Which county in Texas has the best air quality?

Based on 2024 EPA AQS data, Karnes County had the best air quality in Texas with a median AQI of 7 and 363 good-air days.

2024 monitoring year Public dataset EPA AQS

Texas Air Quality Rankings

Compiled by PlainEnviro Editorial, Environmental Data Editorial Team · July 13, 2026

County-level AQI rollup using EPA Air Quality System monitor records. Refreshed as new EPA AQS data lands.

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County-by-county air quality data for Texas based on EPA AQS annual AQI readings. Data covers 45 monitored counties for 2024.

Texas (2024): 45 counties monitored. State average median AQI: 42 (national average: 38.8). 66% of monitored days rated "Good." Most unhealthy air: Harris County (14 days above AQI 100).

Texas air quality on this page is drawn from the EPA Air Quality System (AQS), which aggregates daily readings from federal, state, tribal, and local monitors into annual summaries per county. The current dataset covers 45 Texas counties with at least ten days of valid AQI readings in 2024, out of the state's total monitored counties.

The state-average median AQI across those counties is 42, compared with a national average of 38.8 in the same reporting period. On average, 66% of monitored days fell into the "Good" AQI bucket (0–50). The heaviest burden of unhealthy days lands on Harris County (14 days above AQI 100), while Karnes County records the cleanest air with a median AQI of 7.

AQI values translate ambient concentrations of pollutants (ozone, PM2.5, PM10, NO₂, SO₂, CO) onto a single 0–500 scale with six health-based bands. A low median AQI reflects typical daily conditions; peak values matter separately because short-term exposure drives most acute health effects. Counties without monitors are not "clean" - they are simply unmeasured by EPA AQS. For site-specific exposure guidance, check AirNow.gov alongside the county detail links below.

Counties with Data

State Avg Median AQI

National Avg Median AQI

38.8

Avg Good Days %

66%

Which Texas counties have the worst air quality?

Ranked by median AQI (higher = worse). Click a county for full environmental data.

#	County	Median AQI	Good Days	Good %	Unhealthy Days	Peak AQI
1	El Paso	67	81	22%	12	431
2	Harris	61	50	14%	14	201
3	Cameron	61	99	27%	13	171
4	Dallas	55	129	35%	3	185
5	Montgomery	55	111	31%	1	166
6	Tarrant	54	130	36%	6	203
7	Hidalgo	54	150	41%	5	157
8	Mclennan	53	126	35%	0	133
9	Jefferson	53	137	37%	0	143
10	Bexar	52	174	48%	2	199
11	Travis	52	156	43%	0	141
12	Nueces	51	178	49%	1	153
13	Bowie	49	189	53%	0	97
14	Navarro	48	205	56%	0	129
15	Denton	47	210	57%	3	187
16	Kaufman	46	226	62%	0	147
17	Bell	46	226	62%	0	129
18	Webb	45	211	58%	0	129
19	Harrison	44	233	64%	3	263
20	Galveston	44	245	68%	2	159
21	Orange	44	238	65%	0	119
22	Atascosa	44	198	57%	0	116
23	Kleberg	43	204	58%	0	121
24	Randall	43	283	79%	0	108
25	Brewster	43	231	71%	0	112
26	Collin	40	283	78%	3	161
27	Hood	40	274	80%	1	154
28	Smith	39	314	87%	0	105
29	Johnson	39	286	82%	0	129
30	Brazos	39	232	66%	0	102
31	Hunt	37	324	90%	0	133
32	Gregg	37	322	89%	0	129
33	Brazoria	37	303	83%	1	164
34	Maverick	37	233	68%	0	100
35	Ellis	36	323	89%	0	101
36	Parker	36	299	86%	1	156
37	Ector	36	280	79%	0	88
38	Victoria	35	324	91%	0	105
39	Rockwall	34	315	93%	0	126
40	Polk	33	338	97%	0	93
41	Potter	29	294	88%	0	138
42	Culberson	26	99	89%	0	88
43	Lubbock	23	330	92%	0	91
44	Wilson	7	190	100%	0	34
45	Karnes	7	363	100%	0	33

Frequently Asked Questions

What is the air quality like in Texas?

In 2024, Texas had an average median AQI of 42 across 45 monitored counties, with 66% of monitored days rated "Good" (AQI 0–50). The national average median AQI is 38.8.

Which county in Texas has the worst air quality?

Based on 2024 EPA AQS data, Harris County had the most unhealthy air days in Texas - 14 days above AQI 100, with a median AQI of 61.

Explore More

National AQI Rankings → Texas Full Profile → Texas Water Quality →

About This Data

Air quality data is from the EPA Air Quality System (AQS), Annual AQI by County dataset. Counties with fewer than 10 monitored days are excluded. "Unhealthy days" counts days with AQI above 100 (Unhealthy for Sensitive Groups or worse). All data is for 2024.

Source: U.S. Environmental Protection Agency, Air Quality System (AQS) U.S. Environmental Protection Agency, Air Quality System (AQS)

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from the U.S. Environmental Protection Agency (EPA). See our methodology for details. Retrieved and formatted by PlainEnviro Editorial