Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in Texas

Counties in Texas by share of days with good air quality (US EPA AQI)

Karnes County had the highest share of days with good air quality (US EPA AQI) of 45 counties in 2020, at 100%. El Paso County had the lowest, at 26%. The median was 70.2%. Source: EPA.

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Highest100Karnes County
Lowest26El Paso County
Median70.245 counties

Map of counties, 2020

Atascosa County: 69.6 %Bell County: 64.5 %Bexar County: 32.5 %Bowie County: 53.9 %Brazoria County: 89.9 %Brazos County: 69.3 %Brewster County: 87.2 %Cameron County: 43.2 %Collin County: 86.8 %Culberson County: 62.2 %Dallas County: 59.6 %Denton County: 66.9 %Ector County: 78.3 %Ellis County: 65.3 %El Paso County: 26 %Galveston County: 66.1 %Gregg County: 98.3 %Harris County: 29.8 %Harrison County: 72.7 %Hidalgo County: 60.7 %Hood County: 92.4 %Hunt County: 95.9 %Jefferson County: 60.3 %Johnson County: 91.7 %Karnes County: 100 %Kaufman County: 71 %Kleberg County: 54.8 %Lubbock County: 88.4 %McLennan County: 80.3 %Maverick County: 73.2 %Montgomery County: 59.8 %Navarro County: 70.2 %Nueces County: 62 %Orange County: 61.6 %Parker County: 91.4 %Polk County: 97.5 %Potter County: 90 %Randall County: 77.6 %Rockwall County: 95 %Smith County: 96.2 %Tarrant County: 44.5 %Travis County: 49.7 %Victoria County: 93.6 %Webb County: 59.3 %Wilson County: 100 %
  • Under 56
  • 56 to 62
  • 62 to 70
  • 70 to 87
  • 87 to 93
  • 93 and over
  • No data
%, 2020. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2020

