Which county has the highest Median Air Quality Index?

Riverside County, CA has the highest Median Air Quality Index in 2025, at 80, followed by San Bernardino County, CA (77) and Los Angeles County, CA (74).

Which county has the lowest Median Air Quality Index?

Karnes County, TX has the lowest Median Air Quality Index in 2025, at 6.

What is the median Median Air Quality Index across US counties?

The median is 40 across the 960 US counties with data in 2025.

Where does this air quality by county (epa) data come from?

Rankodex compiles it from World Population Review and the primary sources it cites: Air Quality Statistics by County - US Environmental Protection Agency.

County rankings

Air Quality by County (EPA)

Name: Air Quality by County (EPA)
Creator: Rankodex

Riverside County, CA has the highest Median Air Quality Index in 2025 (80), followed by San Bernardino County, CA (77) and Los Angeles County, CA (74). Karnes County, TX has the lowest (6).

Environment Health983 counties · 4 metricsOriginal page

1 source

Air Quality Statistics by County - US Environmental Protection Agency

Showing

Year

960 of 3,094 counties

Compare this metric Add to combined ranking Open full map

Median Air Quality Index, 2025

Green is better, red is worse (lower is better). Click a place to highlight it.

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Ranking

Best first: the first 15 and last 5 of 960 counties.

Distribution Median and middle halfThe median is the middle value: half of places are above it, half below. The middle half is the range holding the central 50% of places.More in the glossary →

How many counties fall in each range; the lines mark the median and the middle half.

Median

Middle half 35 – 44

Average

38.69

960 counties

Lowest (best)

Hopewell city, VA

Highest (worst)

Riverside County, CA

Over time · 2023–2025

The top 5 in 2025, against the median.

Median of all counties
Hopewell city, VA
Karnes County, TX
Carroll County, VA
North Slope Borough, AK
Wilson County, TX

Data

Click a column to sort, a row to highlight that place on the charts.

