Cities Where Air Quality Is Improving

These cities show a statistically declining AQI trend over the past decade, meaning air quality is getting better year over year.

346

Improving Cities

Avg AQI (5yr)

33.9%

Of All Cities

Improving Worsening Stable

All Improving Cities

City	State	5yr Avg AQI	Grade	Trend	Worst Pollutant
Hawaii, Hawaii	HI	25	A	-5.2/yr	PM2.5
Carbon, Wyoming	WY	16	A	-4.8/yr	Ozone
Uinta, Wyoming	WY	21	A	-4.5/yr	Ozone
Rosebud, Montana	MT	23	A	-3.6/yr	Ozone
St Croix, Virgin Islands	VI	27	A	-3.5/yr	PM2.5
Monroe, Michigan	MI	21	A	-3.2/yr	PM10
Matanuska-Susitna, Alaska	AK	17	A	-2.7/yr	PM2.5
Alexandria City, Virginia	VA	6	A	-2.5/yr	PM10
Napa, California	CA	39	B	-2.3/yr	PM2.5
Colleton, South Carolina	SC	26	A	-2.3/yr	PM2.5
Caguas, Puerto Rico	PR	10	A	-2.3/yr	NO2
Humboldt, California	CA	28	A	-2.3/yr	Ozone
Wyoming, Pennsylvania	PA	33	A	-2.1/yr	PM2.5
Jefferson, Oregon	OR	28	A	-2.0/yr	PM2.5
Cook, Minnesota	MN	12	A	-2.0/yr	PM2.5
Floyd, Indiana	IN	36	A	-2.0/yr	Ozone
Floyd, Georgia	GA	43	B	-1.9/yr	PM2.5
Juncos, Puerto Rico	PR	9	A	-1.9/yr	Ozone
Douglas, Nevada	NV	22	A	-1.8/yr	PM2.5
Jackson, Indiana	IN	35	A	-1.8/yr	Ozone
Fairbanks North Star, Alaska	AK	42	C	-1.7/yr	PM2.5
Jackson, North Carolina	NC	35	A	-1.7/yr	Ozone
Morgan, Indiana	IN	35	A	-1.7/yr	Ozone
Adjuntas, Puerto Rico	PR	19	A	-1.7/yr	PM2.5
Roane, Tennessee	TN	36	A	-1.7/yr	PM2.5
Fresno, California	CA	68	D	-1.7/yr	Ozone
Kern, California	CA	77	D	-1.7/yr	Ozone
Allen, Indiana	IN	42	B	-1.7/yr	PM2.5
Mercer, Pennsylvania	PA	42	B	-1.6/yr	Ozone
Pike, Kentucky	KY	39	B	-1.6/yr	PM2.5
Tuscaloosa, Alabama	AL	37	A	-1.6/yr	Ozone
Howard, Maryland	MD	37	B	-1.6/yr	PM2.5
Clermont, Ohio	OH	42	B	-1.6/yr	PM2.5
Westmoreland, Pennsylvania	PA	42	B	-1.5/yr	PM2.5
Orleans, Louisiana	LA	36	B	-1.5/yr	PM2.5
Anchorage, Alaska	AK	26	A	-1.4/yr	PM2.5
Luna, New Mexico	NM	17	A	-1.4/yr	PM10
Madera, California	CA	56	C	-1.4/yr	Ozone
Suffolk, Massachusetts	MA	44	B	-1.4/yr	PM2.5
Marion, West Virginia	WV	38	B	-1.4/yr	PM2.5
Taney, Missouri	MO	26	A	-1.4/yr	PM2.5
Prince George's, Maryland	MD	42	B	-1.4/yr	Ozone
Marin, California	CA	36	B	-1.4/yr	PM2.5
Lemhi, Idaho	ID	40	B	-1.4/yr	PM2.5
