Median Air Quality Index (US EPA) in Linn County

Median Air Quality Index (US EPA) in Linn County was 27 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024.

2025, index27
Change on 2024+2
Series high551999
Series low252024

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Median Air Quality Index (US EPA) in Linn County, 1985 to 2025

2030405060198519902001200620112016202120251985: 43 index1986: 42 index1987: 36 index1988: 32 index1989: 27 index1990: 29 index1991: 30 index1992: 43 index1999: 55 index2000: 34 index2001: 36 index2002: 39 index2003: 34 index2004: 37 index2005: 29 index2006: 26 index2007: 35 index2008: 45 index2009: 44 index2010: 34 index2011: 34 index2012: 31 index2013: 31 index2014: 33 index2015: 31 index2016: 26 index2017: 32 index2018: 36 index2019: 37 index2020: 36 index2021: 34 index2022: 33 index2023: 34 index2024: 25 index2025: 27 index203040506019852003201520251985: 43 index1986: 42 index1987: 36 index1988: 32 index1989: 27 index1990: 29 index1991: 30 index1992: 43 index1999: 55 index2000: 34 index2001: 36 index2002: 39 index2003: 34 index2004: 37 index2005: 29 index2006: 26 index2007: 35 index2008: 45 index2009: 44 index2010: 34 index2011: 34 index2012: 31 index2013: 31 index2014: 33 index2015: 31 index2016: 26 index2017: 32 index2018: 36 index2019: 37 index2020: 36 index2021: 34 index2022: 33 index2023: 34 index2024: 25 index2025: 27 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 35 values
Periodindex
202527
202425
202334
202233
202134
202036
201937
201836
201732
201626
201531
201433
201331
201231
201134
201034
200944
200845
200735
200626
200529
200437
200334
200239
200136
200034
199955
199243
199130
199029
198927
198832
198736
198642
198543

Linn County compared with nearby places

Baker County: 29 indexClackamas County: 31 indexColumbia County: 27 indexCrook County: 28 indexDeschutes County: 23 indexGrant County: 37 indexHarney County: 28 indexJackson County: 43 indexJefferson County: 28 indexJosephine County: 33 indexKlamath County: 38 indexLake County: 26 indexLane County: 46 indexLinn County: 27 indexMarion County: 35 indexMultnomah County: 37 indexUmatilla County: 41 indexUnion County: 27 indexWallowa County: 26 indexWasco County: 25 indexWashington County: 36 index
  • Under 27
  • 27 to 28
  • 28 to 33
  • 33 to 37
  • 37 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Linn County is outlined. Same source and period for every area shown. Source: U.S. Environmental Protection Agency. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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.

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How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. 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: median daily AQI (Median Air Quality Index (US EPA), Linn County, 1985 to 2025) [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: median daily AQI, Median Air Quality Index (US EPA), Linn County, 1985 to 2025. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/median-air-quality-index/linn-county-oregon. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Median Air Quality Index (US EPA), Linn County, 1985 to 2025. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/median-air-quality-index/linn-county-oregon.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Linn County, 1985 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/median-air-quality-index/linn-county-oregon (Accessed: 12 October 2026).

BibTeX
@misc{environmental_median_air_quality_index_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Median Air Quality Index (US EPA), Linn County, 1985 to 2025}},
  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/en/median-air-quality-index/linn-county-oregon. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. 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: median daily AQI: Median Air Quality Index (US EPA), Linn County, 1985 to 2025
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/en/median-air-quality-index/linn-county-oregon
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/linn-county-oregon.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  - 
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Questions

What is the median Air Quality Index (US EPA) in Linn County?

Median Air Quality Index (US EPA) in Linn County was 27 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: median daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest median Air Quality Index (US EPA) in Linn County?

55 in 1999, the highest value since 1985 in this series.

Related statistics for Linn County

All statistics for Linn County | Linn County in figures