960 counties · # = rank by Median Air Quality Index

#
1	Hopewell city, VA	6	11	100.0%	0
1	Karnes County, TX	6	16	100.0%	0
3	Carroll County, VA	7	16	100.0%	0
3	North Slope Borough, AK	7	23	97.6%	0
5	Wilson County, TX	8	19	100.0%	0
5	Carbon County, WY	8	33	100.0%	0
5	Keweenaw County, MI	8	16	100.0%	0
8	Sonoma County, CA	9	17	100.0%	0
8	Matanuska-Susitna Borough, AK	9	47	91.5%	2
8	Kenai Peninsula Borough, AK	9	16	100.0%	0
8	Uinta County, WY	9	19	100.0%	0
8	Jackson County, CO	9	26	98.9%	0
13	Lincoln County, WY	10	26	98.9%	0
13	Custer County, ID	10	31	96.9%	0
15	Gallatin County, MT	11	26	98.1%	0
15	Lake County, MT	11	33	96.8%	0
15	Rosebud County, MT	11	27	98.0%	0
15	Aleutians East Borough, AK	11	21	99.0%	0
19	Columbiana County, OH	12	22	100.0%	0
19	Teton County, MT	12	26	97.1%	0
19	Garfield County, UT	12	22	97.7%	0
19	San Juan County, CO	12	29	98.9%	0
23	Navajo County, AZ	13	24	99.5%	0
23	Park County, WY	13	28	98.0%	0
23	Los Alamos County, NM	13	27	100.0%	0
23	Beaverhead County, MT	13	29	94.7%	0
23	Powell County, MT	13	33	94.7%	0
28	Hill County, MT	14	40	92.1%	2
28	Wayne County, UT	14	27	97.9%	0
30	Windham County, VT	15	48	92.0%	1
30	Platte County, WY	15	47	90.6%	12
32	Potter County, TX	16	41	94.1%	0
32	Taos County, NM	16	32	98.9%	0
32	Pacific County, WA	16	26	99.7%	0
32	Sanders County, MT	16	55	82.0%	0
32	Roosevelt County, MT	16	54	87.2%	1
32	Cook County, MN	16	54	88.0%	12
38	Mohave County, AZ	17	34	94.8%	2
38	Blaine County, ID	17	36	96.6%	0
38	Luna County, NM	17	68	84.7%	18
38	Socorro County, NM	17	36	98.0%	0
42	Hughes County, SD	18	45	93.0%	1
42	Dawson County, MT	18	49	90.3%	3
42	Sheridan County, MT	18	54	86.8%	1
45	Marquette County, MI	19	62	82.4%	13
45	Cass County, NE	19	36	95.9%	0
45	Pitkin County, CO	19	43	92.3%	1
45	Phillips County, MT	19	47	91.4%	5
45	Garfield County, WA	19	45	92.5%	0
50	Lewis County, WA	20	48	91.3%	0
50	Jefferson County, WA	20	36	97.3%	0
52	Marin County, CA	21	49	91.6%	0
52	Maui County, HI	21	32	98.1%	0
52	Putnam County, FL	21	43	95.6%	0
52	Winona County, MN	21	55	83.8%	0
52	Ravalli County, MT	21	59	79.2%	1
52	Stoddard County, MO	21	40	100.0%	0
52	Adams County, WA	21	50	90.5%	0
52	Franklin County, ID	21	39	96.3%	0
52	Mono County, CA	21	50	90.1%	7
61	Kitsap County, WA	22	42	95.5%	0
61	Bonneville County, ID	22	43	93.0%	0
61	Cowlitz County, WA	22	49	90.4%	0
61	Grays Harbor County, WA	22	41	97.3%	0
61	Douglas County, NV	22	50	91.1%	0
61	Susquehanna County, PA	22	51	88.4%	2
61	Routt County, CO	22	42	93.7%	0
61	Thomas County, NE	22	43	92.4%	0
69	Deschutes County, OR	23	52	89.3%	3
69	Franklin County, WA	23	52	86.7%	2
69	Mason County, WA	23	48	90.4%	1
69	Fremont County, CO	23	45	93.4%	0
69	Whitman County, WA	23	54	86.8%	0
69	Scotts Bluff County, NE	23	42	95.8%	0
69	Juneau City and Borough, AK	23	58	84.3%	1
69	Pine County, MN	23	45	94.2%	0
69	Klickitat County, WA	23	53	84.6%	1
69	Glacier County, MT	23	44	91.7%	3
79	Lubbock County, TX	24	46	92.9%	2
79	Wyoming County, PA	24	53	86.5%	2
79	Hyde County, NC	24	44	96.9%	0
82	Skagit County, WA	25	40	97.5%	0
82	Kittitas County, WA	25	57	80.0%	3
82	Wasco County, OR	25	54	86.3%	0
82	Alamosa County, CO	25	49	91.5%	0
86	Anchorage Municipality, AK	26	61	79.2%	1
86	Twin Falls County, ID	26	47	92.9%	1
86	Nye County, NV	26	45	92.6%	2
86	Lake County, OR	26	62	80.5%	1
86	Wallowa County, OR	26	53	85.2%	0
91	Orange County, NY	27	53	86.9%	1
91	Thurston County, WA	27	47	93.5%	0
91	Oneida County, NY	27	54	84.4%	0
91	Linn County, OR	27	57	80.0%	1
91	Columbia County, OR	27	45	92.9%	0
91	Brown County, SD	27	56	83.6%	6
91	Sheridan County, WY	27	51	89.1%	0
91	Union County, OR	27	54	84.4%	0
91	Washington County, NE	27	53	86.6%	1
91	Charlton County, GA	27	46	92.6%	0
91	Prowers County, CO	27	45	92.6%	2