Northampton, Pennsylvania	PA	44	B	-1.4/yr	PM2.5
Maui, Hawaii	HI	21	A	-1.4/yr	PM2.5
Montgomery, Tennessee	TN	35	B	-1.4/yr	PM2.5
San Joaquin, California	CA	50	C	-1.4/yr	PM2.5
Hughes, South Dakota	SD	13	A	-1.3/yr	PM2.5
Silver Bow, Montana	MT	27	B	-1.3/yr	PM2.5
Martin, North Carolina	NC	35	B	-1.3/yr	Ozone
Cobb, Georgia	GA	41	B	-1.3/yr	Ozone
St John, Virgin Islands	VI	21	A	-1.3/yr	PM2.5
Deschutes, Oregon	OR	25	B	-1.3/yr	PM2.5
Kings, California	CA	64	D	-1.3/yr	Ozone
Garfield, Washington	WA	20	A	-1.3/yr	PM2.5
Bucks, Pennsylvania	PA	37	B	-1.2/yr	Ozone
Ravalli, Montana	MT	22	B	-1.2/yr	PM2.5
Bay, Michigan	MI	32	B	-1.2/yr	PM2.5
Elkhart, Indiana	IN	43	B	-1.2/yr	PM2.5
Howard, Indiana	IN	44	B	-1.2/yr	PM2.5
Monroe, Pennsylvania	PA	35	B	-1.2/yr	Ozone
Chester, Pennsylvania	PA	45	B	-1.2/yr	PM2.5
Erie, Pennsylvania	PA	39	B	-1.2/yr	PM2.5
Athens, Ohio	OH	30	B	-1.2/yr	PM2.5
Baltimore (City), Maryland	MD	43	B	-1.2/yr	PM2.5
Caswell, North Carolina	NC	37	B	-1.2/yr	Ozone
Ellis, Texas	TX	41	B	-1.2/yr	PM2.5
New York, New York	NY	44	B	-1.2/yr	PM2.5
Lebanon, Pennsylvania	PA	46	B	-1.1/yr	PM2.5
Maverick, Texas	TX	35	B	-1.1/yr	PM2.5
Mitchell, North Carolina	NC	30	B	-1.1/yr	PM2.5
Scott, Iowa	IA	52	B	-1.1/yr	PM2.5
Hartford, Connecticut	CT	42	B	-1.1/yr	PM2.5
Lake, Ohio	OH	41	B	-1.1/yr	PM2.5
Sarpy, Nebraska	NE	38	B	-1.1/yr	PM2.5
Warren, Ohio	OH	45	B	-1.1/yr	PM2.5
Lubbock, Texas	TX	28	B	-1.1/yr	PM2.5
Riverside, California	CA	82	D	-1.1/yr	Ozone
Orange, California	CA	54	C	-1.1/yr	PM2.5
Black Hawk, Iowa	IA	45	B	-1.1/yr	PM2.5
Ventura, California	CA	50	C	-1.1/yr	PM2.5
San Juan, Puerto Rico	PR	10	A	-1.1/yr	CO
Salem City, Virginia	VA	34	B	-1.1/yr	PM2.5
Cumberland, Pennsylvania	PA	46	B	-1.1/yr	PM2.5
Aroostook, Maine	ME	36	B	-1.0/yr	PM2.5
Skagit, Washington	WA	28	B	-1.0/yr	PM2.5
Solano, California	CA	45	B	-1.0/yr	PM2.5
Greene, Ohio	OH	41	B	-1.0/yr	PM2.5
Hardin, Kentucky	KY	44	B	-1.0/yr	PM2.5
Harrison, West Virginia	WV	37	B	-1.0/yr	PM2.5
Orange, Florida	FL	38	B	-1.0/yr	Ozone
Androscoggin, Maine	ME	34	B	-1.0/yr	PM2.5
Campbell, Kentucky	KY	44	B	-1.0/yr	PM2.5
Lynchburg City, Virginia	VA	31	B	-1.0/yr	PM2.5
San Luis Obispo, California	CA	51	C	-1.0/yr	PM2.5
