Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI)

Warrick County had the highest share of days unhealthy for sensitive groups or worse (US EPA AQI) of 42 counties in 2002, at 24.6%. Whitley County had the lowest, at 0%. The median was 12.3%. Source: EPA.

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Highest24.6Warrick County
Median12.342 counties

Map of counties, 2002

Allen County: 9.6 %Boone County: 20.8 %Carroll County: 17 %Clark County: 15.7 %Daviess County: 0 %DeKalb County: 0 %Delaware County: 13.9 %Dubois County: 2.6 %Elkhart County: 14.5 %Floyd County: 12.2 %Gibson County: 3.6 %Greene County: 20.2 %Hamilton County: 19.1 %Hancock County: 20.8 %Hendricks County: 18.9 %Henry County: 0.9 %Howard County: 1.7 %Huntington County: 13.1 %Jackson County: 18 %Jasper County: 0 %Johnson County: 19.7 %Knox County: 8.9 %Lake County: 11.8 %LaPorte County: 16.8 %Madison County: 19.2 %Marion County: 13.2 %Morgan County: 20.8 %Perry County: 0 %Porter County: 10.4 %Posey County: 18.9 %Putnam County: 0 %St. Joseph County: 12.3 %Shelby County: 19.7 %Spencer County: 0 %Tippecanoe County: 1.1 %Vanderburgh County: 12.1 %Vigo County: 12.8 %Wabash County: 8 %Warrick County: 24.6 %Washington County: 0 %Wayne County: 0 %Whitley County: 0 %
  • Under 6.5
  • 6.5 to 12
  • 12 to 16
  • 16 to 19
  • 19 and over
  • No data
%, 2002. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2002

