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 2013, at 97.8%. Jackson County had the lowest, at 40.5%. The median was 67.4%. Source: EPA.

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Highest97.8Coos County
Lowest40.5Jackson County
Median67.424 counties

Map of counties, 2013

Baker County: 61.1 %Benton County: 79.4 %Clackamas County: 92.6 %Columbia County: 82 %Coos County: 97.8 %Crook County: 54.2 %Deschutes County: 75.6 %Douglas County: 71.2 %Grant County: 43.6 %Harney County: 59.2 %Jackson County: 40.5 %Jefferson County: 80 %Josephine County: 52.1 %Klamath County: 48.9 %Lake County: 58.1 %Lane County: 55.3 %Linn County: 69.3 %Marion County: 68.4 %Multnomah County: 67.1 %Umatilla County: 60.4 %Union County: 60.5 %Wallowa County: 71.4 %Wasco County: 76.2 %Washington County: 67.7 %
  • Under 55
  • 55 to 61
  • 61 to 69
  • 69 to 77
  • 77 and over
  • No data
%, 2013. 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, 2013

Coos County: 97.8 %Coos County97.8Clackamas County: 92.6 %Clackamas County92.6Columbia County: 82 %Columbia County82Jefferson County: 80 %Jefferson County80Benton County: 79.4 %Benton County79.4Wasco County: 76.2 %Wasco County76.2Deschutes County: 75.6 %Deschutes County75.6Wallowa County: 71.4 %Wallowa County71.4Douglas County: 71.2 %Douglas County71.2Linn County: 69.3 %Linn County69.3Marion County: 68.4 %Marion County68.4Washington County: 67.7 %Washington County67.7Multnomah County: 67.1 %Multnomah County67.1Baker County: 61.1 %Baker County61.1Union County: 60.5 %Union County60.5Umatilla County: 60.4 %Umatilla County60.4Harney County: 59.2 %Harney County59.2Lake County: 58.1 %Lake County58.1Lane County: 55.3 %Lane County55.3Crook County: 54.2 %Crook County54.2Josephine County: 52.1 %Josephine County52.1Klamath County: 48.9 %Klamath County48.9Grant County: 43.6 %Grant County43.6Jackson County: 40.5 %Jackson County40.5Coos County: 97.8 %Coos County97.8Clackamas County: 92.6 %Clackamas County92.6Columbia County: 82 %Columbia County82Jefferson County: 80 %Jefferson County80Benton County: 79.4 %Benton County79.4Wasco County: 76.2 %Wasco County76.2Deschutes County: 75.6 %Deschutes County75.6Wallowa County: 71.4 %Wallowa County71.4Douglas County: 71.2 %Douglas County71.2Linn County: 69.3 %Linn County69.3Marion County: 68.4 %Marion County68.4Washington County: 67.7 %Washington County67.7Multnomah County: 67.1 %Multnomah County67.1Baker County: 61.1 %Baker County61.1Union County: 60.5 %Union County60.5Umatilla County: 60.4 %Umatilla County60.4Harney County: 59.2 %Harney County59.2Lake County: 58.1 %Lake County58.1Lane County: 55.3 %Lane County55.3Crook County: 54.2 %Crook County54.2Josephine County: 52.1 %Josephine County52.1Klamath County: 48.9 %Klamath County48.9Grant County: 43.6 %Grant County43.6Jackson County: 40.5 %Jackson County40.5
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2013 (%)Change on 2012
1Coos County97.80 pts
2Clackamas County92.6+6.4 pts
3Columbia County82-9.4 pts
4Jefferson County800 pts
5Benton County79.4-6.8 pts
6Wasco County76.2-4.3 pts
7Deschutes County75.6-1.2 pts
8Wallowa County71.4-11.8 pts
9Douglas County71.2-13.3 pts
10Linn County69.3-8.6 pts
11Marion County68.4-9.9 pts
12Washington County67.7-5.8 pts
13Multnomah County67.1-4.8 pts
14Baker County61.1-14 pts
15Union County60.5-10.7 pts
16Umatilla County60.4-6.4 pts
17Harney County59.2-2.2 pts
18Lake County58.1-10.8 pts
19Lane County55.3-2.4 pts
20Crook County54.2-12.2 pts
21Josephine County52.1-23.6 pts
22Klamath County48.9-11.1 pts
23Grant County43.6-18.7 pts
24Jackson County40.5-13.1 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. 2 counties with data in other periods have no value for 2013 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), 2013) [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), 2013. 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=2013. 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), 2013. 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=2013.

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), 2013 [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=2013 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2013,
  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), 2013}},
  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=2013. 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), 2013
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=2013
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2013.
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 2013, according to EPA.

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

Jackson County, with 40.5% in 2013.

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 2013 and are not ranked.

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

Counties in Oregon: more rankings