91	Sherman County, KS	27	49	90.1%	0
103	Grant County, WA	28	59	79.7%	3
103	Walla Walla County, WA	28	56	80.8%	0
103	Taney County, MO	28	52	89.8%	0
103	Silver Bow County, MT	28	54	84.9%	0
103	Ford County, KS	28	51	89.8%	1
103	Crook County, OR	28	65	72.9%	2
103	Jefferson County, OR	28	63	74.0%	0
103	Harney County, OR	28	60	71.5%	0
111	Nassau County, NY	29	58	78.8%	0
111	Honolulu County, HI	29	39	97.3%	0
111	Clallam County, WA	29	53	85.5%	0
111	Chaves County, NM	29	47	91.9%	2
111	Roane County, TN	29	52	88.6%	0
111	Delta County, CO	29	53	85.6%	1
111	Baker County, OR	29	54	83.3%	0
111	Lemhi County, ID	29	63	71.5%	2
119	Putnam County, TN	30	51	90.0%	0
119	Lynchburg city, VA	30	53	85.2%	0
119	Lawrence County, AL	30	48	91.8%	0
122	Clackamas County, OR	31	53	87.6%	2
122	Whatcom County, WA	31	46	94.0%	1
122	Kootenai County, ID	31	58	77.8%	3
122	Kent County, RI	31	46	92.8%	0
122	Rockwall County, TX	31	45	96.8%	2
122	Lake County, CA	31	39	99.2%	0
122	Athens County, OH	31	54	83.4%	0
122	Latah County, ID	31	57	83.4%	1
122	Salem city, VA	31	54	79.6%	0
122	Martin County, NC	31	41	100.0%	0
122	Trinity County, CA	31	65	69.6%	2
122	Mitchell County, NC	31	54	81.5%	1
122	Lake County, MN	31	60	85.9%	15
122	Grant County, OK	31	53	82.4%	1
122	Chase County, KS	31	54	82.8%	0
137	Montgomery County, TN	32	54	83.8%	1
137	Sarpy County, NE	32	56	78.8%	1
137	Hawaii County, HI	32	53	86.0%	0
137	Pennington County, SD	32	62	77.5%	1
137	Aroostook County, ME	32	57	83.3%	4
137	Belknap County, NH	32	51	88.8%	0
137	Carter County, OK	32	55	81.6%	1
137	Macon County, NC	32	44	96.6%	0
137	Del Norte County, CA	32	54	81.8%	0
137	Culberson County, TX	32	67	76.1%	2
147	Clark County, WA	33	56	82.7%	0
147	Solano County, CA	33	42	99.2%	0
147	Howard County, MD	33	54	80.3%	0
147	Norfolk city, VA	33	53	86.0%	0
147	Penobscot County, ME	33	58	84.2%	6
147	Ascension Parish, LA	33	47	95.6%	1
147	Maury County, TN	33	53	83.5%	0
147	Putnam County, NY	33	46	94.2%	0
147	Wayne County, NY	33	45	95.8%	0
147	Josephine County, OR	33	67	68.2%	8
147	Apache County, AZ	33	58	86.2%	0
147	Harrison County, WV	33	55	72.4%	0
147	Polk County, TX	33	48	94.8%	1
147	Lawrence County, TN	33	53	81.5%	0
147	Nez Perce County, ID	33	63	72.5%	4
147	Knox County, ME	33	44	97.8%	0
147	Carlton County, MN	33	62	82.8%	12
147	Manistee County, MI	33	65	79.5%	9
147	Prince Edward County, VA	33	44	97.8%	0
147	Jo Daviess County, IL	33	46	95.3%	0
147	St. James Parish, LA	33	48	93.9%	0
147	Northampton County, NC	33	55	78.1%	0
147	Clark County, IL	33	48	93.8%	0
147	Clay County, AL	33	55	81.1%	1
147	Schoolcraft County, MI	33	64	83.4%	5
147	Liberty County, FL	33	44	98.5%	0
147	Denali Borough, AK	33	43	99.7%	0
174	Polk County, FL	34	46	95.5%	0
174	Ramsey County, MN	34	61	70.1%	9
174	Virginia Beach city, VA	34	55	80.8%	0
174	St. Lucie County, FL	34	46	96.4%	0
174	Dutchess County, NY	34	46	94.0%	3
174	Washington County, MN	34	46	94.9%	0
174	Erie County, PA	34	59	76.7%	1
174	Saratoga County, NY	34	44	96.3%	0
174	York County, ME	34	45	96.7%	3
174	Niagara County, NY	34	48	92.9%	1
174	Flagler County, FL	34	45	98.1%	0
174	Kennebec County, ME	34	55	85.2%	0
174	Hunt County, TX	34	50	91.7%	1
174	Oswego County, NY	34	44	97.3%	0
174	Androscoggin County, ME	34	54	85.2%	2
174	Jefferson County, NY	34	47	94.6%	0
174	Victoria County, TX	34	58	86.7%	0
174	Elmore County, AL	34	46	97.9%	0
174	Leavenworth County, KS	34	48	94.0%	0
174	Fauquier County, VA	34	44	97.6%	0
174	Hall County, NE	34	54	82.5%	2
174	Pike County, KY	34	52	88.2%	0
174	Macoupin County, IL	34	49	91.8%	1
174	St. John the Baptist Parish, LA	34	48	93.1%	0
174	Dawson County, GA	34	46	95.1%	0
174	Dyer County, TN	34	55	76.9%	0
174	Washington County, ME	34	49	91.5%	0
