Metro area air quality · 2025

Iowa City, IA

Median AQI 37 (Good). 70.1% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
70.1%
Good-air days
1
Unhealthy days
46%
Cleaner than US metros

Iowa City, IA posted a 2025 median AQI of 37 (Good) with 70.1% Good days

According to the U.S. EPA Air Quality System, the Iowa City, IA CBSA recorded a median AQI of 37 across 365 monitored days in 2025, with 70.1% rated Good and 1 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Iowa City, IA CBSA's 70.1% Good-day share places it cleaner than 46% of US metros in 2025.
Closest median-AQI peer
Alexandria, LA (73.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Iowa City, IA.
2020–2025 Good-day shift
Iowa City, IA's Good-day share moved +13.4 points from 2020 to 2025 (median AQI -10).
Median AQI
Median AQI: 37

Aggregated from EPA Air Quality System (2025), 365 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 37 with 70.1% of 365 monitored days in the Good band.

37
median AQI · Good
70.1%
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.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Iowa City, IA metro's peak single-day AQI rose from 83 to 159 between the 2024 and 2025 EPA annual releases, a change of +76 points.
  • Iowa City, IA metro's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.

Compared against 366 monitored days in 2024 and 362 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Insights: Iowa City, IA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 365 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 256 Good days (70%), 105 Moderate (29%), and 3 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 159 (Unhealthy). Metro residents averaged roughly 21.0 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +13.4 points and the median AQI moved -10 points, which classifies the multi-year trajectory as improving. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Alexandria, LA (73.7% good, AQI 37); Athens, TN (78.2% good, AQI 37); Bennington, VT (83.6% good, AQI 37).

Air Quality Summary

Median AQI

37

Good

Good Days

70.1%

256 of 365 days

Max AQI

159

Unhealthy

Health Grade

Moderate

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

256

70%

Moderate

105

29%

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 70.1% 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 typical
Iowa City, IA 70.1%
Alexandria, LA 73.7%
Typical US metro 70.6%
Median AQI better than typical
Iowa City, IA 37
Alexandria, LA 37
Typical US metro 41
Unhealthy days / yr about typical
Iowa City, IA 1
Alexandria, LA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is improving in the Iowa City, IA metro. Highest Good-day share: 2024 (70.8%, 259 of 366 monitored 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 256 105 1 37

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Iowa City, IA (37).

Alexandria, LA

Median AQI 37 · 73.7% Good-day share

37

Athens, TN

Median AQI 37 · 78.2% Good-day share

37

Bennington, VT

Median AQI 37 · 83.6% Good-day share

37

Blacksburg-Christiansburg-Radford, VA

Median AQI 37 · 94.4% Good-day share

37

Cadillac, MI

Median AQI 37 · 86.0% Good-day share

37

Chambersburg-Waynesboro, PA

Median AQI 37 · 91.5% Good-day share

37

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Iowa City, IA's 1 (independent of median AQI).

Ann Arbor, MI

1 unhealthy-or-worse days · median AQI 41

41

Bangor, ME

1 unhealthy-or-worse days · median AQI 33

33

Baraboo, WI

1 unhealthy-or-worse days · median AQI 35

35

Bartlesville, OK

1 unhealthy-or-worse days · median AQI 44

44

Beaumont-Port Arthur, TX

1 unhealthy-or-worse days · median AQI 52

52

Beaver Dam, WI

1 unhealthy-or-worse days · median AQI 40

40

More Air Quality Data

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

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

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 37, rated "Good." 70.1% of monitored days (256 out of 365) 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 across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2024 at 70.8% (259 of 366 days). Lowest qualifying Good-day share: 2023 at 39.5% (143 of 362 days).
What does AQI 37 mean for health? ▼
An AQI of 37 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 61, 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 70.1% good air days. Similar metros: Alexandria, LA (73.7% good), Athens, TN (78.2% good), Bennington, VT (83.6% 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.

Read our methodology , how this data is sourced, computed, and verified.

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

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Every figure on PlainAirData 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.