Counties in Indiana by highest daily Air Quality Index (US EPA)

Hendricks County had the highest highest daily Air Quality Index (US EPA) of 40 counties in 2000, at 204. Jasper County had the lowest, at 40. The median was 160. Source: the U.S. Environmental Protection Agency.

Highest204Hendricks County

Lowest40Jasper County

Median16040 counties

Map of counties, 2000

Under 86
86 to 130
130 to 160
160 to 170
170 to 180
180 and over
No data

index, 2000. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2000

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2000 index	Change on 1999
1	Hendricks County	204	+38
2	LaPorte County	195	-8
3	Porter County	190	-10
4	Hamilton County	187	-8
5	Allen County	182	+10
5	Hancock County	182	-3
5	Marion County	182	-8
8	Shelby County	179	n/a
9	Greene County	174	n/a
9	Wabash County	174	-13
11	Perry County	172	-28
12	Huntington County	169	n/a
12	Morgan County	169	-10
12	Posey County	169	-31
15	Boone County	166	n/a
15	St. Joseph County	166	-8
17	Jackson County	164	n/a
17	Johnson County	164	-21
17	Lake County	164	-28
17	Madison County	164	-21
21	Clark County	156	-21
22	Knox County	154	-23
22	Vigo County	154	-12
24	Vanderburgh County	150	-40
25	Warrick County	136	-54
26	Delaware County	134	+44
27	Dubois County	133	+81
27	Floyd County	133	-71
29	Elkhart County	126	-14
30	Spencer County	120	+40
31	Gibson County	112	-49
32	Tippecanoe County	111	-1
33	Howard County	101	-15
34	Henry County	71	n/a
35	Bartholomew County	58	n/a
36	Daviess County	56	n/a
37	DeKalb County	55	+1
37	Putnam County	55	n/a
39	Wayne County	50	n/a
40	Jasper County	40	-11

Other periods

About this ranking

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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 13 counties with data in other periods have no value for 2000 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: 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 (Counties in Indiana by highest daily Air Quality Index (US EPA), 2000) [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, Counties in Indiana by highest daily Air Quality Index (US EPA), 2000. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/indiana-counties?period=2000. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Indiana by highest daily Air Quality Index (US EPA), 2000. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/indiana-counties?period=2000.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Indiana by highest daily Air Quality Index (US EPA), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/indiana-counties?period=2000 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_indiana_by_2000,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Indiana by highest daily Air Quality Index (US EPA), 2000}},
  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/highest-daily-air-quality-index/indiana-counties?period=2000. 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: Counties in Indiana by highest daily Air Quality Index (US EPA), 2000
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/highest-daily-air-quality-index/indiana-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/indiana-counties?period=2000.
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

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

Hendricks County, with 204 in 2000, according to the U.S. Environmental Protection Agency.

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

Jasper County, with 40 in 2000.

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: highest daily AQI. Retrieved 2026-10-12. 13 counties have no value for 2000 and are not ranked.