Cities Where Air Quality Is Getting Worse

These cities show a rising AQI trend over the past decade, meaning air pollution is increasing year over year.

244

Worsening Cities

Avg AQI (5yr)

23.9%

Of All Cities

All Worsening Cities

City	State	5yr Avg AQI	Grade	Trend	Worst Pollutant
Harrison, Ohio	OH	10	B	+6.3/yr	CO
Delta, Colorado	CO	42	C	+4.1/yr	Ozone
Johnson, Wyoming	WY	40	C	+4.0/yr	Ozone
Lincoln, Wyoming	WY	29	C	+3.4/yr	PM10
Catano, Puerto Rico	PR	42	D	+3.3/yr	PM2.5
Archuleta, Colorado	CO	39	C	+3.0/yr	Ozone
Sanders, Montana	MT	36	D	+3.0/yr	PM2.5
Maricopa, Arizona	AZ	90	F	+2.9/yr	Ozone
Valley, Idaho	ID	37	D	+2.8/yr	PM2.5
SONORA, Country Of Mexico	MX	44	D	+2.3/yr	Ozone
Cass, Minnesota	MN	32	C	+2.3/yr	PM2.5
Grant, Oklahoma	OK	28	C	+2.2/yr	PM2.5
Columbia, Washington	WA	32	C	+2.2/yr	PM2.5
Douglas, Oregon	OR	36	C	+2.1/yr	PM2.5
Winnebago, Illinois	IL	48	D	+1.9/yr	Ozone
Codington, South Dakota	SD	40	D	+1.9/yr	PM2.5
Mono, California	CA	33	D	+1.9/yr	PM2.5
Rock Island, Illinois	IL	47	D	+1.9/yr	PM2.5
Neosho, Kansas	KS	48	D	+1.8/yr	Ozone
Horry, South Carolina	SC	37	C	+1.8/yr	Ozone
Jackson, Mississippi	MS	46	D	+1.8/yr	PM2.5
Bonner, Idaho	ID	33	C	+1.8/yr	PM2.5
Culberson, Texas	TX	37	C	+1.7/yr	PM2.5
Inyo, California	CA	57	F	+1.7/yr	Ozone
Asotin, Washington	WA	43	D	+1.6/yr	PM2.5
Del Norte, California	CA	32	C	+1.6/yr	PM2.5
Sangamon, Illinois	IL	46	D	+1.6/yr	PM2.5
Sumner, Kansas	KS	47	C	+1.6/yr	Ozone
Canyon, Idaho	ID	41	C	+1.6/yr	PM2.5
BAJA CALIFORNIA NORTE, Country Of Mexico	MX	81	F	+1.6/yr	PM2.5
Henderson, Kentucky	KY	53	D	+1.5/yr	PM2.5
Scioto, Ohio	OH	21	C	+1.5/yr	PM10
York, South Carolina	SC	44	C	+1.4/yr	Ozone
Guaynabo, Puerto Rico	PR	29	C	+1.4/yr	NO2
Bolivar, Mississippi	MS	47	C	+1.4/yr	PM2.5
Baker, Florida	FL	40	C	+1.4/yr	Ozone
McLean, Illinois	IL	48	D	+1.4/yr	PM2.5
Scott, Minnesota	MN	41	C	+1.4/yr	Ozone
Blaine, Idaho	ID	21	C	+1.4/yr	PM2.5
Butler, Ohio	OH	50	D	+1.4/yr	Ozone
Harney, Oregon	OR	44	C	+1.3/yr	PM2.5
Johnson, Kansas	KS	44	C	+1.3/yr	Ozone
Lafourche, Louisiana	LA	48	C	+1.3/yr	PM2.5
Ward, North Dakota	ND	36	C	+1.3/yr	Ozone
Bernalillo, New Mexico	NM	59	D	+1.3/yr	Ozone
DuPage, Illinois	IL	49	D	+1.3/yr	PM2.5
