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 2002, at 57. Muskogee County had the lowest, at 31. The median was 40. Source: the U.S. Environmental Protection Agency.

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Highest57Tulsa County
Lowest31Muskogee County
Median4025 counties

Map of counties, 2002

Adair County: 40 indexCaddo County: 38 indexCanadian County: 39 indexCarter County: 44 indexCherokee County: 38 indexCleveland County: 37 indexComanche County: 40 indexCuster County: 37 indexDewey County: 33 indexEllis County: 34 indexGarfield County: 45 indexJefferson County: 43 indexKay County: 43 indexLincoln County: 46 indexMcClain County: 36 indexMarshall County: 44 indexMayes County: 54 indexMuskogee County: 31 indexOklahoma County: 53 indexOttawa County: 39 indexPawnee County: 33 indexPayne County: 46 indexPittsburg County: 43 indexSeminole County: 41 indexTulsa County: 57 index
  • Under 37
  • 37 to 39
  • 39 to 43
  • 43 to 45
  • 45 and over
  • No data
index, 2002. 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, 2002

Tulsa County: 57 indexTulsa County57Mayes County: 54 indexMayes County54Oklahoma County: 53 indexOklahoma County53Lincoln County: 46 indexLincoln County46Payne County: 46 indexPayne County46Garfield County: 45 indexGarfield County45Carter County: 44 indexCarter County44Marshall County: 44 indexMarshall County44Jefferson County: 43 indexJefferson County43Kay County: 43 indexKay County43Pittsburg County: 43 indexPittsburg County43Seminole County: 41 indexSeminole County41Adair County: 40 indexAdair County40Comanche County: 40 indexComanche County40Canadian County: 39 indexCanadian County39Ottawa County: 39 indexOttawa County39Caddo County: 38 indexCaddo County38Cherokee County: 38 indexCherokee County38Cleveland County: 37 indexCleveland County37Custer County: 37 indexCuster County37McClain County: 36 indexMcClain County36Ellis County: 34 indexEllis County34Dewey County: 33 indexDewey County33Pawnee County: 33 indexPawnee County33Muskogee County: 31 indexMuskogee County31Tulsa County: 57 indexTulsa County57Mayes County: 54 indexMayes County54Oklahoma County: 53 indexOklahoma County53Lincoln County: 46 indexLincoln County46Payne County: 46 indexPayne County46Garfield County: 45 indexGarfield County45Carter County: 44 indexCarter County44Marshall County: 44 indexMarshall County44Jefferson County: 43 indexJefferson County43Kay County: 43 indexKay County43Pittsburg County: 43 indexPittsburg County43Seminole County: 41 indexSeminole County41Adair County: 40 indexAdair County40Comanche County: 40 indexComanche County40Canadian County: 39 indexCanadian County39Ottawa County: 39 indexOttawa County39Caddo County: 38 indexCaddo County38Cherokee County: 38 indexCherokee County38Cleveland County: 37 indexCleveland County37Custer County: 37 indexCuster County37McClain County: 36 indexMcClain County36Ellis County: 34 indexEllis County34Dewey County: 33 indexDewey County33Pawnee County: 33 indexPawnee County33Muskogee County: 31 indexMuskogee County31
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2002
index		Change on 2001
1Tulsa County57-6
2Mayes County54+11
3Oklahoma County53-4
4Lincoln County46-1
4Payne County46-2
6Garfield County45+11
7Carter County44-6
7Marshall County44-2
9Jefferson County43-4
9Kay County43-3
9Pittsburg County43-10
12Seminole County41-7
13Adair County40n/a
13Comanche County40-4
15Canadian County39-8
15Ottawa County39-5
17Caddo County38-5
17Cherokee County38-3
19Cleveland County37-2
19Custer County37-4
21McClain County36-4
22Ellis County34n/a
23Dewey County33n/a
23Pawnee County33-9
25Muskogee County31+9

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 2002 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), 2002) [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), 2002. 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=2002. 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), 2002. 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=2002.

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), 2002 [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=2002 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oklahoma_by_2002,
  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), 2002}},
  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=2002. 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), 2002
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=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/oklahoma-counties?period=2002.
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 57 in 2002, according to the U.S. Environmental Protection Agency.

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

Muskogee County, with 31 in 2002.

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 2002 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Oklahoma: more rankings