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 42 counties in 2017, at 97.4%. Harris County had the lowest, at 29.3%. The median was 73.8%. Source: EPA.

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Highest97.4Polk County
Lowest29.3Harris County
Median73.842 counties

Map of counties, 2017

Bell County: 83 %Bexar County: 51.2 %Bowie County: 52.2 %Brazoria County: 85.7 %Brewster County: 79 %Cameron County: 71 %Collin County: 86.2 %Culberson County: 94 %Dallas County: 44.1 %Denton County: 65.2 %Ector County: 82.9 %Ellis County: 50.1 %El Paso County: 32.9 %Fayette County: 85.8 %Galveston County: 74.4 %Gregg County: 93.1 %Harris County: 29.3 %Harrison County: 60.1 %Hidalgo County: 59.7 %Hood County: 90.8 %Hunt County: 94 %Jefferson County: 58.4 %Johnson County: 80.9 %Kaufman County: 65.2 %Kleberg County: 62.5 %Lubbock County: 84.7 %McLennan County: 86 %Maverick County: 73.2 %Montgomery County: 62.5 %Navarro County: 63.8 %Nueces County: 60.8 %Orange County: 62.3 %Parker County: 90.8 %Polk County: 97.4 %Potter County: 92.2 %Randall County: 78.1 %Rockwall County: 92.2 %Smith County: 92.3 %Tarrant County: 48.5 %Travis County: 50.7 %Victoria County: 93.3 %Webb County: 53.1 %
  • Under 52
  • 52 to 62
  • 62 to 74
  • 74 to 85
  • 85 to 92
  • 92 and over
  • No data
%, 2017. 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, 2017

