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 42 counties in 2017, at 56. Culberson County had the lowest, at 22. The median was 42. Source: the U.S. Environmental Protection Agency.

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Highest56El Paso County
Lowest22Culberson County
Median4242 counties

Map of counties, 2017

Bell County: 40 indexBexar County: 50 indexBowie County: 49 indexBrazoria County: 37 indexBrewster County: 42 indexCameron County: 42 indexCollin County: 39 indexCulberson County: 22 indexDallas County: 52 indexDenton County: 46 indexEctor County: 35 indexEllis County: 50 indexEl Paso County: 56 indexFayette County: 33 indexGalveston County: 41 indexGregg County: 35 indexHarris County: 54 indexHarrison County: 46 indexHidalgo County: 47 indexHood County: 36 indexHunt County: 35 indexJefferson County: 47 indexJohnson County: 41 indexKaufman County: 44 indexKleberg County: 43 indexLubbock County: 33 indexMcLennan County: 39 indexMaverick County: 39 indexMontgomery County: 46 indexNavarro County: 46 indexNueces County: 45 indexOrange County: 43 indexParker County: 37 indexPolk County: 31 indexPotter County: 28 indexRandall County: 43 indexRockwall County: 35 indexSmith County: 37 indexTarrant County: 51 indexTravis County: 50 indexVictoria County: 33 indexWebb County: 49 index
  • Under 35
  • 35 to 38
  • 38 to 42
  • 42 to 46
  • 46 to 49
  • 49 and over
  • No data
index, 2017. 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, 2017

El Paso County: 56 indexEl Paso County56Harris County: 54 indexHarris County54Dallas County: 52 indexDallas County52Tarrant County: 51 indexTarrant County51Bexar County: 50 indexBexar County50Ellis County: 50 indexEllis County50Travis County: 50 indexTravis County50Bowie County: 49 indexBowie County49Webb County: 49 indexWebb County49Hidalgo County: 47 indexHidalgo County47Jefferson County: 47 indexJefferson County47Denton County: 46 indexDenton County46Harrison County: 46 indexHarrison County46Montgomery County: 46 indexMontgomery County46Navarro County: 46 indexNavarro County46Nueces County: 45 indexNueces County45Kaufman County: 44 indexKaufman County44Kleberg County: 43 indexKleberg County43Orange County: 43 indexOrange County43Randall County: 43 indexRandall County43Brewster County: 42 indexBrewster County42Cameron County: 42 indexCameron County42Galveston County: 41 indexGalveston County41Johnson County: 41 indexJohnson County41Bell County: 40 indexBell County40Collin County: 39 indexCollin County39Maverick County: 39 indexMaverick County39McLennan County: 39 indexMcLennan County39Brazoria County: 37 indexBrazoria County37Parker County: 37 indexParker County37Smith County: 37 indexSmith County37Hood County: 36 indexHood County36Ector County: 35 indexEctor County35Gregg County: 35 indexGregg County35Hunt County: 35 indexHunt County35Rockwall County: 35 indexRockwall County35Fayette County: 33 indexFayette County33Lubbock County: 33 indexLubbock County33Victoria County: 33 indexVictoria County33Polk County: 31 indexPolk County31Potter County: 28 indexPotter County28Culberson County: 22 indexCulberson County22El Paso County: 56 indexEl Paso County56Harris County: 54 indexHarris County54Dallas County: 52 indexDallas County52Tarrant County: 51 indexTarrant County51Bexar County: 50 indexBexar County50Ellis County: 50 indexEllis County50Travis County: 50 indexTravis County50Bowie County: 49 indexBowie County49Webb County: 49 indexWebb County49Hidalgo County: 47 indexHidalgo County47Jefferson County: 47 indexJefferson County47Denton County: 46 indexDenton County46Harrison County: 46 indexHarrison County46Montgomery County: 46 indexMontgomery County46Navarro County: 46 indexNavarro County46Nueces County: 45 indexNueces County45Kaufman County: 44 indexKaufman County44Kleberg County: 43 indexKleberg County43Orange County: 43 indexOrange County43Randall County: 43 indexRandall County43Brewster County: 42 indexBrewster County42Cameron County: 42 indexCameron County42Galveston County: 41 indexGalveston County41Johnson County: 41 indexJohnson County41Bell County: 40 indexBell County40Collin County: 39 indexCollin County39Maverick County: 39 indexMaverick County39McLennan County: 39 indexMcLennan County39Brazoria County: 37 indexBrazoria County37Parker County: 37 indexParker County37Smith County: 37 indexSmith County37Hood County: 36 indexHood County36Ector County: 35 indexEctor County35Gregg County: 35 indexGregg County35Hunt County: 35 indexHunt County35Rockwall County: 35 indexRockwall County35Fayette County: 33 indexFayette County33Lubbock County: 33 indexLubbock County33Victoria County: 33 indexVictoria County33Polk County: 31 indexPolk County31Potter County: 28 indexPotter County28Culberson County: 22 indexCulberson County22
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2017
index		Change on 2016
1El Paso County56+1
2Harris County54-1
3Dallas County52+2
4Tarrant County51+3
5Bexar County50+1
5Ellis County50+4
5Travis County50+3
8Bowie County49+1
8Webb County49+3
10Hidalgo County47+4
10Jefferson County47+2
12Denton County46+2
12Harrison County46+4
12Montgomery County46-3
12Navarro County46+3
16Nueces County45+5
17Kaufman County44+2
18Kleberg County43+6
18Orange County43+4
18Randall County43+2
21Brewster County42+1
21Cameron County42-3
23Galveston County41-3
23Johnson County41+1
25Bell County40+2
26Collin County39+2
26Maverick County39+3
26McLennan County39+2
29Brazoria County37+1
29Parker County370
29Smith County370
32Hood County36+1
33Ector County35-1
33Gregg County35-1
33Hunt County350
33Rockwall County350
37Fayette County33-1
37Lubbock County33+5
37Victoria County330
40Polk County31-1
41Potter County280
42Culberson County22+3

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. 21 counties with data in other periods have no value for 2017 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), 2017) [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), 2017. 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=2017. 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), 2017. 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=2017.

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), 2017 [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=2017 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_texas_by_2017,
  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), 2017}},
  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=2017. 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), 2017
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=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2017.
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 56 in 2017, according to the U.S. Environmental Protection Agency.

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

Culberson County, with 22 in 2017.

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. 21 counties have no value for 2017 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Texas: more rankings