Counties in Oklahoma by share of days with good air quality (US EPA AQI)

Latimer County had the highest share of days with good air quality (US EPA AQI) of 25 counties in 2000, at 94.4%. Tulsa County had the lowest, at 26%. The median was 57.5%. Source: EPA.

Highest94.4Latimer County

Lowest26Tulsa County

Median57.525 counties

Map of counties, 2000

Under 42
42 to 51
51 to 61
61 to 69
69 and over
No data

%, 2000. 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, 2000

%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2000 (%)	Change on 1999
1	Latimer County	94.4	+0.6 pts
2	Garfield County	83.6	-11 pts
3	Muskogee County	81.9	-12.9 pts
4	Mayes County	81.2	-13.4 pts
5	Cleveland County	74.7	-3.1 pts
6	McClain County	67.4	-14.8 pts
7	Cherokee County	65.8	+7.9 pts
8	Comanche County	62.6	-11.9 pts
9	Marshall County	62	+9.4 pts
10	Custer County	61.3	+3.4 pts
11	Jefferson County	60.2	+5 pts
12	Kay County	59.8	-14.9 pts
13	Caddo County	57.5	n/a
14	Love County	56.7	-4.9 pts
15	Pittsburg County	51.3	+15.1 pts
16	Canadian County	50	-14.3 pts
17	Carter County	49.5	+6.6 pts
18	Lincoln County	48	n/a
19	Pawnee County	45	n/a
20	Pottawatomie County	43.1	+5.3 pts
21	Payne County	37	-11.7 pts
22	Oklahoma County	36.9	-13.2 pts
23	Seminole County	36.7	n/a
24	Ottawa County	36.4	-2.5 pts
25	Tulsa County	26	-22.2 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. 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: 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 Oklahoma by share of days with good air quality (US EPA AQI), 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: good days as a share of days with an AQI, calculated with stored counts, Counties in Oklahoma by share of days with good air quality (US EPA AQI), 2000. 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/oklahoma-counties?period=2000. 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 Oklahoma by share of days with good air quality (US EPA AQI), 2000. 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/oklahoma-counties?period=2000.

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 Oklahoma by share of days with good air quality (US EPA AQI), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/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: good days as a share of days with an AQI, calculated with stored counts: Counties in Oklahoma by share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/oklahoma-counties?period=2000. 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 Oklahoma by share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/oklahoma-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oklahoma-counties?period=2000.
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 Oklahoma 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)?

Latimer County, with 94.4% in 2000, according to EPA.

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

Tulsa County, with 26% 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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 20 counties have no value for 2000 and are not ranked.