Polk County: 97.4 %Polk County97.4Culberson County: 94 %Culberson County94Hunt County: 94 %Hunt County94Victoria County: 93.3 %Victoria County93.3Gregg County: 93.1 %Gregg County93.1Smith County: 92.3 %Smith County92.3Potter County: 92.2 %Potter County92.2Rockwall County: 92.2 %Rockwall County92.2Hood County: 90.8 %Hood County90.8Parker County: 90.8 %Parker County90.8Collin County: 86.2 %Collin County86.2McLennan County: 86 %McLennan County86Fayette County: 85.8 %Fayette County85.8Brazoria County: 85.7 %Brazoria County85.7Lubbock County: 84.7 %Lubbock County84.7Bell County: 83 %Bell County83Ector County: 82.9 %Ector County82.9Johnson County: 80.9 %Johnson County80.9Brewster County: 79 %Brewster County79Randall County: 78.1 %Randall County78.1Galveston County: 74.4 %Galveston County74.4Maverick County: 73.2 %Maverick County73.2Cameron County: 71 %Cameron County71Denton County: 65.2 %Denton County65.2Kaufman County: 65.2 %Kaufman County65.2Navarro County: 63.8 %Navarro County63.8Kleberg County: 62.5 %Kleberg County62.5Montgomery County: 62.5 %Montgomery County62.5Orange County: 62.3 %Orange County62.3Nueces County: 60.8 %Nueces County60.8Harrison County: 60.1 %Harrison County60.1Hidalgo County: 59.7 %Hidalgo County59.7Jefferson County: 58.4 %Jefferson County58.4Webb County: 53.1 %Webb County53.1Bowie County: 52.2 %Bowie County52.2Bexar County: 51.2 %Bexar County51.2Travis County: 50.7 %Travis County50.7Ellis County: 50.1 %Ellis County50.1Tarrant County: 48.5 %Tarrant County48.5Dallas County: 44.1 %Dallas County44.1El Paso County: 32.9 %El Paso County32.9Harris County: 29.3 %Harris County29.3Polk County: 97.4 %Polk County97.4Culberson County: 94 %Culberson County94Hunt County: 94 %Hunt County94Victoria County: 93.3 %Victoria County93.3Gregg County: 93.1 %Gregg County93.1Smith County: 92.3 %Smith County92.3Potter County: 92.2 %Potter County92.2Rockwall County: 92.2 %Rockwall County92.2Hood County: 90.8 %Hood County90.8Parker County: 90.8 %Parker County90.8Collin County: 86.2 %Collin County86.2McLennan County: 86 %McLennan County86Fayette County: 85.8 %Fayette County85.8Brazoria County: 85.7 %Brazoria County85.7Lubbock County: 84.7 %Lubbock County84.7Bell County: 83 %Bell County83Ector County: 82.9 %Ector County82.9Johnson County: 80.9 %Johnson County80.9Brewster County: 79 %Brewster County79Randall County: 78.1 %Randall County78.1Galveston County: 74.4 %Galveston County74.4Maverick County: 73.2 %Maverick County73.2Cameron County: 71 %Cameron County71Denton County: 65.2 %Denton County65.2Kaufman County: 65.2 %Kaufman County65.2Navarro County: 63.8 %Navarro County63.8Kleberg County: 62.5 %Kleberg County62.5Montgomery County: 62.5 %Montgomery County62.5Orange County: 62.3 %Orange County62.3Nueces County: 60.8 %Nueces County60.8Harrison County: 60.1 %Harrison County60.1Hidalgo County: 59.7 %Hidalgo County59.7Jefferson County: 58.4 %Jefferson County58.4Webb County: 53.1 %Webb County53.1Bowie County: 52.2 %Bowie County52.2Bexar County: 51.2 %Bexar County51.2Travis County: 50.7 %Travis County50.7Ellis County: 50.1 %Ellis County50.1Tarrant County: 48.5 %Tarrant County48.5Dallas County: 44.1 %Dallas County44.1El Paso County: 32.9 %El Paso County32.9Harris County: 29.3 %Harris County29.3
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Polk County97.4-1.2 pts
2Culberson County94-4.2 pts
2Hunt County94-1.9 pts
4Victoria County93.3-1 pts
5Gregg County93.1+1.3 pts
6Smith County92.3-1.7 pts
7Potter County92.2-3.4 pts
7Rockwall County92.2+0.3 pts
9Hood County90.8-2.1 pts
9Parker County90.8-0.4 pts
11Collin County86.2-1.4 pts
12McLennan County86-3.3 pts
13Fayette County85.8+7.4 pts
14Brazoria County85.7+0.2 pts
15Lubbock County84.7-11.9 pts
16Bell County83-7.7 pts
17Ector County82.9+3.4 pts
18Johnson County80.9-3.1 pts
19Brewster County79-3.7 pts
20Randall County78.1-9.5 pts
21Galveston County74.4+4.3 pts
22Maverick County73.2+2.1 pts
23Cameron County71+10.9 pts
24Denton County65.2-2.6 pts
24Kaufman County65.2-10.8 pts
26Navarro County63.8-7.2 pts
27Kleberg County62.5-8.7 pts
27Montgomery County62.5+8.7 pts
29Orange County62.3-15 pts
30Nueces County60.8-13.5 pts
31Harrison County60.1-12.3 pts
32Hidalgo County59.7-3.7 pts
33Jefferson County58.4-6.4 pts
34Webb County53.1-7.6 pts
35Bowie County52.2-2 pts
36Bexar County51.2-3.2 pts
37Travis County50.7-9.1 pts
38Ellis County50.1-13.8 pts
39Tarrant County48.5-5.3 pts
40Dallas County44.1-7.3 pts
41El Paso County32.9-0.7 pts
42Harris County29.3-2.9 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. 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: 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), 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: 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), 2017. 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=2017. 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), 2017. 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=2017.

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), 2017 [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=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: 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), 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/good-air-quality-days-share/texas-counties?period=2017. 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), 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/good-air-quality-days-share/texas-counties?period=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/texas-counties?period=2017.
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 97.4% in 2017, according to EPA.

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

Harris County, with 29.3% 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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 21 counties have no value for 2017 and are not ranked.

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

Counties in Texas: more rankings