Metro area air quality · 2025

Wausau, WI

Median AQI 36 (Good). 76.6% of monitored days rated Good across this metro's EPA monitoring network.

36
Median AQI
76.6%
Good-air days
4
Unhealthy days
60%
Cleaner than US metros

Wausau, WI posted a 2025 median AQI of 36 (Good) with 76.6% Good days

According to the U.S. EPA Air Quality System, the Wausau, WI CBSA recorded a median AQI of 36 across 342 monitored days in 2025, with 76.6% rated Good and 4 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 Wausau, WI CBSA's 76.6% Good-day share places it cleaner than 60% of US metros in 2025.
Closest median-AQI peer
Atlantic City-Hammonton, NJ (82.2% Good, median AQI 36) is the closest nationwide median-AQI peer to Wausau, WI.
2020–2025 Good-day shift
Wausau, WI's Good-day share moved -19.2 points from 2020 to 2025 (median AQI +5).
Median AQI
Median AQI: 36

Aggregated from EPA Air Quality System (2025), 342 monitored days. EPA AQS →

The verdict

Wausau, WI's median AQI 36 is in the lower (cleaner) CBSA tercile on this site. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 36 and 76.6% of 342 monitored days in the Good band.

36
median AQI · Good
76.6%
days rated Good
60%
cleaner than US metros
168
worst single reading

4 days reached Unhealthy or worse across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Wausau, WI metro's Good-day share fell from 85.0% to 77.7% between the 2024 and 2025 EPA annual releases, a change of -7.2 percentage points.
  • Wausau, WI metro's Unhealthy-category days rose from 1 to 4 between the 2024 and 2025 EPA annual releases, a change of +3 days.
  • Wausau, WI metro's peak single-day AQI rose from 151 to 168 between the 2024 and 2025 EPA annual releases, a change of +17 points.

Compared against 366 monitored days in 2024 and 337 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

Wausau, WI's median AQI 36 is in the lower (cleaner) CBSA tercile on this site. Signature read: median AQI 36 (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 36 over 342 measured days in 2025 (Good / Good). The monitored-day split lands at 262 Good (77%), 71 Moderate (21%), and 5 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 61; the highest single-day reading hit 168 (Unhealthy).

Across 2020–2025, Good-day share shifted -19.2 points and median AQI moved +5 (worsening). The annual record contains 4 days at Unhealthy or worse. Metros with comparable AQI profiles include Atlantic City-Hammonton, NJ (82.2% good, AQI 36); Barnstable Town, MA (93.7% good, AQI 36); Bemidji, MN (79.1% good, AQI 36).

Health effects of air pollution →

Air Quality Summary

Median AQI

36

Good

Good Days

76.6%

262 of 342 days

Max AQI

168

Unhealthy

Health Grade

Good

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 342 monitored days across EPA AQI categories.

Good

262

77%

Moderate

71

21%

USG

5

1%

Unhealthy

4

1%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Wausau, WI metro area's air quality is rated Good based on 76.6% good air days. There were 4 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 5 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 168. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Wausau, WI metro compare?

How Wausau, WI compares

Good-day share better than typical
Wausau, WI 76.6%
Atlantic City-Hammonton, NJ 82.2%
Typical US metro 70.6%
Median AQI better than typical
Wausau, WI 36
Atlantic City-Hammonton, NJ 36
Typical US metro 41
Unhealthy days / yr worse than typical
Wausau, WI 4
Atlantic City-Hammonton, NJ 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Wausau, WI metro. Highest Good-day share: 2020 (97.0%, 193 of 199 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 193 6 0 31
2021 191 9 0 36
2022 197 8 0 35
2023 168 39 1 41
2024 311 54 1 37
2025 262 71 4 36

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Wausau, WI (36).

Atlantic City-Hammonton, NJ

Median AQI 36 · 82.2% Good-day share

36

Barnstable Town, MA

Median AQI 36 · 93.7% Good-day share

36

Bemidji, MN

Median AQI 36 · 79.1% Good-day share

36

Claremont-Lebanon, NH-VT

Median AQI 36 · 83.6% Good-day share

36

Crestview-Fort Walton Beach-Destin, FL

Median AQI 36 · 93.9% Good-day share

36

East Stroudsburg, PA

Median AQI 36 · 88.3% Good-day share

36

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Wausau, WI's 4 (independent of median AQI).

Bakersfield, CA

4 unhealthy-or-worse days · median AQI 70

70

Bishop, CA

4 unhealthy-or-worse days · median AQI 55

55

Bismarck, ND

4 unhealthy-or-worse days · median AQI 40

40

Dickinson, ND

4 unhealthy-or-worse days · median AQI 38

38

New York-Newark-Jersey City, NY-NJ-PA

4 unhealthy-or-worse days · median AQI 53

53

St. Louis, MO-IL

4 unhealthy-or-worse days · median AQI 56

56

Frequently Asked Questions

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.
How many unhealthy air days does Wausau, WI have? ▼
In 2025, the Wausau, WI metro area recorded 4 unhealthy air days (4 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 168.
What is the air quality in the Wausau, WI metro area? ▼
The Wausau, WI metro area has a median Air Quality Index (AQI) of 36, rated "Good." 76.6% of monitored days (262 out of 342) had good air quality in 2025.
Is air quality in Wausau, WI getting better or worse? ▼
Air quality in the Wausau, WI 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 97.0% (193 of 199 days). Lowest qualifying Good-day share: 2025 at 77.7% (262 of 337 days).
How does Wausau, WI compare to other metro areas? ▼
The Wausau, WI metro has 76.6% good air days. Similar metros: Atlantic City-Hammonton, NJ (82.2% good), Barnstable Town, MA (93.7% good), Bemidji, MN (79.1% good).
What is the 90th percentile AQI for Wausau, WI? ▼
The 90th percentile AQI for the Wausau, WI metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 168 (Unhealthy).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Wausau, WI, 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, Wausau, WI · 2020–2025