Fayette, Texas	TX	34	B	-1.0/yr	PM2.5
Clay, Alabama	AL	37	B	-1.0/yr	PM2.5
Juneau, Alaska	AK	22	A	-1.0/yr	PM2.5
Armstrong, Pennsylvania	PA	45	B	-1.0/yr	PM2.5
Calaveras, California	CA	44	B	-1.0/yr	Ozone
Posey, Indiana	IN	34	B	-1.0/yr	Ozone
Richmond, New York	NY	41	B	-1.0/yr	PM2.5
Wasco, Oregon	OR	24	B	-1.0/yr	PM2.5
Berks, Pennsylvania	PA	46	B	-1.0/yr	PM2.5
Box Elder, Utah	UT	39	B	-1.0/yr	Ozone
Putnam, Tennessee	TN	34	B	-1.0/yr	PM2.5
Hudson, New Jersey	NJ	44	B	-0.9/yr	PM2.5
Jefferson, Ohio	OH	50	B	-0.9/yr	PM2.5
Lexington, South Carolina	SC	42	B	-0.9/yr	PM2.5
Rockingham, New Hampshire	NH	40	B	-0.9/yr	Ozone
Los Angeles, California	CA	75	D	-0.9/yr	PM2.5
Muscatine, Iowa	IA	44	B	-0.9/yr	PM2.5
Bristol City, Virginia	VA	35	B	-0.9/yr	PM2.5
Carroll, Indiana	IN	34	B	-0.9/yr	Ozone
Merced, California	CA	54	C	-0.9/yr	Ozone
Perry, Indiana	IN	36	B	-0.9/yr	Ozone
Lackawanna, Pennsylvania	PA	41	B	-0.9/yr	PM2.5
Tulare, California	CA	75	D	-0.9/yr	Ozone
Washington, Pennsylvania	PA	50	B	-0.9/yr	PM2.5
Warrick, Indiana	IN	36	B	-0.9/yr	Ozone
Chesterfield, South Carolina	SC	39	B	-0.9/yr	PM2.5
Kent, Maryland	MD	40	B	-0.9/yr	Ozone
Maury, Tennessee	TN	33	B	-0.9/yr	PM2.5
Saint Louis, Missouri	MO	45	B	-0.9/yr	PM2.5
Washington, Minnesota	MN	37	B	-0.9/yr	Ozone
Fairfield, Connecticut	CT	46	C	-0.9/yr	PM2.5
Thurston, Washington	WA	27	B	-0.9/yr	PM2.5
Union, Oregon	OR	27	B	-0.9/yr	PM2.5
Blair, Pennsylvania	PA	44	B	-0.9/yr	PM2.5
Kay, Oklahoma	OK	48	B	-0.9/yr	PM2.5
Twin Falls, Idaho	ID	27	B	-0.9/yr	PM2.5
Boone, Indiana	IN	35	B	-0.9/yr	Ozone
Nassau, Florida	FL	42	B	-0.9/yr	PM2.5
Oconee, South Carolina	SC	37	B	-0.9/yr	Ozone
Butte, California	CA	52	C	-0.8/yr	PM2.5
Charlton, Georgia	GA	26	B	-0.8/yr	PM2.5
Montgomery, Maryland	MD	41	B	-0.8/yr	PM2.5
Cecil, Maryland	MD	42	B	-0.8/yr	PM2.5
East Baton Rouge, Louisiana	LA	48	B	-0.8/yr	PM2.5
Lawrence, Tennessee	TN	33	B	-0.8/yr	PM2.5
Washington, Maryland	MD	42	B	-0.8/yr	PM2.5
Jefferson, Missouri	MO	43	B	-0.8/yr	PM2.5
Van Buren, Iowa	IA	43	B	-0.8/yr	PM2.5
Northampton, North Carolina	NC	35	B	-0.8/yr	PM2.5
Bayamon, Puerto Rico	PR	18	A	-0.8/yr	CO
Shoshone, Idaho	ID	43	B	-0.8/yr	PM2.5
San Mateo, California	CA	36	B	-0.8/yr	PM2.5
