Air Quality Rankings for Indiana 2026

Indiana has 36 cities with EPA air quality data. Huntington, Indiana has the cleanest air with a 5-year average AQI of 31. Marion, Indiana has the highest AQI at 57.

#	City	5yr Avg AQI	Current AQI	Worst Pollutant	Trend	Grade
1	Huntington, Indiana	31	31	Ozone	Improving	B
2	Posey, Indiana	34	38	Ozone	Improving	B
3	Carroll, Indiana	34	36	Ozone	Improving	B
4	Hendricks, Indiana	34	37	Ozone	Improving	B
5	Boone, Indiana	35	37	Ozone	Improving	B
6	Brown, Indiana	35	37	Ozone	Improving	B
7	Shelby, Indiana	35	37	Ozone	Improving	B
8	Jackson, Indiana	35	35	Ozone	Improving	A
9	Morgan, Indiana	35	35	Ozone	Improving	A
10	Warrick, Indiana	36	38	Ozone	Improving	B
11	Floyd, Indiana	36	46	Ozone	Improving	A
12	Knox, Indiana	36	39	Ozone	Worsening	C
13	Wabash, Indiana	36	36	Ozone	Stable	B
14	Perry, Indiana	36	38	Ozone	Improving	B
15	Delaware, Indiana	37	40	Ozone	Stable	B
16	LaPorte, Indiana	37	39	Ozone	Improving	B
17	Henry, Indiana	38	44	PM2.5	Improving	B
18	Greene, Indiana	39	44	Ozone	Improving	B
19	Monroe, Indiana	41	40	PM2.5	Stable	C
20	Spencer, Indiana	42	43	PM2.5	Improving	B
21	Allen, Indiana	42	42	PM2.5	Improving	B
22	Bartholomew, Indiana	43	46	PM2.5	Improving	B
23	Elkhart, Indiana	43	44	PM2.5	Improving	B
24	Dubois, Indiana	43	44	PM2.5	Improving	B
25	Tippecanoe, Indiana	43	42	PM2.5	Improving	B
26	Howard, Indiana	44	45	PM2.5	Improving	B
27	Hamilton, Indiana	45	46	PM2.5	Improving	C
28	Porter, Indiana	46	48	PM2.5	Improving	C
29	Madison, Indiana	46	48	PM2.5	Stable	C
30	Whitley, Indiana	47	48	PM2.5	Stable	C
31	Vanderburgh, Indiana	49	52	PM2.5	Stable	C
32	Vigo, Indiana	49	51	PM2.5	Improving	C
33	St. Joseph, Indiana	50	51	PM2.5	Stable	C
34	Clark, Indiana	50	52	PM2.5	Stable	C
35	Lake, Indiana	53	55	PM2.5	Stable	C
36	Marion, Indiana	57	60	PM2.5	Stable	C

Air quality data for Indiana is sourced from the EPA Air Quality System (AQS), which monitors outdoor air quality at thousands of stations nationwide.
— EPA Air Quality System

Frequently Asked Questions

Huntington, Indiana has the best air quality in Indiana with a 5-year average AQI of 31 and a grade of B.

Indiana has 36 cities with EPA air quality monitoring data in our database, covering multiple years of AQI measurements.

The Air Quality Index (AQI) measures five major pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Lower AQI values indicate cleaner air — 0-50 is "Good," while 150+ is "Unhealthy."

Sources: EPA Air Quality System (AQS)

Cities ranked by 5-year average AQI (lower is better). Grades factor in average AQI, trend direction, unhealthy days, and dominant pollutant.

Cleanest Cities Nationwide →All Air Quality in Indiana →