Warrick County: 24.6 %Warrick County24.6Boone County: 20.8 %Boone County20.8Hancock County: 20.8 %Hancock County20.8Morgan County: 20.8 %Morgan County20.8Greene County: 20.2 %Greene County20.2Johnson County: 19.7 %Johnson County19.7Shelby County: 19.7 %Shelby County19.7Madison County: 19.2 %Madison County19.2Hamilton County: 19.1 %Hamilton County19.1Hendricks County: 18.9 %Hendricks County18.9Posey County: 18.9 %Posey County18.9Jackson County: 18 %Jackson County18Carroll County: 17 %Carroll County17LaPorte County: 16.8 %LaPorte County16.8Clark County: 15.7 %Clark County15.7Elkhart County: 14.5 %Elkhart County14.5Delaware County: 13.9 %Delaware County13.9Marion County: 13.2 %Marion County13.2Huntington County: 13.1 %Huntington County13.1Vigo County: 12.8 %Vigo County12.8St. Joseph County: 12.3 %St. Joseph County12.3Floyd County: 12.2 %Floyd County12.2Vanderburgh County: 12.1 %Vanderburgh County12.1Lake County: 11.8 %Lake County11.8Porter County: 10.4 %Porter County10.4Allen County: 9.6 %Allen County9.6Knox County: 8.9 %Knox County8.9Wabash County: 8 %Wabash County8Gibson County: 3.6 %Gibson County3.6Dubois County: 2.6 %Dubois County2.6Howard County: 1.7 %Howard County1.7Tippecanoe County: 1.1 %Tippecanoe County1.1Henry County: 0.9 %Henry County0.9Daviess County: 0 %Daviess County0DeKalb County: 0 %DeKalb County0Jasper County: 0 %Jasper County0Perry County: 0 %Perry County0Putnam County: 0 %Putnam County0Spencer County: 0 %Spencer County0Washington County: 0 %Washington County0Wayne County: 0 %Wayne County0Whitley County: 0 %Whitley County0Warrick County: 24.6 %Warrick County24.6Boone County: 20.8 %Boone County20.8Hancock County: 20.8 %Hancock County20.8Morgan County: 20.8 %Morgan County20.8Greene County: 20.2 %Greene County20.2Johnson County: 19.7 %Johnson County19.7Shelby County: 19.7 %Shelby County19.7Madison County: 19.2 %Madison County19.2Hamilton County: 19.1 %Hamilton County19.1Hendricks County: 18.9 %Hendricks County18.9Posey County: 18.9 %Posey County18.9Jackson County: 18 %Jackson County18Carroll County: 17 %Carroll County17LaPorte County: 16.8 %LaPorte County16.8Clark County: 15.7 %Clark County15.7Elkhart County: 14.5 %Elkhart County14.5Delaware County: 13.9 %Delaware County13.9Marion County: 13.2 %Marion County13.2Huntington County: 13.1 %Huntington County13.1Vigo County: 12.8 %Vigo County12.8St. Joseph County: 12.3 %St. Joseph County12.3Floyd County: 12.2 %Floyd County12.2Vanderburgh County: 12.1 %Vanderburgh County12.1Lake County: 11.8 %Lake County11.8Porter County: 10.4 %Porter County10.4Allen County: 9.6 %Allen County9.6Knox County: 8.9 %Knox County8.9Wabash County: 8 %Wabash County8Gibson County: 3.6 %Gibson County3.6Dubois County: 2.6 %Dubois County2.6Howard County: 1.7 %Howard County1.7Tippecanoe County: 1.1 %Tippecanoe County1.1Henry County: 0.9 %Henry County0.9Daviess County: 0 %Daviess County0DeKalb County: 0 %DeKalb County0Jasper County: 0 %Jasper County0Perry County: 0 %Perry County0Putnam County: 0 %Putnam County0Spencer County: 0 %Spencer County0Washington County: 0 %Washington County0Wayne County: 0 %Wayne County0Whitley County: 0 %Whitley County0
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2002 (%)Change on 2001
1Warrick County24.6+12.6 pts
2Boone County20.8+4.4 pts
2Hancock County20.8+2.8 pts
2Morgan County20.8+7.1 pts
5Greene County20.2+1.7 pts
6Johnson County19.7+8.5 pts
6Shelby County19.7+1.7 pts
8Madison County19.2+8.3 pts
9Hamilton County19.1+1.6 pts
10Hendricks County18.9+4.1 pts
10Posey County18.9+8.3 pts
12Jackson County18+8.2 pts
13Carroll County17+8.1 pts
14LaPorte County16.8+4.8 pts
15Clark County15.7+4.7 pts
16Elkhart County14.5+12.6 pts
17Delaware County13.9+3 pts
18Marion County13.2+0.6 pts
19Huntington County13.1+4.9 pts
20Vigo County12.8+1.7 pts
21St. Joseph County12.3+5.2 pts
22Floyd County12.2+8.3 pts
23Vanderburgh County12.1+9.1 pts
24Lake County11.8-6 pts
25Porter County10.4+2.6 pts
26Allen County9.6+4.1 pts
27Knox County8.9+2.3 pts
28Wabash County8+4.7 pts
29Gibson County3.6+3.3 pts
30Dubois County2.6+0.5 pts
31Howard County1.7-1.1 pts
32Tippecanoe County1.1-1.5 pts
33Henry County0.9-0.9 pts
34Daviess County00 pts
34DeKalb County00 pts
34Jasper County00 pts
34Perry County0-15 pts
34Putnam County00 pts
34Spencer County00 pts
34Washington County0-3 pts
34Wayne County00 pts
34Whitley County00 pts

Other periods

About this ranking

Days with a daily Air Quality Index above 100 (unhealthy for sensitive groups, unhealthy, very unhealthy or hazardous) 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; the counts are stored with each value.

Use the share rather than the number of days to compare counties, since the days with an AQI differ. 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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 11 counties with data in other periods have no value for 2002 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts (Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002) [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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_indiana_by_2002,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002}},
  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/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2002
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/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/indiana-counties?period=2002.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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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Rank Counties in Indiana by share of days unhealthy for sensitive groups or worse (US EPA AQI) using official data, and cite the source.
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Questions

Which county has the highest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Warrick County, with 24.6% in 2002, according to EPA.

Which county has the lowest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Whitley County, with 0% in 2002.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 11 counties have no value for 2002 and are not ranked.

Share of days unhealthy for sensitive groups or worse (US EPA AQI): other rankings

Counties in Indiana: more rankings