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

Tulsa County had the highest highest daily Air Quality Index (US EPA) of 25 counties in 2000, at 219. Payne County had the lowest, at 74. The median was 101. Source: the U.S. Environmental Protection Agency.

Highest219Tulsa County

Lowest74Payne County

Median10125 counties

Map of counties, 2000

Under 79
79 to 96
96 to 130
130 to 170
170 and over
No data

index, 2000. 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, 2000

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

Full ranking

Rank	Counties	2000 index	Change on 1999
1	Tulsa County	219	+24
2	Love County	205	+20
3	Marshall County	192	-8
4	Cherokee County	185	-5
5	Comanche County	169	+22
6	Jefferson County	166	+10
7	Kay County	161	-26
7	McClain County	161	-21
9	Cleveland County	154	-2
9	Oklahoma County	154	-5
11	Garfield County	115	+44
12	Ottawa County	110	+22
13	Latimer County	101	-18
14	Custer County	99	+28
15	Muskogee County	97	+21
16	Mayes County	94	+18
17	Pittsburg County	93	-1
18	Canadian County	87	+14
19	Carter County	83	+5
20	Pottawatomie County	80	0
21	Pawnee County	77	n/a
21	Seminole County	77	n/a
23	Lincoln County	75	n/a
24	Caddo County	74	n/a
24	Payne County	74	-4

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 2000 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 Oklahoma by highest daily Air Quality Index (US EPA), 2000) [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 Oklahoma by highest daily Air Quality Index (US EPA), 2000. 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/oklahoma-counties?period=2000. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Oklahoma by highest daily Air Quality Index (US EPA), 2000. 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/oklahoma-counties?period=2000.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Oklahoma by highest daily Air Quality Index (US EPA), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/oklahoma-counties?period=2000 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_oklahoma_by_2000,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Oklahoma by highest daily Air Quality Index (US EPA), 2000}},
  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/oklahoma-counties?period=2000. 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 Oklahoma by highest daily Air Quality Index (US EPA), 2000
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/oklahoma-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/oklahoma-counties?period=2000.
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 Oklahoma by highest daily Air Quality Index (US EPA) using official data, and cite the source.

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

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

Tulsa County, with 219 in 2000, according to the U.S. Environmental Protection Agency.

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

Payne County, with 74 in 2000.

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 2000 and are not ranked.