Chaffee, Colorado	CO	53	C	+1.2/yr	Ozone
Hancock, Mississippi	MS	45	C	+1.2/yr	PM2.5
Kane, Illinois	IL	43	C	+1.2/yr	Ozone
Madison, Alabama	AL	48	C	+1.2/yr	PM2.5
Siskiyou, California	CA	41	D	+1.2/yr	Ozone
Franklin, New York	NY	31	C	+1.2/yr	Ozone
Shawnee, Kansas	KS	46	C	+1.1/yr	PM2.5
Idaho, Idaho	ID	42	C	+1.1/yr	PM2.5
Becker, Minnesota	MN	39	C	+1.1/yr	PM2.5
Bell, Kentucky	KY	45	C	+1.1/yr	Ozone
Citrus, Florida	FL	43	C	+1.1/yr	PM2.5
McClain, Oklahoma	OK	44	C	+1.0/yr	Ozone
Elko, Nevada	NV	31	C	+1.0/yr	PM10
Bell, Texas	TX	45	C	+1.0/yr	Ozone
Trinity, California	CA	32	C	+1.0/yr	PM2.5
Bannock, Idaho	ID	37	C	+1.0/yr	PM2.5
Grant, Oregon	OR	45	C	+1.0/yr	PM2.5
Wright, Minnesota	MN	41	C	+1.0/yr	PM2.5
Mayagnez, Puerto Rico	PR	31	C	+0.9/yr	PM2.5
Missaukee, Michigan	MI	43	C	+0.9/yr	Ozone
Richmond City, Virginia	VA	42	C	+0.9/yr	PM2.5
Broward, Florida	FL	49	C	+0.9/yr	PM2.5
Columbia, Florida	FL	45	C	+0.9/yr	PM2.5
Lake, Illinois	IL	40	C	+0.9/yr	Ozone
Lycoming, Pennsylvania	PA	40	C	+0.9/yr	Ozone
Lyon, Minnesota	MN	38	C	+0.9/yr	PM2.5
Boulder, Colorado	CO	50	D	+0.9/yr	Ozone
Dakota, Minnesota	MN	40	C	+0.9/yr	PM2.5
Mendocino, California	CA	46	C	+0.9/yr	PM2.5
El Paso, Texas	TX	60	D	+0.9/yr	PM2.5
Latah, Idaho	ID	18	B	+0.9/yr	PM2.5
Nez Perce, Idaho	ID	33	C	+0.9/yr	PM2.5
Stearns, Minnesota	MN	39	C	+0.8/yr	PM2.5
Benton, Washington	WA	38	C	+0.8/yr	PM2.5
Middlesex, Massachusetts	MA	39	C	+0.8/yr	Ozone
Lincoln, Montana	MT	52	C	+0.8/yr	PM2.5
Stevens, Washington	WA	42	C	+0.8/yr	PM2.5
Bradford, Pennsylvania	PA	40	C	+0.8/yr	Ozone
Weld, Colorado	CO	53	D	+0.8/yr	Ozone
Eau Claire, Wisconsin	WI	42	C	+0.8/yr	PM2.5
Osage, Oklahoma	OK	40	C	+0.8/yr	Ozone
Garfield, Colorado	CO	50	C	+0.8/yr	Ozone
Grant, Wisconsin	WI	42	C	+0.8/yr	PM2.5
Washington, Georgia	GA	47	C	+0.8/yr	PM2.5
Oklahoma, Oklahoma	OK	53	C	+0.8/yr	PM2.5
Mille Lacs, Minnesota	MN	35	C	+0.8/yr	Ozone
McLennan, Texas	TX	43	C	+0.8/yr	Ozone
Sequoyah, Oklahoma	OK	41	C	+0.8/yr	PM2.5
Eddy, New Mexico	NM	47	D	+0.8/yr	Ozone
Chippewa, Michigan	MI	43	C	+0.7/yr	PM2.5
Ottawa, Michigan	MI	44	C	+0.7/yr	Ozone
Ashland, Wisconsin	WI	36	C	+0.7/yr	Ozone
Duval, Florida	FL	52	C	+0.7/yr	PM2.5
Fajardo, Puerto Rico	PR	28	B	+0.7/yr	PM2.5
