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

Highest daily Air Quality Index (US EPA) in Coles County was 41 in 1997, according to the U.S. Environmental Protection Agency. That is down 3 from 1996.

1997, index41
Change on 1996-3
Series high861993
Series low411997

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 Coles County, 1988 to 1997

405060708090198819901992199419971988: 55 index1989: 66 index1990: 62 index1991: 51 index1992: 76 index1993: 86 index1994: 47 index1995: 46 index1996: 44 index1997: 41 index4060801001988199219971988: 55 index1989: 66 index1990: 62 index1991: 51 index1992: 76 index1993: 86 index1994: 47 index1995: 46 index1996: 44 index1997: 41 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 10 values
Periodindex
199741
199644
199546
199447
199386
199276
199151
199062
198966
198855

Coles County compared with nearby places

Adams County: 122 indexChampaign County: 140 indexColes County: 41 indexCook County: 214 indexDuPage County: 126 indexEffingham County: 159 indexHamilton County: 129 indexJackson County: 45 indexJersey County: 182 indexJo Daviess County: 126 indexKane County: 147 indexLake County: 207 indexLaSalle County: 97 indexMcHenry County: 164 indexMacon County: 136 indexMacoupin County: 156 indexMadison County: 202 indexPeoria County: 143 indexRandolph County: 115 indexRock Island County: 101 indexSt. Clair County: 151 indexSangamon County: 119 indexTazewell County: 49 indexWill County: 159 indexWinnebago County: 140 index
  • Under 110
  • 110 to 130
  • 130 to 140
  • 140 to 160
  • 160 and over
  • No data
Highest daily Air Quality Index (US EPA), 1997, index. Coles 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), Coles County, 1988 to 1997) [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), Coles County, 1988 to 1997. 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/coles-county-illinois. 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), Coles County, 1988 to 1997. 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/coles-county-illinois.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Coles County, 1988 to 1997 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/coles-county-illinois (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_1997,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Coles County, 1988 to 1997}},
  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/coles-county-illinois. 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), Coles County, 1988 to 1997
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/coles-county-illinois
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/coles-county-illinois.
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 Coles County?

Highest daily Air Quality Index (US EPA) in Coles County was 41 in 1997, according to the U.S. Environmental Protection Agency. That is down 3 from 1996.

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 Coles County?

86 in 1993, the highest value since 1988 in this series.

Related statistics for Coles County

All statistics for Coles County | Coles County in figures