174	Wabash County, IN	34	49	92.0%	1
174	Mille Lacs County, MN	34	46	95.3%	0
174	DeKalb County, TN	34	46	96.6%	0
174	Gage County, NE	34	58	75.8%	1
174	Clark County, AR	34	46	96.7%	0
174	Taylor County, WI	34	46	95.3%	0
174	Bristol city, VA	34	55	78.0%	0
174	Brown County, IN	34	46	95.9%	0
174	Clay County, SD	34	53	87.7%	2
174	Archuleta County, CO	34	61	83.0%	2
174	Valley County, ID	34	60	73.3%	1
174	Yalobusha County, MS	34	45	96.6%	0
174	Hamilton County, NY	34	44	97.2%	0
214	Cobb County, GA	35	47	93.5%	0
214	Prince William County, VA	35	46	95.6%	0
214	Lake County, FL	35	47	95.0%	1
214	Dakota County, MN	35	62	73.2%	10
214	Brazoria County, TX	35	71	80.8%	8
214	Marion County, OR	35	58	80.0%	0
214	Berkeley County, SC	35	48	93.3%	0
214	Cumberland County, PA	35	62	71.5%	0
214	Santa Cruz County, CA	35	53	87.7%	0
214	Smith County, TX	35	50	90.4%	0
214	Ellis County, TX	35	51	89.2%	0
214	Hendricks County, IN	35	49	92.0%	0
214	Stafford County, VA	35	46	96.4%	0
214	Highlands County, FL	35	47	94.9%	0
214	Tompkins County, NY	35	47	93.2%	0
214	Boone County, IN	35	51	89.7%	3
214	Chelan County, WA	35	68	69.6%	14
214	Carteret County, NC	35	46	96.2%	0
214	Lauderdale County, MS	35	48	94.6%	0
214	Sauk County, WI	35	58	75.6%	6
214	Hancock County, ME	35	49	91.0%	4
214	Lenoir County, NC	35	47	97.6%	0
214	Atascosa County, TX	35	61	76.0%	0
214	Tuscola County, MI	35	49	91.9%	1
214	Stevens County, WA	35	63	69.0%	9
214	Shelby County, IN	35	49	91.4%	1
214	Sagadahoc County, ME	35	47	95.4%	1
214	Warren County, PA	35	58	78.7%	3
214	Caroline County, VA	35	45	96.7%	0
214	Effingham County, IL	35	46	95.5%	0
214	Claiborne County, TN	35	45	97.2%	0
214	Codington County, SD	35	58	78.0%	4
214	Posey County, IN	35	50	90.5%	1
214	Dukes County, MA	35	45	95.9%	2
214	Carroll County, IN	35	49	90.8%	1
214	Benzie County, MI	35	50	91.1%	0
214	Missaukee County, MI	35	58	86.9%	4
214	Morgan County, KY	35	47	94.7%	0
214	Monroe County, MO	35	47	94.0%	0
253	Middlesex County, NJ	36	57	81.5%	1
253	Monmouth County, NJ	36	50	91.3%	6
253	Bucks County, PA	36	61	86.2%	4
253	Washington County, OR	36	57	79.2%	0
253	Manatee County, FL	36	50	91.0%	0
253	Onondaga County, NY	36	57	83.2%	4
253	Canyon County, ID	36	58	77.1%	0
253	Atlantic County, NJ	36	54	82.2%	1
253	Shelby County, AL	36	49	91.4%	0
253	Richmond city, VA	36	54	78.9%	0
253	Barnstable County, MA	36	46	93.7%	3
253	Benton County, WA	36	57	80.3%	2
253	Okaloosa County, FL	36	48	93.9%	0
253	Minnehaha County, SD	36	58	80.8%	4
253	Monroe County, PA	36	52	88.3%	2
253	Hampshire County, MA	36	54	85.5%	4
253	Monroe County, IN	36	58	73.6%	0
253	Marathon County, WI	36	61	76.6%	9
253	Gregg County, TX	36	54	86.6%	1
253	Chautauqua County, NY	36	52	89.0%	1
253	Hanover County, VA	36	46	96.7%	0
253	Madison County, TN	36	56	74.3%	0
253	Rockdale County, GA	36	48	94.6%	0
253	Ozaukee County, WI	36	67	75.9%	15
253	Grafton County, NH	36	54	83.6%	3
253	Bannock County, ID	36	52	88.8%	1
253	Manitowoc County, WI	36	58	87.4%	1
253	Caldwell County, NC	36	46	97.1%	0
253	Somerset County, PA	36	46	94.5%	0
253	Ward County, ND	36	60	79.4%	12
253	St. Martin Parish, LA	36	50	92.2%	0
253	Beltrami County, MN	36	69	79.1%	17
253	Monroe County, WI	36	62	67.5%	9
253	Person County, NC	36	47	95.8%	0
253	Knox County, IN	36	49	91.3%	0
253	Greenup County, KY	36	46	96.9%	0
253	Wexford County, MI	36	48	94.2%	0
253	Meade County, SD	36	46	97.4%	0
253	Elk County, PA	36	47	95.3%	0
253	Mason County, MI	36	51	89.2%	0
253	Perry County, KY	36	52	87.1%	1
253	Carter County, KY	36	51	89.0%	0
253	Vilas County, WI	36	49	92.0%	1
253	Rockbridge County, VA	36	46	93.9%	0
253	Brooke County, WV	36	57	73.1%	0
253	Jackson County, WI	36	63	69.0%	10
253	Perry County, IN	36	49	92.7%	0
253	Ashland County, WI	36	62	81.6%	13

