Data / Share of days with good air quality (US EPA AQI) / Coles County

Share of days with good air quality (US EPA AQI) in Coles County

Share of days with good air quality (US EPA AQI) in Coles County was 100% in 1997, according to EPA. That is unchanged from 1996.

1997100%
Change on 19960 pts
Series high1001994
Series low881989

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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Share of days with good air quality (US EPA AQI) in Coles County, 1988 to 1997

87.59092.59597.5100198819901992199419971988: 98.1 %1989: 88 %1990: 94.3 %1991: 98.2 %1992: 90.2 %1993: 94.6 %1994: 100 %1995: 100 %1996: 100 %1997: 100 %8590951001988199219971988: 98.1 %1989: 88 %1990: 94.3 %1991: 98.2 %1992: 90.2 %1993: 94.6 %1994: 100 %1995: 100 %1996: 100 %1997: 100 %
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12, published 2026-07-13.
All 10 values
Period%
1997100
1996100
1995100
1994100
199394.6
199290.2
199198.2
199094.3
198988
198898.1

Coles County compared with nearby places

Adams County: 91.1 %Champaign County: 85.1 %Coles County: 100 %Cook County: 44.4 %DuPage County: 91.8 %Effingham County: 72.2 %Hamilton County: 72.3 %Jackson County: 100 %Jersey County: 66.5 %Jo Daviess County: 86.3 %Kane County: 90.1 %Lake County: 87.1 %LaSalle County: 91.8 %McHenry County: 87.6 %Macon County: 83.5 %Macoupin County: 81.6 %Madison County: 62.7 %Peoria County: 84.1 %Randolph County: 78.1 %Rock Island County: 94.8 %St. Clair County: 87.7 %Sangamon County: 89.3 %Tazewell County: 100 %Will County: 84.7 %Winnebago County: 88.8 %
  • Under 77
  • 77 to 85
  • 85 to 88
  • 88 to 92
  • 92 and over
  • No data
Share of days with good air quality (US EPA AQI), 1997, %. 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

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

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: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts (Share of days with good air quality (US EPA AQI), 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: good days as a share of days with an AQI, calculated with stored counts, Share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/coles-county-illinois. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/coles-county-illinois.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Share of days with good air quality (US EPA AQI), Coles County, 1988 to 1997 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/coles-county-illinois (Accessed: 12 October 2026).

BibTeX
@misc{environmental_share_of_days_with_1997,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/coles-county-illinois. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts: Share of days with good air quality (US EPA AQI), 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/good-air-quality-days-share/coles-county-illinois
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/coles-county-illinois.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Questions

What is the share of days with good air quality (US EPA AQI) in Coles County?

Share of days with good air quality (US EPA AQI) in Coles County was 100% in 1997, according to EPA. That is unchanged from 1996.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved by Invokely on 2026-10-12.

What was the highest share of days with good air quality (US EPA AQI) in Coles County?

100% in 1994, the highest value since 1988 in this series.

Related statistics for Coles County

All statistics for Coles County | Coles County in figures