Highest daily Air Quality Index (US EPA) in Wasco County

Highest daily Air Quality Index (US EPA) in Wasco County was 81 in 2025, according to the U.S. Environmental Protection Agency. That is down 12 from 2024.

2025, index81
Change on 2024-12
Series high5992020
Series low491999

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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Highest daily Air Quality Index (US EPA) in Wasco County, 1986 to 2025

02004006001986200220072012201720251986: 78 index1987: 83 index1999: 49 index2000: 103 index2001: 117 index2002: 90 index2003: 75 index2004: 124 index2005: 99 index2006: 155 index2007: 95 index2008: 94 index2009: 83 index2010: 104 index2011: 87 index2012: 76 index2013: 183 index2014: 101 index2015: 158 index2016: 80 index2017: 278 index2018: 156 index2019: 89 index2020: 599 index2021: 163 index2022: 50 index2023: 214 index2024: 93 index2025: 81 index020040060019862007201720251986: 78 index1987: 83 index1999: 49 index2000: 103 index2001: 117 index2002: 90 index2003: 75 index2004: 124 index2005: 99 index2006: 155 index2007: 95 index2008: 94 index2009: 83 index2010: 104 index2011: 87 index2012: 76 index2013: 183 index2014: 101 index2015: 158 index2016: 80 index2017: 278 index2018: 156 index2019: 89 index2020: 599 index2021: 163 index2022: 50 index2023: 214 index2024: 93 index2025: 81 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 29 values
Periodindex
202581
202493
2023214
202250
2021163
2020599
201989
2018156
2017278
201680
2015158
2014101
2013183
201276
201187
2010104
200983
200894
200795
2006155
200599
2004124
200375
200290
2001117
2000103
199949
198783
198678

Wasco County compared with nearby places

Baker County: 85 indexClackamas County: 119 indexColumbia County: 69 indexCrook County: 144 indexDeschutes County: 153 indexGrant County: 89 indexHarney County: 93 indexJackson County: 152 indexJefferson County: 90 indexJosephine County: 208 indexKlamath County: 149 indexLake County: 105 indexLane County: 153 indexLinn County: 122 indexMarion County: 85 indexMultnomah County: 87 indexUmatilla County: 95 indexUnion County: 79 indexWallowa County: 88 indexWasco County: 81 indexWashington County: 88 index
  • Under 85
  • 85 to 89
  • 89 to 110
  • 110 to 150
  • 150 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Wasco 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

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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: highest 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: highest daily AQI (Highest daily Air Quality Index (US EPA), Wasco County, 1986 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: highest daily AQI, Highest daily Air Quality Index (US EPA), Wasco County, 1986 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/highest-daily-air-quality-index/wasco-county-oregon. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Highest daily Air Quality Index (US EPA), Wasco County, 1986 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/highest-daily-air-quality-index/wasco-county-oregon.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Wasco County, 1986 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/wasco-county-oregon (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Wasco County, 1986 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/highest-daily-air-quality-index/wasco-county-oregon. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Highest daily Air Quality Index (US EPA), Wasco County, 1986 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/highest-daily-air-quality-index/wasco-county-oregon
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/wasco-county-oregon.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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 highest daily Air Quality Index (US EPA) in Wasco County?

Highest daily Air Quality Index (US EPA) in Wasco County was 81 in 2025, according to the U.S. Environmental Protection Agency. That is down 12 from 2024.

Where does this figure come from?

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

What was the highest highest daily Air Quality Index (US EPA) in Wasco County?

599 in 2020, the highest value since 1986 in this series.

Related statistics for Wasco County

All statistics for Wasco County | Wasco County in figures