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)

Coos County had the highest share of days with good air quality (US EPA AQI) of 24 counties in 2012, at 97.8%. Jackson County had the lowest, at 53.6%. The median was 75.4%. Source: EPA.

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Highest97.8Coos County
Lowest53.6Jackson County
Median75.424 counties

Map of counties, 2012

Baker County: 75.1 %Benton County: 86.2 %Clackamas County: 86.2 %Columbia County: 91.4 %Coos County: 97.8 %Crook County: 66.4 %Deschutes County: 76.8 %Douglas County: 84.5 %Grant County: 62.3 %Harney County: 61.4 %Jackson County: 53.6 %Jefferson County: 80 %Josephine County: 75.7 %Klamath County: 60 %Lake County: 68.9 %Lane County: 57.7 %Linn County: 77.9 %Marion County: 78.3 %Multnomah County: 71.9 %Umatilla County: 66.8 %Union County: 71.2 %Wallowa County: 83.2 %Wasco County: 80.5 %Washington County: 73.5 %
  • Under 65
  • 65 to 72
  • 72 to 78
  • 78 to 84
  • 84 and over
  • No data
%, 2012. 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, 2012

Coos County: 97.8 %Coos County97.8Columbia County: 91.4 %Columbia County91.4Benton County: 86.2 %Benton County86.2Clackamas County: 86.2 %Clackamas County86.2Douglas County: 84.5 %Douglas County84.5Wallowa County: 83.2 %Wallowa County83.2Wasco County: 80.5 %Wasco County80.5Jefferson County: 80 %Jefferson County80Marion County: 78.3 %Marion County78.3Linn County: 77.9 %Linn County77.9Deschutes County: 76.8 %Deschutes County76.8Josephine County: 75.7 %Josephine County75.7Baker County: 75.1 %Baker County75.1Washington County: 73.5 %Washington County73.5Multnomah County: 71.9 %Multnomah County71.9Union County: 71.2 %Union County71.2Lake County: 68.9 %Lake County68.9Umatilla County: 66.8 %Umatilla County66.8Crook County: 66.4 %Crook County66.4Grant County: 62.3 %Grant County62.3Harney County: 61.4 %Harney County61.4Klamath County: 60 %Klamath County60Lane County: 57.7 %Lane County57.7Jackson County: 53.6 %Jackson County53.6Coos County: 97.8 %Coos County97.8Columbia County: 91.4 %Columbia County91.4Benton County: 86.2 %Benton County86.2Clackamas County: 86.2 %Clackamas County86.2Douglas County: 84.5 %Douglas County84.5Wallowa County: 83.2 %Wallowa County83.2Wasco County: 80.5 %Wasco County80.5Jefferson County: 80 %Jefferson County80Marion County: 78.3 %Marion County78.3Linn County: 77.9 %Linn County77.9Deschutes County: 76.8 %Deschutes County76.8Josephine County: 75.7 %Josephine County75.7Baker County: 75.1 %Baker County75.1Washington County: 73.5 %Washington County73.5Multnomah County: 71.9 %Multnomah County71.9Union County: 71.2 %Union County71.2Lake County: 68.9 %Lake County68.9Umatilla County: 66.8 %Umatilla County66.8Crook County: 66.4 %Crook County66.4Grant County: 62.3 %Grant County62.3Harney County: 61.4 %Harney County61.4Klamath County: 60 %Klamath County60Lane County: 57.7 %Lane County57.7Jackson County: 53.6 %Jackson County53.6
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2012 (%)Change on 2011
1Coos County97.8+6.7 pts
2Columbia County91.4+7.2 pts
3Benton County86.2+5.9 pts
3Clackamas County86.2-7.9 pts
5Douglas County84.5+5.1 pts
6Wallowa County83.2-1.3 pts
7Wasco County80.5-5.3 pts
8Jefferson County80+0.6 pts
9Marion County78.3+2.4 pts
10Linn County77.9+15.1 pts
11Deschutes County76.8-3.7 pts
12Josephine County75.7+4.2 pts
13Baker County75.1+2.9 pts
14Washington County73.5+1.7 pts
15Multnomah County71.9+0.7 pts
16Union County71.2-2.4 pts
17Lake County68.9-3.6 pts
18Umatilla County66.8-8.9 pts
19Crook County66.4-1.3 pts
20Grant County62.3+2.9 pts
21Harney County61.4+1.3 pts
22Klamath County60-1.4 pts
23Lane County57.7+0.7 pts
24Jackson County53.6-10 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. 2 counties with data in other periods have no value for 2012 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), 2012) [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), 2012. 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=2012. 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), 2012. 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=2012.

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), 2012 [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=2012 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2012,
  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), 2012}},
  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=2012. 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), 2012
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=2012
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2012.
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)?

Coos County, with 97.8% in 2012, according to EPA.

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

Jackson County, with 53.6% in 2012.

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. 2 counties have no value for 2012 and are not ranked.

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

Counties in Oregon: more rankings