/Attainment
Clayton County		Unclassifiable/Attainment
Clinton County		Unclassifiable/Attainment
Crawford County		Unclassifiable/Attainment
Dallas County		Unclassifiable/Attainment
Davis County		Unclassifiable/Attainment
Decatur County		Unclassifiable/Attainment
Delaware County		Unclassifiable/Attainment
Des Moines County		Unclassifiable/Attainment
Dickinson County		Unclassifiable/Attainment
Dubuque County		Unclassifiable/Attainment
Emmet County		Unclassifiable/Attainment
Fayette County		Unclassifiable/Attainment
Floyd County		Unclassifiable/Attainment
Franklin County		Unclassifiable/Attainment
Fremont County		Unclassifiable/Attainment
Greene County		Unclassifiable/Attainment
Grundy County		Unclassifiable/Attainment
Guthrie County		Unclassifiable/Attainment
Hamilton County		Unclassifiable/Attainment
Hancock County		Unclassifiable/Attainment
Hardin County		Unclassifiable/Attainment
Harrison County		Unclassifiable/Attainment
Henry County		Unclassifiable/Attainment
Howard County		Unclassifiable/Attainment
Humboldt County		Unclassifiable/Attainment
Ida County		Unclassifiable/Attainment
Iowa County		Unclassifiable/Attainment
Jackson County		Unclassifiable/Attainment
Jasper County		Unclassifiable/Attainment
Jefferson County		Unclassifiable/Attainment
Johnson County		Unclassifiable/Attainment
Jones County		Unclassifiable/Attainment
Keokuk County		Unclassifiable/Attainment
Kossuth County		Unclassifiable/Attainment
Lee County		Unclassifiable/Attainment
Linn County		Unclassifiable/Attainment
Louisa County		Unclassifiable/Attainment
Lucas County		Unclassifiable/Attainment
Lyon County		Unclassifiable/Attainment
Madison County		Unclassifiable/Attainment
Mahaska County		Unclassifiable/Attainment
Marion County		Unclassifiable/Attainment
Marshall County		Unclassifiable/Attainment
Mills County		Unclassifiable/Attainment
Mitchell County		Unclassifiable/Attainment
Monona County		Unclassifiable/Attainment
Monroe County		Unclassifiable/Attainment
Montgomery County		Unclassifiable/Attainment
Muscatine County		Unclassifiable/Attainment
O'Brien County		Unclassifiable/Attainment
Osceola County		Unclassifiable/Attainment
Page County		Unclassifiable/Attainment
Palo Alto County		Unclassifiable/Attainment
Plymouth County		Unclassifiable/Attainment
Pocahontas County		Unclassifiable/Attainment
Polk County		Unclassifiable/Attainment
Pottawattamie County		Unclassifiable/Attainment
Poweshiek County		Unclassifiable/Attainment
Ringgold County		Unclassifiable/Attainment
Sac County		Unclassifiable/Attainment
Scott County		Unclassifiable/Attainment
Shelby County		Unclassifiable/Attainment
Sioux County		Unclassifiable/Attainment
Story County		Unclassifiable/Attainment
Tama County		Unclassifiable/Attainment
Taylor County		Unclassifiable/Attainment
Union County		Unclassifiable/Attainment
Van Buren County		Unclassifiable/Attainment
Wapello County		Unclassifiable/Attainment
Warren County		Unclassifiable/Attainment
Washington County		Unclassifiable/Attainment
Wayne County		Unclassifiable/Attainment
Webster County		Unclassifiable/Attainment
Winnebago County		Unclassifiable/Attainment
Winneshiek County		Unclassifiable/Attainment
Woodbury County		Unclassifiable/Attainment
Worth County		Unclassifiable/Attainment
Wright County		Unclassifiable/Attainment

^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.

