Ann Arbor Air Quality in 2025
In 2025, Ann Arbor's air quality (Ann Arbor, MI area) had a median daily AQI of 41 (Good) across 365 monitored days. 8 days (2.2%) reached Unhealthy for Sensitive Groups or worse, 253 were Good, and the year's peak AQI was 152 (Unhealthy). Ground-level ozone set the daily AQI on 229 of those days. The cleanest month of 2025 was October (median AQI 33, 0 days above 100) and the worst was June (median 52, 3 days above 100, peak 152).
- Good: 69.3%
- Moderate: 28.5%
- Unhealthy for Sensitive Groups: 1.9%
- Unhealthy or worse: 0.3%
Improve Indoor Air Quality
Even with good outdoor air in Ann Arbor, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
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How was Ann Arbor's air quality in 2025?
Good on a typical day: median AQI 41, with 8 days above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 152 (Unhealthy).
- ✓Ground-level ozone was the main pollutant on 229 days.
- ✓Cleanest month: October; worst: June.
Frequently asked questions
What was the average AQI in Ann Arbor in 2025?▾
EPA's Air Quality System puts Ann Arbor's (Ann Arbor, MI) median daily AQI for 2025 at 41, which is Good. 8 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 152.
Which month had the worst air quality in Ann Arbor in 2025?▾
The cleanest month of 2025 was October (median AQI 33, 0 days above 100) and the worst was June (median 52, 3 days above 100, peak 152).
Was 2025 a good or bad year for Ann Arbor'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 41 is below the area's typical annual median of 44.
Ann Arbor month by month in 2025
Ann Arbor air quality month by month, 2025 (Ann Arbor, MI, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 34 | 0 | 75 | O3 |
| February | 28 | 40 | 0 | 68 | O3 |
| March | 31 | 40 | 0 | 54 | O3 |
| April | 30 | 45 | 0 | 93 | O3 |
| May | 31 | 39 | 0 | 100 | O3 |
| Juneworst | 30 | 52 | 3 | 152 | PM2.5 |
| July | 31 | 53 | 2 | 136 | PM2.5 |
| August | 31 | 44 | 1 | 125 | O3 |
| September | 30 | 44 | 2 | 108 | O3 |
| Octobercleanest | 31 | 33 | 0 | 87 | O3 |
| November | 30 | 33 | 0 | 68 | PM2.5 |
| December | 31 | 43 | 0 | 69 | 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 41 is below the area's typical annual median of 44.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Ann Arbor
The latest EPA AirNow observation puts Ann Arbor's AQI at 29 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Ann Arbor air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Ann Arbor, MI), 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.