Yakima, Washington	WA	49	C	+0.7/yr	PM2.5
Meade, South Dakota	SD	39	C	+0.7/yr	Ozone
Merrimack, New Hampshire	NH	37	C	+0.7/yr	Ozone
Pima, Arizona	AZ	53	C	+0.7/yr	Ozone
Prince William, Virginia	VA	35	C	+0.7/yr	Ozone
Canadian, Oklahoma	OK	40	C	+0.7/yr	Ozone
Belmont, Ohio	OH	18	B	+0.7/yr	NO2
Hamilton, Tennessee	TN	49	C	+0.7/yr	PM2.5
Sedgwick, Kansas	KS	45	C	+0.7/yr	Ozone
Seminole, Florida	FL	41	C	+0.7/yr	Ozone
Plumas, California	CA	52	D	+0.7/yr	PM2.5
Washington, Arkansas	AR	46	C	+0.7/yr	PM2.5
Taos, New Mexico	NM	23	B	+0.7/yr	PM2.5
Tooele, Utah	UT	44	C	+0.7/yr	Ozone
Crittenden, Arkansas	AR	45	C	+0.6/yr	PM2.5
Grand, Colorado	CO	46	C	+0.6/yr	Ozone
Saint Clair, Illinois	IL	50	C	+0.6/yr	PM2.5
Christian, Kentucky	KY	45	C	+0.6/yr	Ozone
Cleveland, Oklahoma	OK	51	C	+0.6/yr	PM2.5
Ford, Kansas	KS	15	B	+0.6/yr	PM10
Hamilton, Illinois	IL	46	C	+0.6/yr	PM2.5
Oliver, North Dakota	ND	39	C	+0.6/yr	Ozone
Tarrant, Texas	TX	53	D	+0.6/yr	PM2.5
Escambia, Florida	FL	49	C	+0.6/yr	PM2.5
Okanogan, Washington	WA	49	C	+0.6/yr	PM2.5
Pittsburg, Oklahoma	OK	47	C	+0.6/yr	PM2.5
Galveston, Texas	TX	45	C	+0.6/yr	Ozone
Moffat, Colorado	CO	42	C	+0.6/yr	Ozone
Jasper, Missouri	MO	39	C	+0.6/yr	Ozone
Madison, Illinois	IL	55	C	+0.6/yr	PM2.5
Ottawa, Oklahoma	OK	51	C	+0.6/yr	PM2.5
Salt Lake, Utah	UT	57	D	+0.6/yr	Ozone
Ada, Idaho	ID	45	C	+0.6/yr	Ozone
Jackson, Missouri	MO	51	C	+0.6/yr	PM2.5
Lehigh, Pennsylvania	PA	43	C	+0.6/yr	PM2.5
Pickens, South Carolina	SC	44	C	+0.6/yr	Ozone
Burke, North Dakota	ND	38	C	+0.6/yr	Ozone
Burleigh, North Dakota	ND	38	C	+0.6/yr	PM2.5
Cameron, Texas	TX	52	C	+0.6/yr	PM2.5
Indiana, Pennsylvania	PA	40	C	+0.6/yr	Ozone
Jersey, Illinois	IL	46	C	+0.6/yr	PM2.5
Creek, Oklahoma	OK	39	C	+0.6/yr	Ozone
Harrison, Texas	TX	46	C	+0.6/yr	PM2.5
Johnston, Oklahoma	OK	41	C	+0.6/yr	Ozone
Sauk, Wisconsin	WI	42	C	+0.6/yr	PM2.5
Cumberland, New Jersey	NJ	42	C	+0.5/yr	Ozone
Harris, Texas	TX	59	D	+0.5/yr	PM2.5
Macomb, Michigan	MI	44	C	+0.5/yr	Ozone
Bossier, Louisiana	LA	47	C	+0.5/yr	PM2.5
Josephine, Oregon	OR	38	C	+0.5/yr	PM2.5
Kleberg, Texas	TX	45	C	+0.5/yr	PM2.5
Duchesne, Utah	UT	48	C	+0.5/yr	Ozone
Forest, Wisconsin	WI	38	C	+0.5/yr	Ozone
