Metro area air quality · 2025

Iowa City, IA

Median AQI 36 (Good). 71.0% of monitored days rated Good across this metro's EPA monitoring network.

36
Median AQI
71.0%
Good-air days
1
Unhealthy days
46%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 304 monitored days. EPA AQS →

The verdict

The Iowa City, IA metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 36 with 71.0% of 304 monitored days in the Good band.

36
median AQI · Good
71.0%
days rated Good
46%
cleaner than US metros
159
worst single reading

1 day reached Unhealthy or worse across the metro's monitors in 2025.

Insights: Iowa City, IA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 36 over 304 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 216 Good days (71%), 84 Moderate (28%), and 3 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 62 while the highest single-day reading hit 159 (Unhealthy). Metro residents averaged roughly 21.3 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by +9 and the median AQI moved -11 points, which classifies the multi-year trajectory as improving. The metro recorded 1 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Augusta-Waterville, ME (83.5% good, AQI 36); Beatrice, NE (74.0% good, AQI 36); Eureka-Arcata-Fortuna, CA (83.2% good, AQI 36).

Air Quality Summary

Median AQI

36

Good

Good Days

71.0%

216 of 304 days

Max AQI

159

Unhealthy

Health Grade

Moderate

90th pct: 62

AQI Day Breakdown (2025)

Distribution of 304 monitored days across EPA AQI categories.

Good

216

71%

Moderate

84

28%

USG

3

1%

Unhealthy

1

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Iowa City, IA metro area's air quality is rated Moderate based on 71.0% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 3 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 159. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Iowa City, IA metro compare?

How Iowa City, IA compares

Good-day share about average
Iowa City, IA 71.0%
Augusta-Waterville, ME 83.5%
US average 71.3%
Median AQI better than US avg
Iowa City, IA 36
Augusta-Waterville, ME 36
US average 41
Unhealthy days / yr about average
Iowa City, IA 1
Augusta-Waterville, ME 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the Iowa City, IA metro. Best year: 2024 (259 good days).

Year Good Moderate Unhealthy Median AQI
2020 207 154 0 47
2021 172 190 0 52
2022 223 141 0 44
2023 143 216 3 53
2024 259 107 0 39
2025 216 84 1 36

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Iowa City, IA.

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Iowa City, IA metro area?
The Iowa City, IA metro area has a median Air Quality Index (AQI) of 36, rated "Good." 71.0% of monitored days (216 out of 304) had good air quality in 2025.
How many unhealthy air days does Iowa City, IA have?
In 2025, the Iowa City, IA metro area recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 159.
Is air quality in Iowa City, IA getting better or worse?
Air quality in the Iowa City, IA metro is improving based on 5-year trends (2020-2025). Best year: 2024 with 259 good days. Worst year: 2023 with 143 good days.
What does AQI 36 mean for health?
An AQI of 36 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Iowa City, IA?
The 90th percentile AQI for the Iowa City, IA metro area is 62, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 159 (Unhealthy).
How does Iowa City, IA compare to other metro areas?
The Iowa City, IA metro has 71.0% good air days. Similar metros: Augusta-Waterville, ME (83.5% good), Beatrice, NE (74.0% good), Eureka-Arcata-Fortuna, CA (83.2% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. See our methodology for how AQI, median, and coverage figures are computed.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.