Ann Arbor Air Quality in 2019
In 2019, Ann Arbor's air quality (Ann Arbor, MI area) had a median daily AQI of 44 (Good) across 365 monitored days. 0 days (0.0%) reached Unhealthy for Sensitive Groups or worse, 248 were Good, and the year's peak AQI was 89 (Moderate). Fine particulate matter (PM2.5) set the daily AQI on 191 of those days. The cleanest month of 2019 was August (median AQI 38, 0 days above 100) and the worst was December (median 53, 0 days above 100, peak 83).
- Good: 67.9%
- Moderate: 32.1%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Extra Protection for Ann Arbor Homes
Air quality in Ann Arbor is moderate (AQI 56), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How was Ann Arbor's air quality in 2019?
Good on a typical day: median AQI 44, with 0 days above AQI 100 out of 365 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2019: 89 (Moderate).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 191 days.
- ✓Cleanest month: August; worst: December.
Frequently asked questions
What was the average AQI in Ann Arbor in 2019?▾
EPA's Air Quality System puts Ann Arbor's (Ann Arbor, MI) median daily AQI for 2019 at 44, which is Good. 0 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 89.
Which month had the worst air quality in Ann Arbor in 2019?▾
The cleanest month of 2019 was August (median AQI 38, 0 days above 100) and the worst was December (median 53, 0 days above 100, peak 83).
Was 2019 a good or bad year for Ann Arbor's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100. 2019's median of 44 is in line with the area's typical annual median of 44.
Ann Arbor month by month in 2019
Ann Arbor air quality month by month, 2019 (Ann Arbor, MI, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 51 | 0 | 63 | PM2.5 |
| February | 28 | 47 | 0 | 89 | PM2.5 |
| March | 31 | 44 | 0 | 70 | O3 |
| April | 30 | 44 | 0 | 61 | O3 |
| May | 31 | 39 | 0 | 58 | O3 |
| June | 30 | 49 | 0 | 80 | O3 |
| July | 31 | 48 | 0 | 87 | O3 |
| Augustcleanest | 31 | 38 | 0 | 56 | O3 |
| September | 30 | 41 | 0 | 64 | PM2.5 |
| October | 31 | 40 | 0 | 71 | PM2.5 |
| November | 30 | 49 | 0 | 78 | PM2.5 |
| Decemberworst | 31 | 53 | 0 | 83 | PM2.5 |
How 2019 compares
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100.
2019's median of 44 is in line with 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 56 (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.