Greene, Pennsylvania	PA	41	C	+0.5/yr	Ozone
Trego, Kansas	KS	41	C	+0.5/yr	Ozone
Waukesha, Wisconsin	WI	48	C	+0.5/yr	PM2.5
Bay, Florida	FL	47	C	+0.5/yr	PM2.5
Bremer, Iowa	IA	38	C	+0.5/yr	Ozone
Portage, Ohio	OH	40	C	+0.5/yr	Ozone
Iberville, Louisiana	LA	40	C	+0.5/yr	Ozone
Lake, Minnesota	MN	33	C	+0.5/yr	PM2.5
Uintah, Utah	UT	51	D	+0.5/yr	Ozone
Allen, Ohio	OH	42	C	+0.5/yr	Ozone
Dodge, Wisconsin	WI	44	C	+0.5/yr	Ozone
La Crosse, Wisconsin	WI	42	C	+0.5/yr	PM2.5
Goodhue, Minnesota	MN	38	C	+0.5/yr	Ozone
Kitsap, Washington	WA	25	B	+0.5/yr	PM2.5
Boone, Kentucky	KY	40	C	+0.5/yr	Ozone
Pueblo, Colorado	CO	27	B	+0.5/yr	PM2.5
Rockdale, Georgia	GA	39	C	+0.5/yr	Ozone
Stark, Ohio	OH	51	C	+0.5/yr	PM2.5
Volusia, Florida	FL	44	C	+0.5/yr	PM2.5
Cass, North Dakota	ND	41	C	+0.5/yr	Ozone
Champaign, Illinois	IL	45	C	+0.5/yr	PM2.5
Linn, Oregon	OR	35	C	+0.5/yr	PM2.5
Nye, Nevada	NV	20	B	+0.5/yr	PM10
Brookings, South Dakota	SD	40	C	+0.5/yr	Ozone
Cuyahoga, Ohio	OH	56	C	+0.5/yr	PM2.5
Holmes, Florida	FL	48	C	+0.5/yr	PM2.5
Macon, Illinois	IL	49	C	+0.5/yr	PM2.5
McHenry, Illinois	IL	49	C	+0.5/yr	PM2.5
Taylor, Wisconsin	WI	39	C	+0.5/yr	Ozone
Crow Wing, Minnesota	MN	36	C	+0.4/yr	PM2.5
Dane, Wisconsin	WI	46	C	+0.4/yr	PM2.5
Adams, Colorado	CO	50	C	+0.4/yr	Ozone
Douglas, Colorado	CO	47	D	+0.4/yr	Ozone
Fergus, Montana	MT	40	C	+0.4/yr	Ozone
Johnson, Iowa	IA	48	C	+0.4/yr	PM2.5
Knox, Nebraska	NE	37	C	+0.4/yr	Ozone
Steuben, New York	NY	38	C	+0.4/yr	Ozone
Williamson, Tennessee	TN	40	C	+0.4/yr	Ozone
Butte, Idaho	ID	42	C	+0.4/yr	Ozone
Essex, New Jersey	NJ	45	C	+0.4/yr	PM2.5
Fayette, Pennsylvania	PA	43	C	+0.4/yr	PM2.5
Gilpin, Colorado	CO	46	C	+0.4/yr	Ozone
Kanawha, West Virginia	WV	42	C	+0.4/yr	PM2.5
Olmsted, Minnesota	MN	41	C	+0.4/yr	PM2.5
Smith, Texas	TX	36	C	+0.4/yr	Ozone
Adams, Illinois	IL	40	C	+0.4/yr	Ozone
Beltrami, Minnesota	MN	27	B	+0.4/yr	PM2.5
Davis, Utah	UT	46	C	+0.4/yr	Ozone
Dukes, Massachusetts	MA	37	C	+0.4/yr	Ozone
Onondaga, New York	NY	38	C	+0.4/yr	Ozone
Ozaukee, Wisconsin	WI	42	C	+0.4/yr	PM2.5
Travis, Texas	TX	52	C	+0.4/yr	PM2.5
Cerro Gordo, Iowa	IA	18	B	+0.4/yr	PM10
Lee, Mississippi	MS	38	C	+0.4/yr	Ozone
Mercer, North Dakota	ND	38	C	+0.4/yr	Ozone
