Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in Oregon

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

Columbia County had the highest share of days with good air quality (US EPA AQI) of 23 counties in 2017, at 88.4%. Lane County had the lowest, at 54.8%. The median was 70.4%. Source: EPA.

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Highest88.4Columbia County
Lowest54.8Lane County
Median70.423 counties

Map of counties, 2017

Baker County: 74.8 %Benton County: 82.4 %Clackamas County: 82.4 %Columbia County: 88.4 %Crook County: 64.1 %Deschutes County: 76.7 %Douglas County: 74.1 %Grant County: 57.3 %Harney County: 55.6 %Jackson County: 57.8 %Jefferson County: 58.7 %Josephine County: 60 %Klamath County: 59.6 %Lake County: 71.1 %Lane County: 54.8 %Linn County: 69.6 %Marion County: 79.3 %Multnomah County: 76.2 %Umatilla County: 60.8 %Union County: 75.9 %Wallowa County: 76.8 %Wasco County: 68.4 %Washington County: 70.4 %
  • Under 59
  • 59 to 68
  • 68 to 74
  • 74 to 77
  • 77 and over
  • No data
%, 2017. 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, 2017

Columbia County: 88.4 %Columbia County88.4Benton County: 82.4 %Benton County82.4Clackamas County: 82.4 %Clackamas County82.4Marion County: 79.3 %Marion County79.3Wallowa County: 76.8 %Wallowa County76.8Deschutes County: 76.7 %Deschutes County76.7Multnomah County: 76.2 %Multnomah County76.2Union County: 75.9 %Union County75.9Baker County: 74.8 %Baker County74.8Douglas County: 74.1 %Douglas County74.1Lake County: 71.1 %Lake County71.1Washington County: 70.4 %Washington County70.4Linn County: 69.6 %Linn County69.6Wasco County: 68.4 %Wasco County68.4Crook County: 64.1 %Crook County64.1Umatilla County: 60.8 %Umatilla County60.8Josephine County: 60 %Josephine County60Klamath County: 59.6 %Klamath County59.6Jefferson County: 58.7 %Jefferson County58.7Jackson County: 57.8 %Jackson County57.8Grant County: 57.3 %Grant County57.3Harney County: 55.6 %Harney County55.6Lane County: 54.8 %Lane County54.8Columbia County: 88.4 %Columbia County88.4Benton County: 82.4 %Benton County82.4Clackamas County: 82.4 %Clackamas County82.4Marion County: 79.3 %Marion County79.3Wallowa County: 76.8 %Wallowa County76.8Deschutes County: 76.7 %Deschutes County76.7Multnomah County: 76.2 %Multnomah County76.2Union County: 75.9 %Union County75.9Baker County: 74.8 %Baker County74.8Douglas County: 74.1 %Douglas County74.1Lake County: 71.1 %Lake County71.1Washington County: 70.4 %Washington County70.4Linn County: 69.6 %Linn County69.6Wasco County: 68.4 %Wasco County68.4Crook County: 64.1 %Crook County64.1Umatilla County: 60.8 %Umatilla County60.8Josephine County: 60 %Josephine County60Klamath County: 59.6 %Klamath County59.6Jefferson County: 58.7 %Jefferson County58.7Jackson County: 57.8 %Jackson County57.8Grant County: 57.3 %Grant County57.3Harney County: 55.6 %Harney County55.6Lane County: 54.8 %Lane County54.8
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Columbia County88.4-8.7 pts
2Benton County82.4-7.8 pts
2Clackamas County82.4-11.6 pts
4Marion County79.3-4.9 pts
5Wallowa County76.8-9.5 pts
6Deschutes County76.7-15.3 pts
7Multnomah County76.2-12.3 pts
8Union County75.9-5.7 pts
9Baker County74.8-8.9 pts
10Douglas County74.1-16.2 pts
11Lake County71.1-12.2 pts
12Washington County70.4-9.4 pts
13Linn County69.6-11.8 pts
14Wasco County68.4-14.6 pts
15Crook County64.1-10.9 pts
16Umatilla County60.8-20.3 pts
17Josephine County60-18.1 pts
18Klamath County59.6-9.3 pts
19Jefferson County58.7n/a
20Jackson County57.8-14.1 pts
21Grant County57.3-14.8 pts
22Harney County55.6-13.6 pts
23Lane County54.8-15.1 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. 3 counties with data in other periods have no value for 2017 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 Oregon by share of days with good air quality (US EPA AQI), 2017) [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 Oregon by share of days with good air quality (US EPA AQI), 2017. 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/oregon-counties?period=2017. 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 Oregon by share of days with good air quality (US EPA AQI), 2017. 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/oregon-counties?period=2017.

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 Oregon by share of days with good air quality (US EPA AQI), 2017 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2017 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2017,
  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 Oregon by share of days with good air quality (US EPA AQI), 2017}},
  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/oregon-counties?period=2017. 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 Oregon by share of days with good air quality (US EPA AQI), 2017
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/oregon-counties?period=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2017.
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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Questions

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

Columbia County, with 88.4% in 2017, according to EPA.

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

Lane County, with 54.8% in 2017.

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. 3 counties have no value for 2017 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in Oregon: more rankings