Santa Barbara, California	CA	46	B	-0.8/yr	PM2.5
Wake, North Carolina	NC	48	B	-0.8/yr	PM2.5
Imperial, California	CA	61	D	-0.8/yr	PM2.5
Muskogee, Oklahoma	OK	18	A	-0.8/yr	PM10
Clayton, Georgia	GA	45	B	-0.8/yr	PM2.5
Hyde, North Carolina	NC	23	B	-0.8/yr	PM2.5
Scotts Bluff, Nebraska	NE	24	B	-0.8/yr	PM2.5
Cowlitz, Washington	WA	22	B	-0.8/yr	PM2.5
Harford, Maryland	MD	44	B	-0.8/yr	PM2.5
Miami-Dade, Florida	FL	45	B	-0.8/yr	PM2.5
Penobscot, Maine	ME	33	B	-0.8/yr	PM2.5
Rapides, Louisiana	LA	39	B	-0.8/yr	PM2.5
Cass, Nebraska	NE	16	A	-0.7/yr	PM10
Delaware, Pennsylvania	PA	51	C	-0.7/yr	PM2.5
Erie, New York	NY	44	B	-0.7/yr	PM2.5
Shelby, Indiana	IN	35	B	-0.7/yr	Ozone
Anne Arundel, Maryland	MD	40	B	-0.7/yr	Ozone
Kauai, Hawaii	HI	15	A	-0.7/yr	PM2.5
LaPorte, Indiana	IN	37	B	-0.7/yr	Ozone
Palo Alto, Iowa	IA	43	B	-0.7/yr	PM2.5
Coffee, Georgia	GA	36	B	-0.7/yr	PM2.5
Buchanan, Missouri	MO	44	B	-0.7/yr	PM2.5
Tippecanoe, Indiana	IN	43	B	-0.7/yr	PM2.5
Davidson, North Carolina	NC	46	B	-0.7/yr	PM2.5
DeKalb, Georgia	GA	50	C	-0.7/yr	PM2.5
Dubois, Indiana	IN	43	B	-0.7/yr	PM2.5
Guayama, Puerto Rico	PR	24	B	-0.7/yr	PM2.5
Honolulu, Hawaii	HI	29	B	-0.7/yr	Ozone
Macoupin, Illinois	IL	33	B	-0.7/yr	Ozone
San Bernardino, California	CA	82	F	-0.7/yr	Ozone
Cass, Missouri	MO	41	B	-0.7/yr	PM2.5
Etowah, Alabama	AL	43	B	-0.7/yr	PM2.5
Garfield, Utah	UT	36	B	-0.7/yr	Ozone
Lawrence, Alabama	AL	29	B	-0.7/yr	PM2.5
Lucas, Ohio	OH	44	B	-0.7/yr	PM2.5
Jefferson, Washington	WA	22	B	-0.7/yr	PM2.5
Lyon, Nevada	NV	39	B	-0.7/yr	Ozone
Spencer, Indiana	IN	42	B	-0.7/yr	PM2.5
Franklin, Idaho	ID	25	B	-0.7/yr	PM2.5
Lafayette, Louisiana	LA	45	B	-0.7/yr	PM2.5
Ohio, West Virginia	WV	40	B	-0.7/yr	Ozone
Catawba, North Carolina	NC	44	B	-0.7/yr	PM2.5
Columbia, Georgia	GA	35	B	-0.7/yr	Ozone
Ector, Texas	TX	36	B	-0.7/yr	PM2.5
Kootenai, Idaho	ID	30	B	-0.7/yr	PM2.5
Orange, New York	NY	37	B	-0.7/yr	Ozone
Richland, South Carolina	SC	43	B	-0.7/yr	PM2.5
Stoddard, Missouri	MO	31	B	-0.7/yr	PM2.5
Washington, Nebraska	NE	31	B	-0.7/yr	PM2.5
San Francisco, California	CA	38	B	-0.6/yr	PM2.5
Stafford, Virginia	VA	36	B	-0.6/yr	Ozone
Clark, Illinois	IL	34	B	-0.6/yr	Ozone
