Data / Rankings / Median Air Quality Index (US EPA) / Counties in Indiana

Counties in Indiana by median Air Quality Index (US EPA)

Marion County had the highest median Air Quality Index (US EPA) of 42 counties in 2002, at 68. Jasper County had the lowest, at 14. The median was 54. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest68Marion County
Lowest14Jasper County
Median5442 counties

Map of counties, 2002

Allen County: 55 indexBoone County: 54 indexCarroll County: 54 indexClark County: 58 indexDaviess County: 15 indexDeKalb County: 20 indexDelaware County: 54 indexDubois County: 60 indexElkhart County: 56 indexFloyd County: 53 indexGibson County: 29 indexGreene County: 54 indexHamilton County: 49 indexHancock County: 49 indexHendricks County: 50 indexHenry County: 58 indexHoward County: 59 indexHuntington County: 47 indexJackson County: 54 indexJasper County: 14 indexJohnson County: 54 indexKnox County: 42 indexLake County: 66 indexLaPorte County: 55 indexMadison County: 61 indexMarion County: 68 indexMorgan County: 58 indexPerry County: 20 indexPorter County: 43 indexPosey County: 51 indexPutnam County: 18 indexSt. Joseph County: 56 indexShelby County: 58 indexSpencer County: 57 indexTippecanoe County: 59 indexVanderburgh County: 54 indexVigo County: 58 indexWabash County: 36 indexWarrick County: 58 indexWashington County: 53 indexWayne County: 17 indexWhitley County: 19 index
  • Under 27
  • 27 to 50
  • 50 to 54
  • 54 to 56
  • 56 to 58
  • 58 and over
  • No data
index, 2002. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2002

Marion County: 68 indexMarion County68Lake County: 66 indexLake County66Madison County: 61 indexMadison County61Dubois County: 60 indexDubois County60Howard County: 59 indexHoward County59Tippecanoe County: 59 indexTippecanoe County59Clark County: 58 indexClark County58Henry County: 58 indexHenry County58Morgan County: 58 indexMorgan County58Shelby County: 58 indexShelby County58Vigo County: 58 indexVigo County58Warrick County: 58 indexWarrick County58Spencer County: 57 indexSpencer County57Elkhart County: 56 indexElkhart County56St. Joseph County: 56 indexSt. Joseph County56Allen County: 55 indexAllen County55LaPorte County: 55 indexLaPorte County55Boone County: 54 indexBoone County54Carroll County: 54 indexCarroll County54Delaware County: 54 indexDelaware County54Greene County: 54 indexGreene County54Jackson County: 54 indexJackson County54Johnson County: 54 indexJohnson County54Vanderburgh County: 54 indexVanderburgh County54Floyd County: 53 indexFloyd County53Washington County: 53 indexWashington County53Posey County: 51 indexPosey County51Hendricks County: 50 indexHendricks County50Hamilton County: 49 indexHamilton County49Hancock County: 49 indexHancock County49Huntington County: 47 indexHuntington County47Porter County: 43 indexPorter County43Knox County: 42 indexKnox County42Wabash County: 36 indexWabash County36Gibson County: 29 indexGibson County29DeKalb County: 20 indexDeKalb County20Perry County: 20 indexPerry County20Whitley County: 19 indexWhitley County19Putnam County: 18 indexPutnam County18Wayne County: 17 indexWayne County17Daviess County: 15 indexDaviess County15Jasper County: 14 indexJasper County14Marion County: 68 indexMarion County68Lake County: 66 indexLake County66Madison County: 61 indexMadison County61Dubois County: 60 indexDubois County60Howard County: 59 indexHoward County59Tippecanoe County: 59 indexTippecanoe County59Clark County: 58 indexClark County58Henry County: 58 indexHenry County58Morgan County: 58 indexMorgan County58Shelby County: 58 indexShelby County58Vigo County: 58 indexVigo County58Warrick County: 58 indexWarrick County58Spencer County: 57 indexSpencer County57Elkhart County: 56 indexElkhart County56St. Joseph County: 56 indexSt. Joseph County56Allen County: 55 indexAllen County55LaPorte County: 55 indexLaPorte County55Boone County: 54 indexBoone County54Carroll County: 54 indexCarroll County54Delaware County: 54 indexDelaware County54Greene County: 54 indexGreene County54Jackson County: 54 indexJackson County54Johnson County: 54 indexJohnson County54Vanderburgh County: 54 indexVanderburgh County54Floyd County: 53 indexFloyd County53Washington County: 53 indexWashington County53Posey County: 51 indexPosey County51Hendricks County: 50 indexHendricks County50Hamilton County: 49 indexHamilton County49Hancock County: 49 indexHancock County49Huntington County: 47 indexHuntington County47Porter County: 43 indexPorter County43Knox County: 42 indexKnox County42Wabash County: 36 indexWabash County36Gibson County: 29 indexGibson County29DeKalb County: 20 indexDeKalb County20Perry County: 20 indexPerry County20Whitley County: 19 indexWhitley County19Putnam County: 18 indexPutnam County18Wayne County: 17 indexWayne County17Daviess County: 15 indexDaviess County15Jasper County: 14 indexJasper County14
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2002
index		Change on 2001
1Marion County68-1
2Lake County66-4
3Madison County61+2
4Dubois County60+3
5Howard County59-1
5Tippecanoe County59-1
7Clark County580
7Henry County580
7Morgan County58+9
7Shelby County58+4
7Vigo County580
7Warrick County58+8
13Spencer County57+42
14Elkhart County56+11
14St. Joseph County56+13
16Allen County55+12
16LaPorte County550
18Boone County54+6
18Carroll County54+7
18Delaware County54-3
18Greene County540
18Jackson County54+5
18Johnson County54+5
18Vanderburgh County54+12
25Floyd County53+3
25Washington County53-2
27Posey County51+2
28Hendricks County50+2
29Hamilton County490
29Hancock County490
31Huntington County47+1
32Porter County43+1
33Knox County42-2
34Wabash County360
35Gibson County29-1
36DeKalb County20+4
36Perry County20-29
38Whitley County19+2
39Putnam County18-2
40Wayne County17+2
41Daviess County15-1
42Jasper County14-1

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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: median 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: median daily AQI (Counties in Indiana by median Air Quality Index (US EPA), 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: median daily AQI, Counties in Indiana by median Air Quality Index (US EPA), 2002. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/indiana-counties?period=2002. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Indiana by median Air Quality Index (US EPA), 2002. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/indiana-counties?period=2002.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Indiana by median Air Quality Index (US EPA), 2002 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/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: median daily AQI: Counties in Indiana by median Air Quality Index (US EPA), 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/median-air-quality-index/indiana-counties?period=2002. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median 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: median daily AQI: Counties in Indiana by median Air Quality Index (US EPA), 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/median-air-quality-index/indiana-counties?period=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/indiana-counties?period=2002.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Indiana by median Air Quality Index (US EPA) using official data, and cite the source.
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Questions

Which county has the highest median Air Quality Index (US EPA)?

Marion County, with 68 in 2002, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Jasper County, with 14 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: median daily AQI. Retrieved 2026-10-12. 11 counties have no value for 2002 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Indiana: more rankings