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

Counties in Oregon by median Air Quality Index (US EPA), 2022

Douglas County had the highest median Air Quality Index (US EPA) of 23 counties in 2022, at 53. Wasco County had the lowest, at 16. The median was 33. Source: the U.S. Environmental Protection Agency.

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Highest53Douglas County
Lowest16Wasco County
Median3323 counties

Map of counties, 2022

Baker County: 32 indexBenton County: 21 indexClackamas County: 33 indexColumbia County: 31 indexCrook County: 24 indexDeschutes County: 23 indexDouglas County: 53 indexGrant County: 46 indexHarney County: 41 indexJackson County: 44 indexJefferson County: 26 indexJosephine County: 39 indexKlamath County: 38 indexLake County: 25 indexLane County: 44 indexLinn County: 33 indexMarion County: 36 indexMultnomah County: 36 indexUmatilla County: 39 indexUnion County: 28 indexWallowa County: 27 indexWasco County: 16 indexWashington County: 37 index
  • Under 25
  • 25 to 32
  • 32 to 36
  • 36 to 40
  • 40 and over
  • No data
index, 2022. 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, 2022

Douglas County: 53 indexDouglas County53Grant County: 46 indexGrant County46Jackson County: 44 indexJackson County44Lane County: 44 indexLane County44Harney County: 41 indexHarney County41Josephine County: 39 indexJosephine County39Umatilla County: 39 indexUmatilla County39Klamath County: 38 indexKlamath County38Washington County: 37 indexWashington County37Marion County: 36 indexMarion County36Multnomah County: 36 indexMultnomah County36Clackamas County: 33 indexClackamas County33Linn County: 33 indexLinn County33Baker County: 32 indexBaker County32Columbia County: 31 indexColumbia County31Union County: 28 indexUnion County28Wallowa County: 27 indexWallowa County27Jefferson County: 26 indexJefferson County26Lake County: 25 indexLake County25Crook County: 24 indexCrook County24Deschutes County: 23 indexDeschutes County23Benton County: 21 indexBenton County21Wasco County: 16 indexWasco County16Douglas County: 53 indexDouglas County53Grant County: 46 indexGrant County46Jackson County: 44 indexJackson County44Lane County: 44 indexLane County44Harney County: 41 indexHarney County41Josephine County: 39 indexJosephine County39Umatilla County: 39 indexUmatilla County39Klamath County: 38 indexKlamath County38Washington County: 37 indexWashington County37Marion County: 36 indexMarion County36Multnomah County: 36 indexMultnomah County36Clackamas County: 33 indexClackamas County33Linn County: 33 indexLinn County33Baker County: 32 indexBaker County32Columbia County: 31 indexColumbia County31Union County: 28 indexUnion County28Wallowa County: 27 indexWallowa County27Jefferson County: 26 indexJefferson County26Lake County: 25 indexLake County25Crook County: 24 indexCrook County24Deschutes County: 23 indexDeschutes County23Benton County: 21 indexBenton County21Wasco County: 16 indexWasco County16
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2022
index		Change on 2021
1Douglas County53+24
2Grant County46-5
3Jackson County44-4
3Lane County440
5Harney County41-7
6Josephine County39+3
6Umatilla County39+1
8Klamath County38-16
9Washington County37+1
10Marion County360
10Multnomah County360
12Clackamas County33+2
12Linn County33-1
14Baker County32+3
15Columbia County31+2
16Union County28+1
17Wallowa County27+1
18Jefferson County26-2
19Lake County25-3
20Crook County24-4
21Deschutes County23-2
22Benton County21-1
23Wasco County16-6

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. 3 counties with data in other periods have no value for 2022 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 Oregon by median Air Quality Index (US EPA), 2022) [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 Oregon by median Air Quality Index (US EPA), 2022. 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/oregon-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Oregon by median Air Quality Index (US EPA), 2022. 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/oregon-counties.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Oregon by median Air Quality Index (US EPA), 2022 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/oregon-counties (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2022,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Oregon by median Air Quality Index (US EPA), 2022}},
  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/oregon-counties. 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 Oregon by median Air Quality Index (US EPA), 2022
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/oregon-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/oregon-counties.
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 Oregon by median Air Quality Index (US EPA) using official data, and cite the source.
rank_places {"indicator":"aqi_median","level":"province","within":"Oregon","limit":10}
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Questions

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

Douglas County, with 53 in 2022, according to the U.S. Environmental Protection Agency.

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

Wasco County, with 16 in 2022.

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. 3 counties have no value for 2022 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Oregon: more rankings