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

Highest daily Air Quality Index (US EPA) in Washington County was 74 in 2025, according to the U.S. Environmental Protection Agency. That is down 27 from 2024.

2025, index74

Change on 2024-27

Series high1512012

Series low441991

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

Highest daily Air Quality Index (US EPA) in Washington County, 1989 to 2025

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.

All 35 values

Period	index
2025	74
2024	101
2023	119
2022	119
2021	119
2020	150
2019	97
2018	87
2017	83
2016	77
2015	90
2014	88
2013	97
2012	151
2011	140
2010	112
2009	122
2008	87
2007	115
2006	54
2004	77
2003	87
2002	90
2001	85
2000	98
1999	91
1997	50
1996	52
1995	48
1994	49
1993	53
1992	55
1991	44
1990	53
1989	56

Washington County compared with nearby places

Under 77
77 to 84
84 to 91
91 to 110
110 and over
No data

Highest daily Air Quality Index (US EPA), 2025, index. Washington 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

Counties in Arkansas by highest daily Air Quality Index (US EPA) 26 places

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), Washington County, 1989 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), Washington County, 1989 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/washington-county-arkansas. 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), Washington County, 1989 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/washington-county-arkansas.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Washington County, 1989 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/washington-county-arkansas (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), Washington County, 1989 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/washington-county-arkansas. 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), Washington County, 1989 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/washington-county-arkansas
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/washington-county-arkansas.
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 Washington County?

Highest daily Air Quality Index (US EPA) in Washington County was 74 in 2025, according to the U.S. Environmental Protection Agency. That is down 27 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 Washington County?

151 in 2012, the highest value since 1989 in this series.

Related statistics for Washington County

All statistics for Washington County | Washington County in figures