Sheridan, Wyoming	WY	41	C	+0.4/yr	Ozone
Collin, Texas	TX	39	C	+0.4/yr	Ozone
Washington, Oklahoma	OK	47	C	+0.4/yr	PM2.5
Kalamazoo, Michigan	MI	47	C	+0.4/yr	PM2.5
Kings, New York	NY	39	C	+0.4/yr	PM2.5
Linn, Iowa	IA	49	C	+0.4/yr	PM2.5
Love, Oklahoma	OK	44	C	+0.4/yr	Ozone
San Miguel, Colorado	CO	47	C	+0.4/yr	Ozone
Dunn, North Dakota	ND	37	C	+0.3/yr	Ozone
Durham, North Carolina	NC	49	C	+0.3/yr	PM2.5
Harrison, Iowa	IA	40	C	+0.3/yr	Ozone
Middlesex, New Jersey	NJ	43	C	+0.3/yr	PM2.5
Park, Colorado	CO	49	C	+0.3/yr	Ozone
Putnam, Florida	FL	16	B	+0.3/yr	PM10
Santa Cruz, Arizona	AZ	43	C	+0.3/yr	PM2.5
Knox, Indiana	IN	36	C	+0.3/yr	Ozone
New Hanover, North Carolina	NC	39	C	+0.3/yr	PM2.5
Powder River, Montana	MT	41	C	+0.3/yr	Ozone
Terrebonne, Louisiana	LA	38	C	+0.3/yr	PM2.5
Carter, Oklahoma	OK	45	C	+0.3/yr	PM2.5
Clarke, Georgia	GA	49	C	+0.3/yr	PM2.5
Franklin, Pennsylvania	PA	36	B	+0.3/yr	Ozone
Marion, Oregon	OR	37	C	+0.3/yr	PM2.5
Pulaski, Kentucky	KY	42	C	+0.3/yr	Ozone
Union, Arkansas	AR	47	C	+0.3/yr	PM2.5
Gilmer, West Virginia	WV	32	B	+0.3/yr	Ozone
Jackson, Colorado	CO	21	B	+0.3/yr	PM2.5
Placer, California	CA	54	D	+0.3/yr	Ozone
Walla Walla, Washington	WA	25	B	+0.3/yr	PM2.5
Woodbury, Iowa	IA	40	C	+0.3/yr	PM2.5
Kennebec, Maine	ME	33	B	+0.3/yr	Ozone
Milwaukee, Wisconsin	WI	49	C	+0.3/yr	PM2.5
Richmond, Georgia	GA	51	C	+0.3/yr	PM2.5
Brevard, Florida	FL	43	C	+0.3/yr	PM2.5
Kittitas, Washington	WA	28	B	+0.3/yr	PM2.5
Sandoval, New Mexico	NM	44	C	+0.3/yr	Ozone

Frequently Asked Questions

244 of 1,020 monitored US cities currently show worsening air quality trends based on 10-year EPA data.

Worsening air quality is most commonly caused by increasing wildfire smoke (especially in western states), growing traffic and urban sprawl, industrial activity, and climate change increasing ozone formation on hot days.

Trend is calculated using a linear regression of annual median AQI values over the most recent 10 years of data. Cities with a slope below -0.1 AQI/year are classified as Improving, above +0.1 as Worsening, and between as Stable.

Sources: EPA Air Quality System (AQS)

Last updated: April 2026

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