District of Columbia, District Of Columbia	DC	49	C	-0.6/yr	PM2.5
Garrett, Maryland	MD	39	B	-0.6/yr	Ozone
Berkshire, Massachusetts	MA	42	B	-0.6/yr	PM2.5
Centre, Pennsylvania	PA	44	B	-0.6/yr	PM2.5
Douglas, Nebraska	NE	43	B	-0.6/yr	PM2.5
Winona, Minnesota	MN	23	B	-0.6/yr	PM2.5
Lewis, Washington	WA	25	B	-0.6/yr	PM2.5
Mason, Washington	WA	24	B	-0.6/yr	PM2.5
Hennepin, Minnesota	MN	47	C	-0.6/yr	PM2.5
Weber, Utah	UT	46	C	-0.6/yr	Ozone
Clinton, Iowa	IA	51	C	-0.6/yr	PM2.5
Grays Harbor, Washington	WA	25	B	-0.6/yr	PM2.5
Montgomery, Iowa	IA	41	B	-0.6/yr	PM2.5
Whatcom, Washington	WA	29	B	-0.6/yr	PM2.5
Oneida, New York	NY	25	B	-0.6/yr	PM2.5
York, Pennsylvania	PA	47	B	-0.6/yr	PM2.5
Columbiana, Ohio	OH	12	A	-0.6/yr	PM10
King, Washington	WA	45	C	-0.6/yr	PM2.5
Amador, California	CA	37	B	-0.6/yr	Ozone
Calvert, Maryland	MD	39	B	-0.6/yr	Ozone
Providence, Rhode Island	RI	45	B	-0.6/yr	PM2.5
Sacramento, California	CA	53	C	-0.6/yr	Ozone
Windham, Vermont	VT	12	A	-0.6/yr	PM2.5
Florence, South Carolina	SC	42	B	-0.6/yr	PM2.5
Greene, Indiana	IN	39	B	-0.6/yr	Ozone
Henry, Georgia	GA	40	B	-0.6/yr	PM2.5
Medina, Ohio	OH	42	B	-0.6/yr	PM2.5
New Haven, Connecticut	CT	45	C	-0.6/yr	PM2.5
Pinal, Arizona	AZ	66	D	-0.6/yr	PM10
Sonoma, California	CA	36	B	-0.6/yr	Ozone
Webb, Texas	TX	47	B	-0.6/yr	PM2.5
Westchester, New York	NY	38	B	-0.6/yr	Ozone
Yolo, California	CA	43	B	-0.6/yr	Ozone
Stanislaus, California	CA	57	D	-0.5/yr	PM2.5
Charles, Maryland	MD	39	B	-0.5/yr	Ozone
Lawrence, Ohio	OH	44	B	-0.5/yr	PM2.5
McMinn, Tennessee	TN	39	B	-0.5/yr	PM2.5
New Castle, Delaware	DE	48	C	-0.5/yr	PM2.5
Alameda, California	CA	50	C	-0.5/yr	PM2.5
Jefferson, Tennessee	TN	41	B	-0.5/yr	Ozone
Cambria, Pennsylvania	PA	48	B	-0.5/yr	PM2.5
Edgecombe, North Carolina	NC	38	B	-0.5/yr	PM2.5
Huntington, Indiana	IN	31	B	-0.5/yr	Ozone
Lake, California	CA	32	B	-0.5/yr	Ozone
Nassau, New York	NY	30	B	-0.5/yr	PM2.5
Wood, West Virginia	WV	39	B	-0.5/yr	Ozone
Dorchester, Maryland	MD	41	B	-0.5/yr	Ozone
Glenn, California	CA	43	C	-0.5/yr	Ozone
Hopewell City, Virginia	VA	7	A	-0.5/yr	PM10
Sutter, California	CA	52	C	-0.5/yr	PM2.5
Winchester City, Virginia	VA	7	A	-0.5/yr	PM10
Dyer, Tennessee	TN	37	B	-0.5/yr	PM2.5