Iowa—2006 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated area	Designation ^a		Classification
Designated area	Date ¹	Type	Date	Type
Statewide:
Adair County		Unclassifiable/Attainment
Adams County		Unclassifiable/Attainment
Allamakee County		Unclassifiable/Attainment
Appanoose County		Unclassifiable/Attainment
Audubon County		Unclassifiable/Attainment
Benton County		Unclassifiable/Attainment
Black Hawk County		Unclassifiable/Attainment
Boone County		Unclassifiable/Attainment
Bremer County		Unclassifiable/Attainment
Buchanan County		Unclassifiable/Attainment
Buena Vista County		Unclassifiable/Attainment
Butler County		Unclassifiable/Attainment
Calhoun County		Unclassifiable/Attainment
Carroll County		Unclassifiable/Attainment
Cass County		Unclassifiable/Attainment
Cedar County		Unclassifiable/Attainment
Cerro Gordo County		Unclassifiable/Attainment
Cherokee County		Unclassifiable/Attainment
Chickasaw County		Unclassifiable/Attainment
Clarke County		Unclassifiable/Attainment
Clay County		Unclassifiable/Attainment
Clayton County		Unclassifiable/Attainment
Clinton County		Unclassifiable/Attainment
Crawford County		Unclassifiable/Attainment
Dallas County		Unclassifiable/Attainment
Davis County		Unclassifiable/Attainment
Decatur County		Unclassifiable/Attainment
Delaware County		Unclassifiable/Attainment
Des Moines County		Unclassifiable/Attainment
Dickinson County		Unclassifiable/Attainment
Dubuque County		Unclassifiable/Attainment
Emmet County		Unclassifiable/Attainment
Fayette County		Unclassifiable/Attainment
Floyd County		Unclassifiable/Attainment
Franklin County		Unclassifiable/Attainment
Fremont County		Unclassifiable/Attainment
Greene County		Unclassifiable/Attainment
Grundy County		Unclassifiable/Attainment
Guthrie County		Unclassifiable/Attainment
Hamilton County		Unclassifiable/Attainment
Hancock County		Unclassifiable/Attainment
Hardin County		Unclassifiable/Attainment
Harrison County		Unclassifiable/Attainment
Henry County		Unclassifiable/Attainment
Howard County		Unclassifiable/Attainment
Humboldt County		Unclassifiable/Attainment
Ida County		Unclassifiable/Attainment
Iowa County		Unclassifiable/Attainment
Jackson County		Unclassifiable/Attainment
Jasper County		Unclassifiable/Attainment
Jefferson County		Unclassifiable/Attainment
Johnson County		Unclassifiable/Attainment
Jones County		Unclassifiable/Attainment
Keokuk County		Unclassifiable/Attainment
Kossuth County		Unclassifiable/Attainment
Lee County		Unclassifiable/Attainment
Linn County		Unclassifiable/Attainment
Louisa County		Unclassifiable/Attainment
Lucas County		Unclassifiable/Attainment
Lyon County		Unclassifiable/Attainment
Madison County		Unclassifiable/Attainment
Mahaska County		Unclassifiable/Attainment
Marion County		Unclassifiable/Attainment
Marshall County		Unclassifiable/Attainment
Mills County		Unclassifiable/Attainment
Mitchell County		Unclassifiable/Attainment
Monona County		Unclassifiable/Attainment
Monroe County		Unclassifiable/Attainment
Montgomery County		Unclassifiable/Attainment
Muscatine County		Unclassifiable/Attainment
O'Brien County		Unclassifiable/Attainment
Osceola County		Unclassifiable/Attainment
Page County		Unclassifiable/Attainment
Palo Alto County		Unclassifiable/Attainment
Plymouth County		Unclassifiable/Attainment
Pocahontas County		Unclassifiable/Attainment
Polk County		Unclassifiable/Attainment
Pottawattamie County		Unclassifiable/Attainment
Poweshiek County		Unclassifiable/Attainment
Ringgold County		Unclassifiable/Attainment
Sac County		Unclassifiable/Attainment
Scott County		Unclassifiable/Attainment
Shelby County		Unclassifiable/Attainment
Sioux County		Unclassifiable/Attainment
Story County		Unclassifiable/Attainment
Tama County		Unclassifiable/Attainment
Taylor County		Unclassifiable/Attainment
Union County		Unclassifiable/Attainment
Van Buren County		Unclassifiable/Attainment
Wapello County		Unclassifiable/Attainment
Warren County		Unclassifiable/Attainment
Washington County		Unclassifiable/Attainment
Wayne County		Unclassifiable/Attainment
Webster County		Unclassifiable/Attainment
Winnebago County		Unclassifiable/Attainment
Winneshiek County		Unclassifiable/Attainment
Woodbury County		Unclassifiable/Attainment
Worth County		Unclassifiable/Attainment
Wright County		Unclassifiable/Attainment

