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 2018, at 59. Victoria County had the lowest, at 28. The median was 41. Source: the U.S. Environmental Protection Agency.

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Highest59El Paso County
Lowest28Victoria County
Median4142 counties

Map of counties, 2018

Bell County: 36 indexBexar County: 49 indexBowie County: 47 indexBrazoria County: 31 indexBrewster County: 40 indexCameron County: 51 indexCollin County: 37 indexCulberson County: 31 indexDallas County: 52 indexDenton County: 42 indexEctor County: 40 indexEllis County: 45 indexEl Paso County: 59 indexFayette County: 34 indexGalveston County: 34 indexGregg County: 32 indexHarris County: 56 indexHarrison County: 41 indexHidalgo County: 51 indexHood County: 33 indexHunt County: 32 indexJefferson County: 53 indexJohnson County: 35 indexKaufman County: 41 indexKleberg County: 47 indexLubbock County: 33 indexMcLennan County: 38 indexMaverick County: 37 indexMontgomery County: 44 indexNavarro County: 41 indexNueces County: 44 indexOrange County: 52 indexParker County: 35 indexPolk County: 31 indexPotter County: 30 indexRandall County: 43 indexRockwall County: 31 indexSmith County: 33 indexTarrant County: 53 indexTravis County: 52 indexVictoria County: 28 indexWebb County: 44 index
  • Under 32
  • 32 to 35
  • 35 to 41
  • 41 to 44
  • 44 to 51
  • 51 and over
  • No data
index, 2018. 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, 2018

El Paso County: 59 indexEl Paso County59Harris County: 56 indexHarris County56Jefferson County: 53 indexJefferson County53Tarrant County: 53 indexTarrant County53Dallas County: 52 indexDallas County52Orange County: 52 indexOrange County52Travis County: 52 indexTravis County52Cameron County: 51 indexCameron County51Hidalgo County: 51 indexHidalgo County51Bexar County: 49 indexBexar County49Bowie County: 47 indexBowie County47Kleberg County: 47 indexKleberg County47Ellis County: 45 indexEllis County45Montgomery County: 44 indexMontgomery County44Nueces County: 44 indexNueces County44Webb County: 44 indexWebb County44Randall County: 43 indexRandall County43Denton County: 42 indexDenton County42Harrison County: 41 indexHarrison County41Kaufman County: 41 indexKaufman County41Navarro County: 41 indexNavarro County41Brewster County: 40 indexBrewster County40Ector County: 40 indexEctor County40McLennan County: 38 indexMcLennan County38Collin County: 37 indexCollin County37Maverick County: 37 indexMaverick County37Bell County: 36 indexBell County36Johnson County: 35 indexJohnson County35Parker County: 35 indexParker County35Fayette County: 34 indexFayette County34Galveston County: 34 indexGalveston County34Hood County: 33 indexHood County33Lubbock County: 33 indexLubbock County33Smith County: 33 indexSmith County33Gregg County: 32 indexGregg County32Hunt County: 32 indexHunt County32Brazoria County: 31 indexBrazoria County31Culberson County: 31 indexCulberson County31Polk County: 31 indexPolk County31Rockwall County: 31 indexRockwall County31Potter County: 30 indexPotter County30Victoria County: 28 indexVictoria County28El Paso County: 59 indexEl Paso County59Harris County: 56 indexHarris County56Jefferson County: 53 indexJefferson County53Tarrant County: 53 indexTarrant County53Dallas County: 52 indexDallas County52Orange County: 52 indexOrange County52Travis County: 52 indexTravis County52Cameron County: 51 indexCameron County51Hidalgo County: 51 indexHidalgo County51Bexar County: 49 indexBexar County49Bowie County: 47 indexBowie County47Kleberg County: 47 indexKleberg County47Ellis County: 45 indexEllis County45Montgomery County: 44 indexMontgomery County44Nueces County: 44 indexNueces County44Webb County: 44 indexWebb County44Randall County: 43 indexRandall County43Denton County: 42 indexDenton County42Harrison County: 41 indexHarrison County41Kaufman County: 41 indexKaufman County41Navarro County: 41 indexNavarro County41Brewster County: 40 indexBrewster County40Ector County: 40 indexEctor County40McLennan County: 38 indexMcLennan County38Collin County: 37 indexCollin County37Maverick County: 37 indexMaverick County37Bell County: 36 indexBell County36Johnson County: 35 indexJohnson County35Parker County: 35 indexParker County35Fayette County: 34 indexFayette County34Galveston County: 34 indexGalveston County34Hood County: 33 indexHood County33Lubbock County: 33 indexLubbock County33Smith County: 33 indexSmith County33Gregg County: 32 indexGregg County32Hunt County: 32 indexHunt County32Brazoria County: 31 indexBrazoria County31Culberson County: 31 indexCulberson County31Polk County: 31 indexPolk County31Rockwall County: 31 indexRockwall County31Potter County: 30 indexPotter County30Victoria County: 28 indexVictoria County28
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2018
index		Change on 2017
1El Paso County59+3
2Harris County56+2
3Jefferson County53+6
3Tarrant County53+2
5Dallas County520
5Orange County52+9
5Travis County52+2
8Cameron County51+9
8Hidalgo County51+4
10Bexar County49-1
11Bowie County47-2
11Kleberg County47+4
13Ellis County45-5
14Montgomery County44-2
14Nueces County44-1
14Webb County44-5
17Randall County430
18Denton County42-4
19Harrison County41-5
19Kaufman County41-3
19Navarro County41-5
22Brewster County40-2
22Ector County40+5
24McLennan County38-1
25Collin County37-2
25Maverick County37-2
27Bell County36-4
28Johnson County35-6
28Parker County35-2
30Fayette County34+1
30Galveston County34-7
32Hood County33-3
32Lubbock County330
32Smith County33-4
35Gregg County32-3
35Hunt County32-3
37Brazoria County31-6
37Culberson County31+9
37Polk County310
37Rockwall County31-4
41Potter County30+2
42Victoria County28-5

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 2018 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), 2018) [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), 2018. 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=2018. 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), 2018. 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=2018.

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), 2018 [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=2018 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_texas_by_2018,
  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), 2018}},
  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=2018. 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), 2018
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=2018
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/texas-counties?period=2018.
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 2018, according to the U.S. Environmental Protection Agency.

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

Victoria County, with 28 in 2018.

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 2018 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Texas: more rankings