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)

Polk County had the highest share of days with good air quality (US EPA AQI) of 41 counties in 2019, at 97.1%. Harris County had the lowest, at 24.9%. The median was 71.5%. Source: EPA.

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Highest97.1Polk County
Lowest24.9Harris County
Median71.541 counties

Map of counties, 2019

Bell County: 64.9 %Bexar County: 32.1 %Bowie County: 49 %Brazoria County: 89 %Brewster County: 76.8 %Cameron County: 47.1 %Collin County: 84.7 %Culberson County: 86.9 %Dallas County: 42.7 %Denton County: 65.5 %Ector County: 70.9 %Ellis County: 68.5 %El Paso County: 27.4 %Galveston County: 68.2 %Gregg County: 90.6 %Harris County: 24.9 %Harrison County: 67.6 %Hidalgo County: 50.4 %Hood County: 91 %Hunt County: 94.8 %Jefferson County: 53.2 %Johnson County: 84.7 %Kaufman County: 76.2 %Kleberg County: 64.1 %Lubbock County: 85.2 %McLennan County: 85.8 %Maverick County: 72.6 %Montgomery County: 71.5 %Navarro County: 76 %Nueces County: 54.2 %Orange County: 63.8 %Parker County: 87.3 %Polk County: 97.1 %Potter County: 89.4 %Randall County: 79.1 %Rockwall County: 94.4 %Smith County: 89.6 %Tarrant County: 48.2 %Travis County: 46.3 %Victoria County: 93.5 %Webb County: 51.2 %
  • Under 49
  • 49 to 64
  • 64 to 72
  • 72 to 85
  • 85 to 89
  • 89 and over
  • No data
%, 2019. 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, 2019