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

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

Iowa—NO2 (1971 Annual Standard)

Designated area	Does not meet primary standards	Cannot be classified or better than national standards
Entire State		X

Iowa—NO2 (2010 1-Hour Standard)

Designated area	Designation ^a
Designated area	Date ¹	Type
Adair County		Unclassifiable/Attainment.
Adams County		Unclassifiable/Attainment.
Allamakee County		Unclassifiable/Attainment.
Appanoose County		Unclassifiable/Attainment.
Audubon County		Unclassifiable/Attainment.
Benton County		Unclassifiable/Attainment.
Black Hawk County		Unclassifiable/Attainment.
Boone County		Unclassifiable/Attainment.
Bremer County		Unclassifiable/Attainment.
Buchanan County		Unclassifiable/Attainment.
Buena Vista County		Unclassifiable/Attainment.
Butler County		Unclassifiable/Attainment.
Calhoun County		Unclassifiable/Attainment.
Carroll County		Unclassifiable/Attainment.
Cass County		Unclassifiable/Attainment.
Cedar County		Unclassifiable/Attainment.
Cerro Gordo County		Unclassifiable/Attainment.
Cherokee County		Unclassifiable/Attainment.
Chickasaw County		Unclassifiable/Attainment.
Clarke County		Unclassifiable/Attainment.
Clay County		Unclassifiable/Attainment.
Clayton County		Unclassifiable/Attainment.
Clinton County		Unclassifiable/Attainment.
Crawford County		Unclassifiable/Attainment.
Dallas County		Unclassifiable/Attainment.
Davis County		Unclassifiable/Attainment.
Decatur County		Unclassifiable/Attainment.
Delaware County		Unclassifiable/Attainment.
Des Moines County		Unclassifiable/Attainment.
Dickinson County		Unclassifiable/Attainment.
Dubuque County		Unclassifiable/Attainment.
Emmet County		Unclassifiable/Attainment.
Fayette County		Unclassifiable/Attainment.
Floyd County		Unclassifiable/Attainment.
Franklin County		Unclassifiable/Attainment.
Fremont County		Unclassifiable/Attainment.
Greene County		Unclassifiable/Attainment.
Grundy County		Unclassifiable/Attainment.
Guthrie County		Unclassifiable/Attainment.
Hamilton County		Unclassifiable/Attainment.
Hancock County		Unclassifiable/Attainment.
Hardin County		Unclassifiable/Attainment.
Harrison County		Unclassifiable/Attainment.
Henry County		Unclassifiable/Attainment.
Howard County		Unclassifiable/Attainment.
Humboldt County		Unclassifiable/Attainment.
Ida County		Unclassifiable/Attainment.
Iowa County		Unclassifiable/Attainment.
Jackson County		Unclassifiable/Attainment.
Jasper County		Unclassifiable/Attainment.
Jefferson County		Unclassifiable/Attainment.
Johnson County		Unclassifiable/Attainment.
Jones County		Unclassifiable/Attainment.
Keokuk County		Unclassifiable/Attainment.
Kossuth County		Unclassifiable/Attainment.
Lee County		Unclassifiable/Attainment.
Linn County		Unclassifiable/Attainment.
Louisa County		Unclassifiable/Attainment.
Lucas County		Unclassifiable/Attainment.
Lyon County		Unclassifiable/Attainment.
Madison County		Unclassifiable/Attainment.
Mahaska County		Unclassifiable/Attainment.
Marion County		Unclassifiable/Attainment.
Marshall County		Unclassifiable/Attainment.
Mills County		Unclassifiable/Attainment.
Mitchell County		Unclassifiable/Attainment.
Monona County		Unclassifiable/Attainment.
Monroe County		Unclassifiable/Attainment.
Montgomery County		Unclassifiable/Attainment.
Muscatine County		Unclassifiable/Attainment.
O'Brien County		Unclassifiable/Attainment.
Osceola County		Unclassifiable/Attainment.
Page County		Unclassifiable/Attainment.
Palo Alto County		Unclassifiable/Attainment.
Plymouth County		Unclassifiable/Attainment.
Pocahontas County		Unclassifiable/Attainment.
Polk County		Unclassifiable/Attainment.
Pottawattamie County		Unclassifiable/Attainment.
Poweshiek County		Unclassifiable/Attainment.
Ringgold County		Unclassifiable/Attainment.
Sac County		Unclassifiable/Attainment.
Scott County		Unclassifiable/Attainment.
Shelby County		Unclassifiable/Attainment.
Sioux County		Unclassifiable/Attainment.
Story County		Unclassifiable/Attainment.
Tama County		Unclassifiable/Attainment.
Taylor County		Unclassifiable/Attainment.
Union County		Unclassifiable/Attainment.
Van Buren County		Unclassifiable/Attainment.
Wapello County		Unclassifiable/Attainment.
Warren County		Unclassifiable/Attainment.
Washington County		Unclassifiable/Attainment.
Wayne County		Unclassifiable/Attainment.
Webster County		Unclassifiable/Attainment.
Winnebago County		Unclassifiable/Attainment.
Winneshiek County		Unclassifiable/Attainment.
Woodbury County		Unclassifiable/Attainment.
Worth County		Unclassifiable/Attainment.
Wright County		Unclassifiable/Attainment.

