Air Quality Rankings for Iowa 2026

Iowa has 16 cities with EPA air quality data. Cerro Gordo, Iowa has the cleanest air with a 5-year average AQI of 18. Scott, Iowa has the highest AQI at 52.

#	City	5yr Avg AQI	Current AQI	Worst Pollutant	Trend	Grade
1	Cerro Gordo, Iowa	18	19	PM10	Worsening	B
2	Bremer, Iowa	38	42	Ozone	Worsening	C
3	Harrison, Iowa	40	44	Ozone	Worsening	C
4	Woodbury, Iowa	40	43	PM2.5	Worsening	C
5	Montgomery, Iowa	41	44	PM2.5	Improving	B
6	Lee, Iowa	42	47	PM2.5	Stable	B
7	Pottawattamie, Iowa	42	49	PM2.5	Stable	C
8	Van Buren, Iowa	43	46	PM2.5	Improving	B
9	Palo Alto, Iowa	43	46	PM2.5	Improving	B
10	Muscatine, Iowa	44	49	PM2.5	Improving	B
11	Polk, Iowa	44	52	PM2.5	Stable	C
12	Black Hawk, Iowa	45	53	PM2.5	Improving	B
13	Johnson, Iowa	48	53	PM2.5	Worsening	C
14	Linn, Iowa	49	54	PM2.5	Worsening	C
15	Clinton, Iowa	51	54	PM2.5	Improving	C
16	Scott, Iowa	52	53	PM2.5	Improving	B

Air quality data for Iowa 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

Cerro Gordo, Iowa has the best air quality in Iowa with a 5-year average AQI of 18 and a grade of B.

Iowa has 16 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 Iowa →