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)

Benton County had the highest share of days with good air quality (US EPA AQI) of 23 counties in 2015, at 86%. Jackson County had the lowest, at 52.3%. The median was 73.2%. Source: EPA.

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Highest86Benton County
Lowest52.3Jackson County
Median73.223 counties

Map of counties, 2015

Baker County: 78.1 %Benton County: 86 %Clackamas County: 85.6 %Columbia County: 85.8 %Crook County: 69.6 %Deschutes County: 80.8 %Douglas County: 80 %Grant County: 59.2 %Harney County: 65.8 %Jackson County: 52.3 %Jefferson County: 65.2 %Josephine County: 66 %Klamath County: 58.4 %Lake County: 74 %Lane County: 58.4 %Linn County: 74.5 %Marion County: 73.2 %Multnomah County: 75.9 %Umatilla County: 67.4 %Union County: 70.2 %Wallowa County: 79.4 %Wasco County: 83.8 %Washington County: 69.6 %
  • Under 65
  • 65 to 70
  • 70 to 75
  • 75 to 80
  • 80 and over
  • No data
%, 2015. 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, 2015

Benton County: 86 %Benton County86Columbia County: 85.8 %Columbia County85.8Clackamas County: 85.6 %Clackamas County85.6Wasco County: 83.8 %Wasco County83.8Deschutes County: 80.8 %Deschutes County80.8Douglas County: 80 %Douglas County80Wallowa County: 79.4 %Wallowa County79.4Baker County: 78.1 %Baker County78.1Multnomah County: 75.9 %Multnomah County75.9Linn County: 74.5 %Linn County74.5Lake County: 74 %Lake County74Marion County: 73.2 %Marion County73.2Union County: 70.2 %Union County70.2Crook County: 69.6 %Crook County69.6Washington County: 69.6 %Washington County69.6Umatilla County: 67.4 %Umatilla County67.4Josephine County: 66 %Josephine County66Harney County: 65.8 %Harney County65.8Jefferson County: 65.2 %Jefferson County65.2Grant County: 59.2 %Grant County59.2Klamath County: 58.4 %Klamath County58.4Lane County: 58.4 %Lane County58.4Jackson County: 52.3 %Jackson County52.3Benton County: 86 %Benton County86Columbia County: 85.8 %Columbia County85.8Clackamas County: 85.6 %Clackamas County85.6Wasco County: 83.8 %Wasco County83.8Deschutes County: 80.8 %Deschutes County80.8Douglas County: 80 %Douglas County80Wallowa County: 79.4 %Wallowa County79.4Baker County: 78.1 %Baker County78.1Multnomah County: 75.9 %Multnomah County75.9Linn County: 74.5 %Linn County74.5Lake County: 74 %Lake County74Marion County: 73.2 %Marion County73.2Union County: 70.2 %Union County70.2Crook County: 69.6 %Crook County69.6Washington County: 69.6 %Washington County69.6Umatilla County: 67.4 %Umatilla County67.4Josephine County: 66 %Josephine County66Harney County: 65.8 %Harney County65.8Jefferson County: 65.2 %Jefferson County65.2Grant County: 59.2 %Grant County59.2Klamath County: 58.4 %Klamath County58.4Lane County: 58.4 %Lane County58.4Jackson County: 52.3 %Jackson County52.3
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2015 (%)Change on 2014
1Benton County86-1.4 pts
2Columbia County85.8-6.7 pts
3Clackamas County85.6-0.7 pts
4Wasco County83.80 pts
5Deschutes County80.8-1.1 pts
6Douglas County80-2.7 pts
7Wallowa County79.4-3.3 pts
8Baker County78.1+0.3 pts
9Multnomah County75.9-3.6 pts
10Linn County74.5-1.1 pts
11Lake County74-1.8 pts
12Marion County73.2-5.4 pts
13Union County70.20 pts
14Crook County69.6+1.1 pts
14Washington County69.6-7.4 pts
16Umatilla County67.4-8.2 pts
17Josephine County66-6.3 pts
18Harney County65.8+2.5 pts
19Jefferson County65.2+1.8 pts
20Grant County59.2-1 pts
21Klamath County58.4-2.4 pts
21Lane County58.4+6.3 pts
23Jackson County52.3-7.4 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 2015 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), 2015) [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), 2015. 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=2015. 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), 2015. 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=2015.

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), 2015 [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=2015 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_oregon_by_2015,
  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), 2015}},
  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=2015. 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), 2015
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=2015
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/oregon-counties?period=2015.
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)?

Benton County, with 86% in 2015, according to EPA.

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

Jackson County, with 52.3% in 2015.

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 2015 and are not ranked.

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

Counties in Oregon: more rankings