Oakland, Michigan	MI	39	B	-0.5/yr	Ozone
Arkansas, Arkansas	AR	40	B	-0.5/yr	PM2.5
Brown, South Dakota	SD	26	B	-0.5/yr	PM2.5
Clallam, Washington	WA	37	B	-0.5/yr	PM2.5
Darlington, South Carolina	SC	36	B	-0.5/yr	Ozone
Genesee, Michigan	MI	42	B	-0.5/yr	PM2.5
Sumter, Alabama	AL	36	B	-0.5/yr	PM2.5
Tuolumne, California	CA	41	B	-0.5/yr	Ozone
Berkeley, West Virginia	WV	40	B	-0.5/yr	Ozone
Cass, Michigan	MI	40	B	-0.5/yr	Ozone
Shelby, Alabama	AL	38	B	-0.5/yr	Ozone
Vigo, Indiana	IN	49	C	-0.5/yr	PM2.5
Georgetown, South Carolina	SC	14	A	-0.5/yr	PM10
Greenbrier, West Virginia	WV	37	B	-0.5/yr	Ozone
Ingham, Michigan	MI	42	B	-0.5/yr	PM2.5
Loudon, Tennessee	TN	41	B	-0.5/yr	PM2.5
Alamosa, Colorado	CO	14	A	-0.5/yr	PM10
Buncombe, North Carolina	NC	40	B	-0.5/yr	PM2.5
Philadelphia, Pennsylvania	PA	52	C	-0.5/yr	PM2.5
Union, North Carolina	NC	40	B	-0.5/yr	Ozone
Clay, Missouri	MO	41	B	-0.4/yr	Ozone
Leon, Florida	FL	47	B	-0.4/yr	PM2.5
Berrien, Michigan	MI	40	B	-0.4/yr	Ozone
Bonneville, Idaho	ID	30	B	-0.4/yr	PM2.5
Camden, New Jersey	NJ	49	C	-0.4/yr	PM2.5
Cheshire, New Hampshire	NH	38	B	-0.4/yr	PM2.5
Bartholomew, Indiana	IN	43	B	-0.4/yr	PM2.5
Bronx, New York	NY	46	C	-0.4/yr	PM2.5
Brown, Indiana	IN	35	B	-0.4/yr	Ozone
Clinton, Michigan	MI	36	B	-0.4/yr	Ozone
Rockland, New York	NY	38	B	-0.4/yr	Ozone
Boyd, Kentucky	KY	44	B	-0.4/yr	PM2.5
Cumberland, Maine	ME	40	B	-0.4/yr	PM2.5
Dauphin, Pennsylvania	PA	48	C	-0.4/yr	PM2.5
Lowndes, Georgia	GA	46	B	-0.4/yr	PM2.5
Adams, Washington	WA	18	B	-0.4/yr	PM2.5
Alexander, North Carolina	NC	38	B	-0.4/yr	Ozone
Arlington, Virginia	VA	37	B	-0.4/yr	Ozone
Iron, Utah	UT	42	B	-0.4/yr	Ozone
Litchfield, Connecticut	CT	38	B	-0.4/yr	Ozone
Hall, Georgia	GA	47	C	-0.4/yr	PM2.5
Hamilton, Ohio	OH	55	C	-0.4/yr	PM2.5
Mesa, Colorado	CO	45	B	-0.4/yr	Ozone
Minnehaha, South Dakota	SD	39	B	-0.4/yr	Ozone
St. Tammany, Louisiana	LA	40	B	-0.4/yr	PM2.5
Tioga, Pennsylvania	PA	39	B	-0.4/yr	Ozone
Caroline, Virginia	VA	37	B	-0.4/yr	Ozone
Norfolk City, Virginia	VA	18	A	-0.4/yr	NO2
St. Martin, Louisiana	LA	34	B	-0.4/yr	Ozone
Colbert, Alabama	AL	38	B	-0.4/yr	Ozone
Grafton, New Hampshire	NH	36	B	-0.4/yr	Ozone
Polk, Florida	FL	43	B	-0.4/yr	PM2.5
