Ann Arbor Air Quality in August
Across 2019–2025, Ann Arbor's August air quality had a median AQI of 44 (Good) over 217 monitored days in the Ann Arbor, MI area. 0.5% of August days (1 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 50.7% of days. The cleanest August on record here was 2019 (median AQI 38, 0 days above 100) and the worst was 2025 (median 44, 1 day above 100, peak AQI 125).
- Good: 63.1%
- Moderate: 36.4%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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.
Recommended: Levoit Core 400S — True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Ann Arbor in August?
Good on a typical day: median AQI 44 across 2019–2025, with 0.5% of August days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓63.1% of August days were Good (AQI 0–50), 36.4% Moderate (51–100).
- ✓1 day of 217 reached AQI 101+; the August peak was 125.
- ✓Best August: 2019; worst August: 2025.
Frequently asked questions
What is the air quality like in Ann Arbor in August?▾
Across 2019–2025, the median daily AQI in Ann Arbor in August was 44 (Good). 63.1% of days were Good, 36.4% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is August a good time for outdoor exercise in Ann Arbor?▾
A typical August day in Ann Arbor sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of August days reached AQI 101+ in 2019–2025.
Which pollutant causes Ann Arbor's August air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 50.7% of August days in Ann Arbor. The highest August AQI recorded in 2019–2025 was 125 (Unhealthy for Sensitive Groups), in 2025.
Ann Arbor August air quality, year by year
Ann Arbor August air quality by year (Ann Arbor, MI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 38 | 0 | 56 | O3 |
| 2020 | 31 | 44 | 0 | 80 | PM2.5 |
| 2021 | 31 | 52 | 0 | 80 | PM2.5 |
| 2022 | 31 | 41 | 0 | 55 | O3 |
| 2023 | 31 | 52 | 0 | 84 | PM2.5 |
| 2024 | 31 | 41 | 0 | 62 | O3 |
| 2025worst | 31 | 44 | 1 | 125 | O3 |
What August air means in Ann Arbor
A typical August day in Ann Arbor sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of August days reached AQI 101+ in 2019–2025.
August's median AQI of 44 is in line with Ann Arbor's whole-year median of 44, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Ann Arbor runs in line with the national August norm; 0.5% of its August days topped AQI 100 versus 3.5% nationally (below average).
August is part of Ann Arbor's summer season (June, July, August); the summer page pools all three months.
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 month 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.