Data / Highest daily Air Quality Index (US EPA) / Washington County

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

Highest daily Air Quality Index (US EPA) in Washington County was 83 in 2010, according to the U.S. Environmental Protection Agency. That is up 2 from 2009.

2010, index83
Change on 2009+2
Series high2011988
Series low812008

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 Washington County, 1988 to 2010

751001251501752002251988200220042006200820101988: 201 index2001: 122 index2002: 96 index2003: 104 index2004: 97 index2005: 119 index2006: 102 index2007: 95 index2008: 81 index2009: 81 index2010: 83 index501001502002501988200420101988: 201 index2001: 122 index2002: 96 index2003: 104 index2004: 97 index2005: 119 index2006: 102 index2007: 95 index2008: 81 index2009: 81 index2010: 83 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 11 values
Periodindex
201083
200981
200881
200795
2006102
2005119
200497
2003104
200296
2001122
1988201

Washington County compared with nearby places

Allen County: 121 indexBoone County: 122 indexCarroll County: 119 indexClark County: 147 indexDelaware County: 108 indexDubois County: 92 indexElkhart County: 110 indexFloyd County: 183 indexGibson County: 86 indexGreene County: 119 indexHamilton County: 122 indexHancock County: 105 indexHendricks County: 100 indexHenry County: 107 indexHoward County: 113 indexHuntington County: 90 indexJackson County: 105 indexJohnson County: 105 indexKnox County: 112 indexLake County: 133 indexLaPorte County: 151 indexMadison County: 100 indexMarion County: 143 indexMonroe County: 89 indexMorgan County: 87 indexPerry County: 122 indexPorter County: 133 indexPosey County: 105 indexSt. Joseph County: 128 indexShelby County: 93 indexSpencer County: 88 indexTippecanoe County: 120 indexVanderburgh County: 122 indexVigo County: 115 indexWabash County: 105 indexWarrick County: 122 indexWashington County: 83 indexWhitley County: 102 index
  • Under 92
  • 92 to 110
  • 110 to 120
  • 120 to 130
  • 130 and over
  • No data
Highest daily Air Quality Index (US EPA), 2010, 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

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, 1988 to 2010) [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, 1988 to 2010. 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-indiana. 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, 1988 to 2010. 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-indiana.

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, 1988 to 2010 [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-indiana (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2010,
  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, 1988 to 2010}},
  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-indiana. 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, 1988 to 2010
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-indiana
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/washington-county-indiana.
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 83 in 2010, according to the U.S. Environmental Protection Agency. That is up 2 from 2009.

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?

201 in 1988, the highest value since 1988 in this series.

Related statistics for Washington County

All statistics for Washington County | Washington County in figures