Data / Rankings / Median Air Quality Index (US EPA) / Counties in Texas

Counties in Texas by median Air Quality Index (US EPA)

El Paso County had the highest median Air Quality Index (US EPA) of 45 counties in 2020, at 59. Karnes County had the lowest, at 6. The median was 42. Source: the U.S. Environmental Protection Agency.

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Highest59El Paso County
Lowest6Karnes County
Median4245 counties

Map of counties, 2020

Atascosa County: 38 indexBell County: 44 indexBexar County: 55 indexBowie County: 48 indexBrazoria County: 33 indexBrazos County: 40 indexBrewster County: 41 indexCameron County: 52 indexCollin County: 37 indexCulberson County: 46 indexDallas County: 46 indexDenton County: 44 indexEctor County: 36 indexEllis County: 45 indexEl Paso County: 59 indexGalveston County: 44 indexGregg County: 31 indexHarris County: 56 indexHarrison County: 40 indexHidalgo County: 44 indexHood County: 33 indexHunt County: 32 indexJefferson County: 46 indexJohnson County: 34 indexKarnes County: 6 indexKaufman County: 42 indexKleberg County: 46 indexLubbock County: 26 indexMcLennan County: 39 indexMaverick County: 36 indexMontgomery County: 44 indexNavarro County: 42 indexNueces County: 46 indexOrange County: 44 indexParker County: 35 indexPolk County: 31 indexPotter County: 26 indexRandall County: 42 indexRockwall County: 32 indexSmith County: 33 indexTarrant County: 52 indexTravis County: 51 indexVictoria County: 31 indexWebb County: 47 indexWilson County: 7 index
  • Under 32
  • 32 to 36
  • 36 to 42
  • 42 to 44
  • 44 to 47
  • 47 and over
  • No data
index, 2020. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2020

El Paso County: 59 indexEl Paso County59Harris County: 56 indexHarris County56Bexar County: 55 indexBexar County55Cameron County: 52 indexCameron County52Tarrant County: 52 indexTarrant County52Travis County: 51 indexTravis County51Bowie County: 48 indexBowie County48Webb County: 47 indexWebb County47Culberson County: 46 indexCulberson County46Dallas County: 46 indexDallas County46Jefferson County: 46 indexJefferson County46Kleberg County: 46 indexKleberg County46Nueces County: 46 indexNueces County46Ellis County: 45 indexEllis County45Bell County: 44 indexBell County44Denton County: 44 indexDenton County44Galveston County: 44 indexGalveston County44Hidalgo County: 44 indexHidalgo County44Montgomery County: 44 indexMontgomery County44Orange County: 44 indexOrange County44Kaufman County: 42 indexKaufman County42Navarro County: 42 indexNavarro County42Randall County: 42 indexRandall County42Brewster County: 41 indexBrewster County41Brazos County: 40 indexBrazos County40Harrison County: 40 indexHarrison County40McLennan County: 39 indexMcLennan County39Atascosa County: 38 indexAtascosa County38Collin County: 37 indexCollin County37Ector County: 36 indexEctor County36Maverick County: 36 indexMaverick County36Parker County: 35 indexParker County35Johnson County: 34 indexJohnson County34Brazoria County: 33 indexBrazoria County33Hood County: 33 indexHood County33Smith County: 33 indexSmith County33Hunt County: 32 indexHunt County32Rockwall County: 32 indexRockwall County32Gregg County: 31 indexGregg County31Polk County: 31 indexPolk County31Victoria County: 31 indexVictoria County31Lubbock County: 26 indexLubbock County26Potter County: 26 indexPotter County26Wilson County: 7 indexWilson County7Karnes County: 6 indexKarnes County6El Paso County: 59 indexEl Paso County59Harris County: 56 indexHarris County56Bexar County: 55 indexBexar County55Cameron County: 52 indexCameron County52Tarrant County: 52 indexTarrant County52Travis County: 51 indexTravis County51Bowie County: 48 indexBowie County48Webb County: 47 indexWebb County47Culberson County: 46 indexCulberson County46Dallas County: 46 indexDallas County46Jefferson County: 46 indexJefferson County46Kleberg County: 46 indexKleberg County46Nueces County: 46 indexNueces County46Ellis County: 45 indexEllis County45Bell County: 44 indexBell County44Denton County: 44 indexDenton County44Galveston County: 44 indexGalveston County44Hidalgo County: 44 indexHidalgo County44Montgomery County: 44 indexMontgomery County44Orange County: 44 indexOrange County44Kaufman County: 42 indexKaufman County42Navarro County: 42 indexNavarro County42Randall County: 42 indexRandall County42Brewster County: 41 indexBrewster County41Brazos County: 40 indexBrazos County40Harrison County: 40 indexHarrison County40McLennan County: 39 indexMcLennan County39Atascosa County: 38 indexAtascosa County38Collin County: 37 indexCollin County37Ector County: 36 indexEctor County36Maverick County: 36 indexMaverick County36Parker County: 35 indexParker County35Johnson County: 34 indexJohnson County34Brazoria County: 33 indexBrazoria County33Hood County: 33 indexHood County33Smith County: 33 indexSmith County33Hunt County: 32 indexHunt County32Rockwall County: 32 indexRockwall County32Gregg County: 31 indexGregg County31Polk County: 31 indexPolk County31Victoria County: 31 indexVictoria County31Lubbock County: 26 indexLubbock County26Potter County: 26 indexPotter County26Wilson County: 7 indexWilson County7Karnes County: 6 indexKarnes County6
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2020
index		Change on 2019
1El Paso County59+2
2Harris County560
3Bexar County550
4Cameron County520
4Tarrant County52+1
6Travis County51-1
7Bowie County48-3
8Webb County47-3
9Culberson County46+10
9Dallas County46-6
9Jefferson County46-3
9Kleberg County46+5
9Nueces County46-3
14Ellis County45+1
15Bell County44-1
15Denton County440
15Galveston County44+1
15Hidalgo County44-6
15Montgomery County440
15Orange County440
21Kaufman County420
21Navarro County420
21Randall County42+1
24Brewster County41-1
25Brazos County40n/a
25Harrison County40-4
27McLennan County390
28Atascosa County38n/a
29Collin County37-3
30Ector County36-2
30Maverick County36+2
32Parker County35-2
33Johnson County34-4
34Brazoria County330
34Hood County33-2
34Smith County33-3
37Hunt County32-3
37Rockwall County32-2
39Gregg County31-4
39Polk County310
39Victoria County310
42Lubbock County26-8
42Potter County26+1
44Wilson County7n/a
45Karnes County6n/a

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 18 counties with data in other periods have no value for 2020 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: median daily AQI (Counties in Texas by median Air Quality Index (US EPA), 2020) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: median daily AQI, Counties in Texas by median Air Quality Index (US EPA), 2020. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Texas by median Air Quality Index (US EPA), 2020. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Texas by median Air Quality Index (US EPA), 2020 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_texas_by_2020,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Texas by median Air Quality Index (US EPA), 2020}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: median daily AQI: Counties in Texas by median Air Quality Index (US EPA), 2020
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2020.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Texas by median Air Quality Index (US EPA) using official data, and cite the source.
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Questions

Which county has the highest median Air Quality Index (US EPA)?

El Paso County, with 59 in 2020, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Karnes County, with 6 in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12. 18 counties have no value for 2020 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Texas: more rankings