Milwaukee Air Quality in 2025
In 2025, Milwaukee's air quality (Milwaukee-Waukesha-West Allis, WI area) had a median daily AQI of 45 (Good) across 365 monitored days. 18 days (4.9%) reached Unhealthy for Sensitive Groups or worse, 219 were Good, and the year's peak AQI was 175 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 220 of those days. The cleanest month of 2025 was March (median AQI 30, 0 days above 100) and the worst was August (median 45, 7 days above 100, peak 160).
- Good: 60.0%
- Moderate: 35.1%
- Unhealthy for Sensitive Groups: 4.1%
- Unhealthy or worse: 0.8%
Reduce Indoor Ozone in Milwaukee
Today's main pollutant in Milwaukee is ground-level ozone (AQI 32). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How was Milwaukee's air quality in 2025?
Good on a typical day: median AQI 45, with 18 days above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 175 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 220 days.
- ✓Cleanest month: March; worst: August.
Frequently asked questions
What was the average AQI in Milwaukee in 2025?▾
EPA's Air Quality System puts Milwaukee's (Milwaukee-Waukesha-West Allis, WI) median daily AQI for 2025 at 45, which is Good. 18 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 175.
Which month had the worst air quality in Milwaukee in 2025?▾
The cleanest month of 2025 was March (median AQI 30, 0 days above 100) and the worst was August (median 45, 7 days above 100, peak 160).
Was 2025 a good or bad year for Milwaukee's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 6th cleanest by days above AQI 100. 2025's median of 45 is below the area's typical annual median of 49.
Milwaukee month by month in 2025
Milwaukee air quality month by month, 2025 (Milwaukee-Waukesha-West Allis, WI, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 38 | 0 | 76 | PM2.5 |
| February | 28 | 47 | 0 | 71 | PM2.5 |
| Marchcleanest | 31 | 30 | 0 | 85 | PM2.5 |
| April | 30 | 44 | 0 | 64 | O3 |
| May | 31 | 40 | 0 | 97 | O3 |
| June | 30 | 57 | 5 | 140 | PM2.5 |
| July | 31 | 64 | 4 | 175 | PM2.5 |
| Augustworst | 31 | 45 | 7 | 160 | O3 |
| September | 30 | 52 | 0 | 87 | O3 |
| October | 31 | 35 | 2 | 112 | O3 |
| November | 30 | 35 | 0 | 73 | PM2.5 |
| December | 31 | 53 | 0 | 67 | PM2.5 |
How 2025 compares
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 6th cleanest by days above AQI 100.
2025's median of 45 is below the area's typical annual median of 49.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Milwaukee
The latest EPA AirNow observation puts Milwaukee's AQI at 32 (O3). The figures above are multi-year annual statistics, not today's reading.
View current Milwaukee air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Milwaukee-Waukesha-West Allis, WI), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.