Metro area air quality · 2025

Waterloo-Cedar Falls, IA

Median AQI 50 (Good). 52.3% of monitored days rated Good across this metro's EPA monitoring network.

50
Median AQI
52.3%
Good-air days
1
Unhealthy days
15%
Cleaner than US metros

Waterloo-Cedar Falls, IA posted a 2025 median AQI of 50 (Good) with 52.3% Good days

According to the U.S. EPA Air Quality System, the Waterloo-Cedar Falls, IA CBSA recorded a median AQI of 50 across 365 monitored days in 2025, with 52.3% 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 Waterloo-Cedar Falls, IA CBSA's 52.3% Good-day share places it cleaner than 15% of US metros in 2025.
Closest median-AQI peer
Fort Collins, CO (50.7% Good, median AQI 50) is the closest nationwide median-AQI peer to Waterloo-Cedar Falls, IA.
2020–2025 Good-day shift
Waterloo-Cedar Falls, IA's Good-day share moved -10.8 points from 2020 to 2025 (median AQI +6).
Median AQI
Median AQI: 50

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Waterloo-Cedar Falls, IA lands in the lower Good-day tercile (52.3% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, among the more polluted US metros, with a median AQI of 50 and 52.3% of 365 monitored days in the Good band.

50
median AQI · Good
52.3%
days rated Good
15%
cleaner than US metros
158
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
  • Waterloo-Cedar Falls, IA metro's peak single-day AQI rose from 87 to 158 between the 2024 and 2025 EPA annual releases, a change of +71 points.
  • Waterloo-Cedar Falls, IA metro's Good-day share fell from 55.1% to 52.6% between the 2024 and 2025 EPA annual releases, a change of -2.5 percentage points.
  • Waterloo-Cedar Falls, 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 365 monitored days in 2024 and 363 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

Waterloo-Cedar Falls, IA lands in the lower Good-day tercile (52.3% Good), a thinner clean-air share than most CBSA peers here. Signature read: 52.3% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 50 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 191 Good (52%), 171 Moderate (47%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 66; the highest single-day reading hit 158 (Unhealthy).

Across 2020–2025, Good-day share shifted -10.8 points and median AQI moved +6 (worsening). The annual record contains 1 day at Unhealthy or worse. Metros with comparable AQI profiles include Fort Collins, CO (50.7% good, AQI 50); Madera, CA (50.4% good, AQI 50); Merced, CA (51.0% good, AQI 50).

Health effects of air pollution →

Air Quality Summary

Median AQI

50

Good

Good Days

52.3%

191 of 365 days

Max AQI

158

Unhealthy

Health Grade

Moderate

90th pct: 66

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

191

52%

Moderate

171

47%

USG

2

1%

Unhealthy

1

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Waterloo-Cedar Falls, IA metro area's air quality is rated Moderate based on 52.3% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 2 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 158. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Waterloo-Cedar Falls, IA metro compare?

How Waterloo-Cedar Falls, IA compares

Good-day share worse than typical
Waterloo-Cedar Falls, IA 52.3%
Fort Collins, CO 50.7%
Typical US metro 70.6%
Median AQI worse than typical
Waterloo-Cedar Falls, IA 50
Fort Collins, CO 50
Typical US metro 41
Unhealthy days / yr about typical
Waterloo-Cedar Falls, IA 1
Fort Collins, CO 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Waterloo-Cedar Falls, IA metro. Highest Good-day share: 2020 (63.4%, 232 of 366 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 232 134 0 44
2021 203 162 0 48
2022 226 139 0 46
2023 156 193 4 53
2024 201 164 0 48
2025 191 171 1 50

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Waterloo-Cedar Falls, IA (50).

Fort Collins, CO

Median AQI 50 · 50.7% Good-day share

50

Madera, CA

Median AQI 50 · 50.4% Good-day share

50

Merced, CA

Median AQI 50 · 51.0% Good-day share

50

Nashville-Davidson--Murfreesboro--Franklin, TN

Median AQI 50 · 51.2% Good-day share

50

Oxnard-Thousand Oaks-Ventura, CA

Median AQI 50 · 52.0% Good-day share

50

Reno, NV

Median AQI 50 · 50.1% Good-day share

50

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Waterloo-Cedar Falls, 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

Frequently Asked Questions

How many unhealthy air days does Waterloo-Cedar Falls, IA have? ▼
In 2025, the Waterloo-Cedar Falls, IA metro area recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 158.
What is the air quality in the Waterloo-Cedar Falls, IA metro area? ▼
The Waterloo-Cedar Falls, IA metro area has a median Air Quality Index (AQI) of 50, rated "Good." 52.3% of monitored days (191 out of 365) had good air quality in 2025.
Is air quality in Waterloo-Cedar Falls, IA getting better or worse? ▼
Air quality in the Waterloo-Cedar Falls, IA metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 63.4% (232 of 366 days). Lowest qualifying Good-day share: 2023 at 44.2% (156 of 353 days).
What does AQI 50 mean for health? ▼
An AQI of 50 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does Waterloo-Cedar Falls, IA compare to other metro areas? ▼
The Waterloo-Cedar Falls, IA metro has 52.3% good air days. Similar metros: Fort Collins, CO (50.7% good), Madera, CA (50.4% good), Merced, CA (51.0% good).
What is the 90th percentile AQI for Waterloo-Cedar Falls, IA? ▼
The 90th percentile AQI for the Waterloo-Cedar Falls, IA metro area is 66, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 158 (Unhealthy).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Waterloo-Cedar Falls, IA, 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, Waterloo-Cedar Falls, IA · 2020–2025