Karnes County: 100 %Karnes County100Wilson County: 100 %Wilson County100Gregg County: 98.3 %Gregg County98.3Polk County: 97.5 %Polk County97.5Smith County: 96.2 %Smith County96.2Hunt County: 95.9 %Hunt County95.9Rockwall County: 95 %Rockwall County95Victoria County: 93.6 %Victoria County93.6Hood County: 92.4 %Hood County92.4Johnson County: 91.7 %Johnson County91.7Parker County: 91.4 %Parker County91.4Potter County: 90 %Potter County90Brazoria County: 89.9 %Brazoria County89.9Lubbock County: 88.4 %Lubbock County88.4Brewster County: 87.2 %Brewster County87.2Collin County: 86.8 %Collin County86.8McLennan County: 80.3 %McLennan County80.3Ector County: 78.3 %Ector County78.3Randall County: 77.6 %Randall County77.6Maverick County: 73.2 %Maverick County73.2Harrison County: 72.7 %Harrison County72.7Kaufman County: 71 %Kaufman County71Navarro County: 70.2 %Navarro County70.2Atascosa County: 69.6 %Atascosa County69.6Brazos County: 69.3 %Brazos County69.3Denton County: 66.9 %Denton County66.9Galveston County: 66.1 %Galveston County66.1Ellis County: 65.3 %Ellis County65.3Bell County: 64.5 %Bell County64.5Culberson County: 62.2 %Culberson County62.2Nueces County: 62 %Nueces County62Orange County: 61.6 %Orange County61.6Hidalgo County: 60.7 %Hidalgo County60.7Jefferson County: 60.3 %Jefferson County60.3Montgomery County: 59.8 %Montgomery County59.8Dallas County: 59.6 %Dallas County59.6Webb County: 59.3 %Webb County59.3Kleberg County: 54.8 %Kleberg County54.8Bowie County: 53.9 %Bowie County53.9Travis County: 49.7 %Travis County49.7Tarrant County: 44.5 %Tarrant County44.5Cameron County: 43.2 %Cameron County43.2Bexar County: 32.5 %Bexar County32.5Harris County: 29.8 %Harris County29.8El Paso County: 26 %El Paso County26Karnes County: 100 %Karnes County100Wilson County: 100 %Wilson County100Gregg County: 98.3 %Gregg County98.3Polk County: 97.5 %Polk County97.5Smith County: 96.2 %Smith County96.2Hunt County: 95.9 %Hunt County95.9Rockwall County: 95 %Rockwall County95Victoria County: 93.6 %Victoria County93.6Hood County: 92.4 %Hood County92.4Johnson County: 91.7 %Johnson County91.7Parker County: 91.4 %Parker County91.4Potter County: 90 %Potter County90Brazoria County: 89.9 %Brazoria County89.9Lubbock County: 88.4 %Lubbock County88.4Brewster County: 87.2 %Brewster County87.2Collin County: 86.8 %Collin County86.8McLennan County: 80.3 %McLennan County80.3Ector County: 78.3 %Ector County78.3Randall County: 77.6 %Randall County77.6Maverick County: 73.2 %Maverick County73.2Harrison County: 72.7 %Harrison County72.7Kaufman County: 71 %Kaufman County71Navarro County: 70.2 %Navarro County70.2Atascosa County: 69.6 %Atascosa County69.6Brazos County: 69.3 %Brazos County69.3Denton County: 66.9 %Denton County66.9Galveston County: 66.1 %Galveston County66.1Ellis County: 65.3 %Ellis County65.3Bell County: 64.5 %Bell County64.5Culberson County: 62.2 %Culberson County62.2Nueces County: 62 %Nueces County62Orange County: 61.6 %Orange County61.6Hidalgo County: 60.7 %Hidalgo County60.7Jefferson County: 60.3 %Jefferson County60.3Montgomery County: 59.8 %Montgomery County59.8Dallas County: 59.6 %Dallas County59.6Webb County: 59.3 %Webb County59.3Kleberg County: 54.8 %Kleberg County54.8Bowie County: 53.9 %Bowie County53.9Travis County: 49.7 %Travis County49.7Tarrant County: 44.5 %Tarrant County44.5Cameron County: 43.2 %Cameron County43.2Bexar County: 32.5 %Bexar County32.5Harris County: 29.8 %Harris County29.8El Paso County: 26 %El Paso County26
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2020 (%)Change on 2019
1Karnes County100n/a
1Wilson County100n/a
3Gregg County98.3+7.7 pts
4Polk County97.5+0.4 pts
5Smith County96.2+6.6 pts
6Hunt County95.9+1.1 pts
7Rockwall County95+0.6 pts
8Victoria County93.6+0.1 pts
9Hood County92.4+1.4 pts
10Johnson County91.7+7 pts
11Parker County91.4+4.1 pts
12Potter County90+0.6 pts
13Brazoria County89.9+0.9 pts
14Lubbock County88.4+3.2 pts
15Brewster County87.2+10.4 pts
16Collin County86.8+2.1 pts
17McLennan County80.3-5.5 pts
18Ector County78.3+7.4 pts
19Randall County77.6-1.5 pts
20Maverick County73.2+0.6 pts
21Harrison County72.7+5.1 pts
22Kaufman County71-5.2 pts
23Navarro County70.2-5.8 pts
24Atascosa County69.6n/a
25Brazos County69.3n/a
26Denton County66.9+1.4 pts
27Galveston County66.1-2.1 pts
28Ellis County65.3-3.2 pts
29Bell County64.5-0.4 pts
30Culberson County62.2-24.7 pts
31Nueces County62+7.8 pts
32Orange County61.6-2.2 pts
33Hidalgo County60.7+10.3 pts
34Jefferson County60.3+7.1 pts
35Montgomery County59.8-11.7 pts
36Dallas County59.6+16.9 pts
37Webb County59.3+8.1 pts
38Kleberg County54.8-9.3 pts
39Bowie County53.9+4.9 pts
40Travis County49.7+3.4 pts
41Tarrant County44.5-3.7 pts
42Cameron County43.2-3.9 pts
43Bexar County32.5+0.4 pts
44Harris County29.8+4.9 pts
45El Paso County26-1.4 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

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: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts (Counties in Texas by share of days with good air quality (US EPA AQI), 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: good days as a share of days with an AQI, calculated with stored counts, Counties in Texas by share of days with good air quality (US EPA AQI), 2020. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/texas-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in Texas by share of days with good air quality (US EPA AQI), 2020. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/texas-counties?period=2020.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Texas by share of days with good air quality (US EPA AQI), 2020 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/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: good days as a share of days with an AQI, calculated with stored counts: Counties in Texas by share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/texas-counties?period=2020. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts: Counties in Texas by share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/texas-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/texas-counties?period=2020.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Texas by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Karnes County, with 100% in 2020, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

El Paso County, with 26% 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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 18 counties have no value for 2020 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in Texas: more rankings