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

Tarrant County had the highest highest daily Air Quality Index (US EPA) of 42 counties in 2016, at 174. Culberson County had the lowest, at 53. The median was 100. Source: the U.S. Environmental Protection Agency.

Highest174Tarrant County

Lowest53Culberson County

Median10042 counties

Map of counties, 2016

Under 79
79 to 87
87 to 100
100 to 110
110 to 140
140 and over
No data

index, 2016. 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, 2016

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

Full ranking

Rank	Counties	2016 index	Change on 2015
1	Tarrant County	174	+2
2	Bexar County	164	+8
3	Harris County	159	-44
4	Parker County	156	+23
5	Johnson County	150	-6
6	El Paso County	147	+11
6	Galveston County	147	-43
8	Denton County	143	-29
9	Dallas County	140	-7
10	Hood County	133	-18
10	Montgomery County	133	0
12	Jefferson County	122	-42
13	Collin County	119	-24
14	Brazoria County	115	-49
15	Hidalgo County	114	+7
16	Randall County	112	+15
17	Cameron County	110	+2
18	Travis County	105	-45
19	Ector County	102	+26
20	Smith County	101	-7
21	Bell County	100	-33
21	Ellis County	100	-36
21	Gregg County	100	-43
24	Webb County	97	+2
25	Nueces County	94	-18
26	Kleberg County	93	-2
27	Victoria County	90	-15
28	Orange County	87	-13
29	Fayette County	86	+6
30	Navarro County	85	-20
31	Brewster County	84	-3
31	Maverick County	84	+1
33	Kaufman County	82	-11
34	Bowie County	79	-2
34	Harrison County	79	-17
36	Polk County	77	-16
36	Rockwall County	77	-63
38	McLennan County	76	-39
39	Hunt County	67	-13
40	Lubbock County	59	n/a
41	Potter County	58	-70
42	Culberson County	53	-13

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. 21 counties with data in other periods have no value for 2016 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), 2016) [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), 2016. 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=2016. 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), 2016. 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=2016.

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), 2016 [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=2016 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_texas_by_2016,
  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), 2016}},
  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=2016. 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), 2016
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=2016
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/texas-counties?period=2016.
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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Rank Counties in Texas by highest daily Air Quality Index (US EPA) using official data, and cite the source.

rank_places {"indicator":"aqi_max","level":"province","within":"Texas","limit":10}
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Questions

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

Tarrant County, with 174 in 2016, according to the U.S. Environmental Protection Agency.

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

Culberson County, with 53 in 2016.

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. 21 counties have no value for 2016 and are not ranked.