Porter, Indiana	IN	46	C	-0.4/yr	PM2.5
Susquehanna, Pennsylvania	PA	32	B	-0.4/yr	PM2.5
Union, New Jersey	NJ	51	C	-0.4/yr	PM2.5
Aiken, South Carolina	SC	36	B	-0.4/yr	Ozone
Churchill, Nevada	NV	41	B	-0.4/yr	Ozone
Henry, Indiana	IN	38	B	-0.4/yr	PM2.5
Mariposa, California	CA	49	C	-0.4/yr	Ozone
Perry, Kentucky	KY	44	B	-0.4/yr	PM2.5
Madison, Virginia	VA	40	B	-0.3/yr	Ozone
McCracken, Kentucky	KY	46	C	-0.3/yr	PM2.5
Mecklenburg, North Carolina	NC	50	C	-0.3/yr	PM2.5
Ouachita, Louisiana	LA	36	B	-0.3/yr	Ozone
Rockwall, Texas	TX	33	B	-0.3/yr	Ozone
Spokane, Washington	WA	41	B	-0.3/yr	PM2.5
Swain, North Carolina	NC	41	B	-0.3/yr	PM2.5
Herkimer, New York	NY	29	B	-0.3/yr	Ozone
Houston, Alabama	AL	38	B	-0.3/yr	Ozone
Jerome, Idaho	ID	17	B	-0.3/yr	PM2.5
Lenoir, North Carolina	NC	37	B	-0.3/yr	Ozone
Atlantic, New Jersey	NJ	38	B	-0.3/yr	Ozone
Clearfield, Pennsylvania	PA	33	B	-0.3/yr	Ozone
Dawson, Georgia	GA	35	B	-0.3/yr	Ozone
Hamilton, Indiana	IN	45	C	-0.3/yr	PM2.5
Lee, Florida	FL	39	B	-0.3/yr	PM2.5
Pitt, North Carolina	NC	39	B	-0.3/yr	PM2.5
Rockbridge, Virginia	VA	35	B	-0.3/yr	Ozone
Ashley, Arkansas	AR	41	B	-0.3/yr	PM2.5
Cascade, Montana	MT	30	B	-0.3/yr	PM2.5
Crook, Oregon	OR	29	B	-0.3/yr	PM2.5
Indian River, Florida	FL	35	B	-0.3/yr	Ozone
Niagara, New York	NY	34	B	-0.3/yr	Ozone
Russell, Alabama	AL	46	B	-0.3/yr	PM2.5
Spartanburg, South Carolina	SC	47	C	-0.3/yr	PM2.5
Suffolk, New York	NY	42	C	-0.3/yr	Ozone
Benzie, Michigan	MI	36	B	-0.3/yr	Ozone
Sussex, Delaware	DE	43	B	-0.3/yr	Ozone
York, Maine	ME	37	B	-0.3/yr	Ozone
Allegan, Michigan	MI	40	B	-0.3/yr	Ozone
Hendricks, Indiana	IN	34	B	-0.3/yr	Ozone
Missoula, Montana	MT	54	C	-0.3/yr	PM2.5
North Slope, Alaska	AK	6	A	-0.3/yr	PM2.5
Ramsey, Minnesota	MN	41	B	-0.3/yr	PM2.5

Frequently Asked Questions

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

Air quality improvements are driven by stricter emission regulations, cleaner vehicle standards, coal plant retirements, and industrial pollution controls. Cities investing in public transit and reducing traffic congestion also see faster gains.

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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