Polk County: 97.1 %Polk County97.1Hunt County: 94.8 %Hunt County94.8Rockwall County: 94.4 %Rockwall County94.4Victoria County: 93.5 %Victoria County93.5Hood County: 91 %Hood County91Gregg County: 90.6 %Gregg County90.6Smith County: 89.6 %Smith County89.6Potter County: 89.4 %Potter County89.4Brazoria County: 89 %Brazoria County89Parker County: 87.3 %Parker County87.3Culberson County: 86.9 %Culberson County86.9McLennan County: 85.8 %McLennan County85.8Lubbock County: 85.2 %Lubbock County85.2Collin County: 84.7 %Collin County84.7Johnson County: 84.7 %Johnson County84.7Randall County: 79.1 %Randall County79.1Brewster County: 76.8 %Brewster County76.8Kaufman County: 76.2 %Kaufman County76.2Navarro County: 76 %Navarro County76Maverick County: 72.6 %Maverick County72.6Montgomery County: 71.5 %Montgomery County71.5Ector County: 70.9 %Ector County70.9Ellis County: 68.5 %Ellis County68.5Galveston County: 68.2 %Galveston County68.2Harrison County: 67.6 %Harrison County67.6Denton County: 65.5 %Denton County65.5Bell County: 64.9 %Bell County64.9Kleberg County: 64.1 %Kleberg County64.1Orange County: 63.8 %Orange County63.8Nueces County: 54.2 %Nueces County54.2Jefferson County: 53.2 %Jefferson County53.2Webb County: 51.2 %Webb County51.2Hidalgo County: 50.4 %Hidalgo County50.4Bowie County: 49 %Bowie County49Tarrant County: 48.2 %Tarrant County48.2Cameron County: 47.1 %Cameron County47.1Travis County: 46.3 %Travis County46.3Dallas County: 42.7 %Dallas County42.7Bexar County: 32.1 %Bexar County32.1El Paso County: 27.4 %El Paso County27.4Harris County: 24.9 %Harris County24.9Polk County: 97.1 %Polk County97.1Hunt County: 94.8 %Hunt County94.8Rockwall County: 94.4 %Rockwall County94.4Victoria County: 93.5 %Victoria County93.5Hood County: 91 %Hood County91Gregg County: 90.6 %Gregg County90.6Smith County: 89.6 %Smith County89.6Potter County: 89.4 %Potter County89.4Brazoria County: 89 %Brazoria County89Parker County: 87.3 %Parker County87.3Culberson County: 86.9 %Culberson County86.9McLennan County: 85.8 %McLennan County85.8Lubbock County: 85.2 %Lubbock County85.2Collin County: 84.7 %Collin County84.7Johnson County: 84.7 %Johnson County84.7Randall County: 79.1 %Randall County79.1Brewster County: 76.8 %Brewster County76.8Kaufman County: 76.2 %Kaufman County76.2Navarro County: 76 %Navarro County76Maverick County: 72.6 %Maverick County72.6Montgomery County: 71.5 %Montgomery County71.5Ector County: 70.9 %Ector County70.9Ellis County: 68.5 %Ellis County68.5Galveston County: 68.2 %Galveston County68.2Harrison County: 67.6 %Harrison County67.6Denton County: 65.5 %Denton County65.5Bell County: 64.9 %Bell County64.9Kleberg County: 64.1 %Kleberg County64.1Orange County: 63.8 %Orange County63.8Nueces County: 54.2 %Nueces County54.2Jefferson County: 53.2 %Jefferson County53.2Webb County: 51.2 %Webb County51.2Hidalgo County: 50.4 %Hidalgo County50.4Bowie County: 49 %Bowie County49Tarrant County: 48.2 %Tarrant County48.2Cameron County: 47.1 %Cameron County47.1Travis County: 46.3 %Travis County46.3Dallas County: 42.7 %Dallas County42.7Bexar County: 32.1 %Bexar County32.1El Paso County: 27.4 %El Paso County27.4Harris County: 24.9 %Harris County24.9
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2019 (%)Change on 2018
1Polk County97.1+2 pts
2Hunt County94.8+4.7 pts
3Rockwall County94.4+2 pts
4Victoria County93.5-3.3 pts
5Hood County91+3.7 pts
6Gregg County90.6+0.2 pts
7Smith County89.6+0.6 pts
8Potter County89.4-0.1 pts
9Brazoria County89-1.1 pts
10Parker County87.3-1.6 pts
11Culberson County86.9+9.5 pts
12McLennan County85.8+6.3 pts
13Lubbock County85.2+6.3 pts
14Collin County84.7+2.7 pts
14Johnson County84.7-0.6 pts
16Randall County79.1+5.6 pts
17Brewster County76.8+1.3 pts
18Kaufman County76.2+2.8 pts
19Navarro County76+2.9 pts
20Maverick County72.6-1.1 pts
21Montgomery County71.5+8.2 pts
22Ector County70.9+2.9 pts
23Ellis County68.5+5.8 pts
24Galveston County68.2-15.9 pts
25Harrison County67.6-4.7 pts
26Denton County65.5-4.1 pts
27Bell County64.9-22.8 pts
28Kleberg County64.1+9.1 pts
29Orange County63.8+16.4 pts
30Nueces County54.2-4.4 pts
31Jefferson County53.2+9.1 pts
32Webb County51.2-9.5 pts
33Hidalgo County50.4+2.7 pts
34Bowie County49-9.9 pts
35Tarrant County48.2+5.5 pts
36Cameron County47.1-1.7 pts
37Travis County46.3+0.3 pts
38Dallas County42.7-4.1 pts
39Bexar County32.1-19.1 pts
40El Paso County27.4+2.5 pts
41Harris County24.9-3 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. 22 counties with data in other periods have no value for 2019 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), 2019) [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), 2019. 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=2019. 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), 2019. 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=2019.

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), 2019 [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=2019 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_texas_by_2019,
  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), 2019}},
  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=2019. 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), 2019
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=2019
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/texas-counties?period=2019.
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)?

Polk County, with 97.1% in 2019, according to EPA.

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

Harris County, with 24.9% in 2019.

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. 22 counties have no value for 2019 and are not ranked.

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

Counties in Texas: more rankings