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 2014, at 92.5%. Lane County had the lowest, at 52.1%. The median was 75.8%. Source: EPA.

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Highest92.5Columbia County
Lowest52.1Lane County
Median75.823 counties

Map of counties, 2014

Baker County: 77.8 %Benton County: 87.4 %Clackamas County: 86.3 %Columbia County: 92.5 %Crook County: 68.5 %Deschutes County: 81.9 %Douglas County: 82.7 %Grant County: 60.2 %Harney County: 63.3 %Jackson County: 59.7 %Jefferson County: 63.4 %Josephine County: 72.3 %Klamath County: 60.8 %Lake County: 75.8 %Lane County: 52.1 %Linn County: 75.6 %Marion County: 78.6 %Multnomah County: 79.5 %Umatilla County: 75.6 %Union County: 70.2 %Wallowa County: 82.7 %Wasco County: 83.8 %Washington County: 77 %
  • Under 63
  • 63 to 75
  • 75 to 78
  • 78 to 83
  • 83 and over
  • No data
%, 2014. 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, 2014

Columbia County: 92.5 %Columbia County92.5Benton County: 87.4 %Benton County87.4Clackamas County: 86.3 %Clackamas County86.3Wasco County: 83.8 %Wasco County83.8Douglas County: 82.7 %Douglas County82.7Wallowa County: 82.7 %Wallowa County82.7Deschutes County: 81.9 %Deschutes County81.9Multnomah County: 79.5 %Multnomah County79.5Marion County: 78.6 %Marion County78.6Baker County: 77.8 %Baker County77.8Washington County: 77 %Washington County77Lake County: 75.8 %Lake County75.8Linn County: 75.6 %Linn County75.6Umatilla County: 75.6 %Umatilla County75.6Josephine County: 72.3 %Josephine County72.3Union County: 70.2 %Union County70.2Crook County: 68.5 %Crook County68.5Jefferson County: 63.4 %Jefferson County63.4Harney County: 63.3 %Harney County63.3Klamath County: 60.8 %Klamath County60.8Grant County: 60.2 %Grant County60.2Jackson County: 59.7 %Jackson County59.7Lane County: 52.1 %Lane County52.1Columbia County: 92.5 %Columbia County92.5Benton County: 87.4 %Benton County87.4Clackamas County: 86.3 %Clackamas County86.3Wasco County: 83.8 %Wasco County83.8Douglas County: 82.7 %Douglas County82.7Wallowa County: 82.7 %Wallowa County82.7Deschutes County: 81.9 %Deschutes County81.9Multnomah County: 79.5 %Multnomah County79.5Marion County: 78.6 %Marion County78.6Baker County: 77.8 %Baker County77.8Washington County: 77 %Washington County77Lake County: 75.8 %Lake County75.8Linn County: 75.6 %Linn County75.6Umatilla County: 75.6 %Umatilla County75.6Josephine County: 72.3 %Josephine County72.3Union County: 70.2 %Union County70.2Crook County: 68.5 %Crook County68.5Jefferson County: 63.4 %Jefferson County63.4Harney County: 63.3 %Harney County63.3Klamath County: 60.8 %Klamath County60.8Grant County: 60.2 %Grant County60.2Jackson County: 59.7 %Jackson County59.7Lane County: 52.1 %Lane County52.1
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2014 (%)Change on 2013
1Columbia County92.5+10.5 pts
2Benton County87.4+8 pts
3Clackamas County86.3-6.3 pts
4Wasco County83.8+7.6 pts
5Douglas County82.7+11.5 pts
5Wallowa County82.7+11.3 pts
7Deschutes County81.9+6.3 pts
8Multnomah County79.5+12.4 pts
9Marion County78.6+10.2 pts
10Baker County77.8+16.7 pts
11Washington County77+9.3 pts
12Lake County75.8+17.7 pts
13Linn County75.6+6.3 pts
13Umatilla County75.6+15.2 pts
15Josephine County72.3+20.2 pts
16Union County70.2+9.7 pts
17Crook County68.5+14.3 pts
18Jefferson County63.4-16.6 pts
19Harney County63.3+4.1 pts
20Klamath County60.8+11.9 pts
21Grant County60.2+16.6 pts
22Jackson County59.7+19.2 pts
23Lane County52.1-3.2 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 2014 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), 2014) [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), 2014. 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=2014. 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), 2014. 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=2014.

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), 2014 [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=2014 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2014,
  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), 2014}},
  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=2014. 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), 2014
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=2014
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2014.
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 92.5% in 2014, according to EPA.

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

Lane County, with 52.1% in 2014.

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 2014 and are not ranked.

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

Counties in Oregon: more rankings