Counties in Texas by highest daily Air Quality Index (US EPA)

Brazoria County had the highest highest daily Air Quality Index (US EPA) of 43 counties in 2014, at 174. Wichita County had the lowest, at 59. The median was 105. Source: the U.S. Environmental Protection Agency.

Highest174Brazoria County

Lowest59Wichita County

Median10543 counties

Map of counties, 2014

Under 84
84 to 97
97 to 110
110 to 120
120 to 140
140 and over
No data

index, 2014. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2014

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2014 index	Change on 2013
1	Brazoria County	174	+2
2	Hood County	164	-5
3	El Paso County	160	-8
4	Denton County	156	-5
4	Tarrant County	156	-31
6	Harris County	151	-46
7	Collin County	143	+3
8	Bexar County	136	-18
9	Jefferson County	133	+11
9	Montgomery County	133	-17
11	Johnson County	129	-14
11	Orange County	129	0
13	Parker County	126	-14
14	Potter County	120	+44
15	Galveston County	119	+7
16	Gregg County	115	-14
17	Bell County	112	-3
17	Polk County	112	+11
19	Dallas County	106	-48
20	McLennan County	105	-10
20	Nueces County	105	+5
20	Rockwall County	105	-14
23	Harrison County	101	-7
24	Lubbock County	100	-70
24	Smith County	100	-26
26	Cameron County	99	+3
26	Kleberg County	99	-8
28	Ellis County	97	-53
28	Travis County	97	-32
30	Navarro County	93	-33
30	Randall County	93	-29
30	Victoria County	93	+13
33	Fayette County	90	+2
34	Hidalgo County	89	-17
35	Ector County	88	-24
36	Brewster County	84	-6
36	Kaufman County	84	-49
36	Webb County	84	-38
39	Maverick County	81	-24
40	Hunt County	80	-35
41	Bowie County	75	-20
42	Culberson County	72	-48
43	Wichita County	59	-30

Other periods

About this ranking

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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. 20 counties with data in other periods have no value for 2014 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: highest 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: highest daily AQI (Counties in Texas by highest daily Air Quality Index (US EPA), 2014) [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: highest daily AQI, Counties in Texas by highest daily Air Quality Index (US EPA), 2014. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/texas-counties?period=2014. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Texas by highest daily Air Quality Index (US EPA), 2014. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/texas-counties?period=2014.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Texas by highest daily Air Quality Index (US EPA), 2014 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/texas-counties?period=2014 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_texas_by_2014,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Texas by highest daily Air Quality Index (US EPA), 2014}},
  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/highest-daily-air-quality-index/texas-counties?period=2014. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Counties in Texas by highest daily Air Quality Index (US EPA), 2014
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/highest-daily-air-quality-index/texas-counties?period=2014
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/texas-counties?period=2014.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -

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Questions

Which county has the highest highest daily Air Quality Index (US EPA)?

Brazoria County, with 174 in 2014, according to the U.S. Environmental Protection Agency.

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

Wichita County, with 59 in 2014.

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: highest daily AQI. Retrieved 2026-10-12. 20 counties have no value for 2014 and are not ranked.