^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.

Iowa—1997 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area	Designation ^a		Category/classification
Designated area	Date ¹	Type	Date ¹	Type
Statewide		Unclassifiable/Attainment
Adair County
Adams County
Allamakee County
Appanoose County
Audubon County
Benton County
Black Hawk County
Boone County
Bremer County
Buchanan County
Buena Vista County
Butler County
Calhoun County
Carroll County
Cass County
Cedar County
Cerro Gordo County
Cherokee County
Chickasaw County
Clarke County
Clay County
Clayton County
Clinton County
Crawford County
Dallas County
Davis County
Decatur County
Delaware County
Des Moines County
Dickinson County
Dubuque County
Emmet County
Fayette County
Floyd County
Franklin County
Fremont County
Greene County
Grundy County
Guthrie County
Hamilton County
Hancock County
Hardin County
Harrison County
Henry County
Howard County
Humboldt County
Ida County
Iowa County
Jackson County
Jasper County
Jefferson County
Johnson County
Jones County
Keokuk County
Kossuth County
Lee County
Linn County
Louisa County
Lucas County
Lyon County
Madison County
Mahaska County
Marion County
Marshall County
Mills County
Mitchell County
Monona County
Monroe County
Montgomery County
Muscatine County
O'Brien County
Osceola County
Page County
Palo Alto County
Plymouth County
Pocahontas County
Polk County
Pottawattamie County
Poweshiek County
Ringgold County
Sac County
Scott County
Shelby County
Sioux County
Story County
Tama County
Taylor County
Union County
Van Buren County
Wapello County
Warren County
Washington County
Wayne County
Webster County
Winnebago County
Winneshiek County
Woodbury County
Worth County
Wright County

