Data / Rankings / Median Air Quality Index (US EPA) / Counties in Oklahoma

Counties in Oklahoma by median Air Quality Index (US EPA)

Tulsa County had the highest median Air Quality Index (US EPA) of 25 counties in 2000, at 59. Garfield County had the lowest, at 20. The median was 47. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest59Tulsa County
Lowest20Garfield County
Median4725 counties

Map of counties, 2000

Caddo County: 50 indexCanadian County: 51 indexCarter County: 51 indexCherokee County: 42 indexCleveland County: 39 indexComanche County: 44 indexCuster County: 45 indexGarfield County: 20 indexJefferson County: 46 indexKay County: 44 indexLatimer County: 27 indexLincoln County: 52 indexLove County: 47 indexMcClain County: 44 indexMarshall County: 46 indexMayes County: 23 indexMuskogee County: 22 indexOklahoma County: 55 indexOttawa County: 56 indexPawnee County: 52 indexPayne County: 54 indexPittsburg County: 50 indexPottawatomie County: 54 indexSeminole County: 54 indexTulsa County: 59 index
  • Under 41
  • 41 to 46
  • 46 to 50
  • 50 to 54
  • 54 and over
  • No data
index, 2000. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2000

Tulsa County: 59 indexTulsa County59Ottawa County: 56 indexOttawa County56Oklahoma County: 55 indexOklahoma County55Payne County: 54 indexPayne County54Pottawatomie County: 54 indexPottawatomie County54Seminole County: 54 indexSeminole County54Lincoln County: 52 indexLincoln County52Pawnee County: 52 indexPawnee County52Canadian County: 51 indexCanadian County51Carter County: 51 indexCarter County51Caddo County: 50 indexCaddo County50Pittsburg County: 50 indexPittsburg County50Love County: 47 indexLove County47Jefferson County: 46 indexJefferson County46Marshall County: 46 indexMarshall County46Custer County: 45 indexCuster County45Comanche County: 44 indexComanche County44Kay County: 44 indexKay County44McClain County: 44 indexMcClain County44Cherokee County: 42 indexCherokee County42Cleveland County: 39 indexCleveland County39Latimer County: 27 indexLatimer County27Mayes County: 23 indexMayes County23Muskogee County: 22 indexMuskogee County22Garfield County: 20 indexGarfield County20Tulsa County: 59 indexTulsa County59Ottawa County: 56 indexOttawa County56Oklahoma County: 55 indexOklahoma County55Payne County: 54 indexPayne County54Pottawatomie County: 54 indexPottawatomie County54Seminole County: 54 indexSeminole County54Lincoln County: 52 indexLincoln County52Pawnee County: 52 indexPawnee County52Canadian County: 51 indexCanadian County51Carter County: 51 indexCarter County51Caddo County: 50 indexCaddo County50Pittsburg County: 50 indexPittsburg County50Love County: 47 indexLove County47Jefferson County: 46 indexJefferson County46Marshall County: 46 indexMarshall County46Custer County: 45 indexCuster County45Comanche County: 44 indexComanche County44Kay County: 44 indexKay County44McClain County: 44 indexMcClain County44Cherokee County: 42 indexCherokee County42Cleveland County: 39 indexCleveland County39Latimer County: 27 indexLatimer County27Mayes County: 23 indexMayes County23Muskogee County: 22 indexMuskogee County22Garfield County: 20 indexGarfield County20
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2000
index		Change on 1999
1Tulsa County59+8
2Ottawa County56+2
3Oklahoma County55+5
4Payne County54+2
4Pottawatomie County54+1
4Seminole County54n/a
7Lincoln County52n/a
7Pawnee County52n/a
9Canadian County51+3
9Carter County51-3
11Caddo County50n/a
11Pittsburg County50-5
13Love County47+2
14Jefferson County46-1
14Marshall County46-4
16Custer County45-2
17Comanche County44+3
17Kay County44+16
17McClain County44+7
20Cherokee County42-3
21Cleveland County39-3
22Latimer County27-3
23Mayes County23+4
24Muskogee County22+3
25Garfield County20+2

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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: median 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: median daily AQI (Counties in Oklahoma by median 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: median daily AQI, Counties in Oklahoma by median 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/median-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: median daily AQI. Counties in Oklahoma by median 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/median-air-quality-index/oklahoma-counties?period=2000.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Oklahoma by median 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/median-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: median daily AQI: Counties in Oklahoma by median 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/median-air-quality-index/oklahoma-counties?period=2000. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median 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: median daily AQI: Counties in Oklahoma by median 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/median-air-quality-index/oklahoma-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-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: median 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 median Air Quality Index (US EPA) using official data, and cite the source.
rank_places {"indicator":"aqi_median","level":"province","within":"Oklahoma","limit":10}
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Questions

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

Tulsa County, with 59 in 2000, according to the U.S. Environmental Protection Agency.

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

Garfield County, with 20 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: median daily AQI. Retrieved 2026-10-12. 20 counties have no value for 2000 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Oklahoma: more rankings