Showing the first 300 of 960 counties, ranked by Median Air Quality Index.

What correlates with Median Air Quality Index (2025)?

Pearson r against 36 other county metrics sharing at least 576 counties. Correlation is not causation.

Higher together

Places that have a higher Median Air Quality Index tend to score higher on these

RapesSafest Counties
r = +0.44 · moderate · n = 579
Plot
Average July Temperature (°F)Climate by County (1991–2020 Averages)
r = +0.42 · moderate · n = 959
Plot
Aggravated AssaultsSafest Counties
r = +0.42 · moderate · n = 617
Plot
Total Violent CrimesMost Violent Counties
r = +0.42 · moderate · n = 617
Plot
Population
r = +0.40 · moderate · n = 960
Plot
Average Temperature (°F)Climate by County (1991–2020 Averages)
r = +0.36 · moderate · n = 959
Plot

Opposite directions

Places that have a higher Median Air Quality Index tend to score lower on these

Heating Degree Days per YearClimate by County (1991–2020 Averages)
r = −0.33 · moderate · n = 948
Plot
Adults Who Binge Drink (%)Health of Adults by County (CDC PLACES)
r = −0.19 · weak · n = 897
Plot
Presidential Margin (Republican minus Democratic, Points)Presidential Election Results by County, 2016–2024
r = −0.16 · weak · n = 954
Plot
Republican Vote Share (President, %)Presidential Election Results by County, 2016–2024
r = −0.15 · weak · n = 954
Plot
Adults with Depression (%)Health of Adults by County (CDC PLACES)
r = −0.11 · weak · n = 897
Plot
Land Area (mi²)
r = −0.11 · weak · n = 960
Plot

Quick answers

Which county has the highest Median Air Quality Index?: Riverside County, CA has the highest Median Air Quality Index in 2025, at 80, followed by San Bernardino County, CA (77) and Los Angeles County, CA (74).
Which county has the lowest Median Air Quality Index?: Karnes County, TX has the lowest Median Air Quality Index in 2025, at 6.
What is the median Median Air Quality Index across US counties?: The median is 40 across the 960 US counties with data in 2025.
Where does this air quality by county (epa) data come from?: Rankodex compiles it from World Population Review and the primary sources it cites: Air Quality Statistics by County - US Environmental Protection Agency.