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

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

Iowa—2008 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area	Designation		Classification
Designated area	Date ¹	Type	Date ¹	Type
Statewide and Any Areas of Indian Country:		Unclassifiable/Attainment
Adair County
Adams County
Allamakee County
Appanoose County
Audubon County
Benton County
Black Hawk County
Boone County
Bremer County
Buchanan County
Buena Vista County
Butler County
Calhoun County
Carroll County
Cass County
Cedar County
Cerro Gordo County
Cherokee County
Chickasaw County
Clarke County
Clay County
Clayton County
Clinton County
Crawford County
Dallas County
Davis County
Decatur County
Delaware County
Des Moines County
Dickinson County
Dubuque County
Emmet County
Fayette County
Floyd County
Franklin County
Fremont County
Greene County
Grundy County
Guthrie County
Hamilton County
Hancock County
Hardin County
Harrison County
Henry County
Howard County
Humboldt County
Ida County
Iowa County
Jackson County
Jasper County
Jefferson County
Johnson County
Jones County
Keokuk County
Kossuth County
Lee County
Linn County
Louisa County
Lucas County
Lyon County
Madison County
Mahaska County
Marion County
Marshall County
Mills County
Mitchell County
Monona County
Monroe County
Montgomery County
Muscatine County
O'Brien County
Osceola County
Page County
Palo Alto County
Plymouth County
Pocahontas County
Polk County
Pottawattamie County
Poweshiek County
Ringgold County
Sac County
Scott County
Shelby County
Sioux County
Story County
Tama County
Taylor County
Union County
Van Buren County
Wapello County
Warren County
Washington County
Wayne County
Webster County
Winnebago County
Winneshiek County
Woodbury County
Worth County
Wright County

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

Iowa—2015 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area ¹	Designation		Classification
Designated area ¹	Date ²	Type	Date	Type
Statewide		Attainment/Unclassifiable
Adair County.
Adams County.
Allamakee County.
Appanoose County.
Audubon County.
Benton County.
Black Hawk County.
Boone County.
Bremer County.
Buchanan County.
Buena Vista County.
Butler County.
Calhoun County.
Carroll County.
Cass County.
Cedar County.
Cerro Gordo County.
Cherokee County.
Chickasaw County.
Clarke County.
Clay County.
Clayton County.
Clinton County.
Crawford County.
Dallas County.
Davis County.
Decatur County.
Delaware County.
Des Moines County.
Dickinson County.
Dubuque County.
Emmet County.
Fayette County.
Floyd County.
Franklin County.
Fremont County.
Greene County.
Grundy County.
Guthrie County.
Hamilton County.
Hancock County.
Hardin County.
Harrison County.
Henry County.
Howard County.
Humboldt County.
Ida County.
Iowa County.
Jackson County.
Jasper County.
Jefferson County.
Johnson County.
Jones County.
Keokuk County.
Kossuth County.
Lee County.
Linn County.
Louisa County.
Lucas County.
Lyon County.
Madison County.
Mahaska County.
Marion County.
Marshall County.
Mills County.
Mitchell County.
Monona County.
Monroe County.
Montgomery County.
Muscatine County.
O'Brien County.
Osceola County.
Page County.
Palo Alto County.
Plymouth County.
Pocahontas County.
Polk County.
Pottawattamie County.
Poweshiek County.
Ringgold County.
Sac County.
Scott County.
Shelby County.
Sioux County.
Story County.
Tama County.
Taylor County.
Union County.
Van Buren County.
Wapello County.
Warren County.
Washington County.
Wayne County.
Webster County.
Winnebago County.
Winneshiek County.
Woodbury County.
Worth County.
Wright County.	.

² This date is January 16, 2018, unless otherwise noted.

Iowa—2008 Lead NAAQS

Designated area	Designation for the 2008 NAAQS ^a
Designated area	Date ¹	Type
Pottawattamie County, IA:
Pottawattamie County (part)	10/4/2018	Attainment.
Area bounded by Avenue G on the north, N 16th/S 16th street on the east, 23rd Avenue on the south, and N 35th/S 35th street on the west
Rest of State		Unclassifiable/Attainment.

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

¹ December 31, 2011 unless otherwise noted.

[43 FR 8964, Mar. 3, 1978] Editorial Note:For Federal Register citations affecting § 81.316, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

authority: 42 U.S.C. 7401,

source: 36 FR 22421, Nov. 25, 1971, unless otherwise noted.

cite as: 40 CFR 81.316