Detroit Air Quality in 2021
In 2021, Detroit's air quality (Detroit-Warren-Dearborn, MI area) had a median daily AQI of 59 (Moderate) across 365 monitored days. 9 days (2.5%) reached Unhealthy for Sensitive Groups or worse, 85 were Good, and the year's peak AQI was 140 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 307 of those days. The cleanest month of 2021 was September (median AQI 49, 0 days above 100) and the worst was June (median 60, 4 days above 100, peak 119).
- Good: 23.3%
- Moderate: 74.2%
- Unhealthy for Sensitive Groups: 2.5%
- Unhealthy or worse: 0.0%
Extra Protection for Detroit Homes
Air quality in Detroit 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
As an Amazon Associate, we earn from qualifying purchases.
How was Detroit's air quality in 2021?
Moderate on a typical day: median AQI 59, with 9 days above AQI 100 out of 365 monitored — the 1st cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 140 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 307 days.
- ✓Cleanest month: September; worst: June.
Frequently asked questions
What was the average AQI in Detroit in 2021?▾
EPA's Air Quality System puts Detroit's (Detroit-Warren-Dearborn, MI) median daily AQI for 2021 at 59, which is Moderate. 9 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 140.
Which month had the worst air quality in Detroit in 2021?▾
The cleanest month of 2021 was September (median AQI 49, 0 days above 100) and the worst was June (median 60, 4 days above 100, peak 119).
Was 2021 a good or bad year for Detroit's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 1st cleanest by days above AQI 100 — the best year on record here. 2021's median of 59 is in line with the area's typical annual median of 58.
Detroit month by month in 2021
Detroit air quality month by month, 2021 (Detroit-Warren-Dearborn, MI, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 66 | 0 | 90 | PM2.5 |
| February | 28 | 66 | 1 | 119 | PM2.5 |
| March | 31 | 54 | 0 | 85 | PM2.5 |
| April | 30 | 55 | 0 | 94 | PM2.5 |
| May | 31 | 60 | 1 | 101 | PM2.5 |
| Juneworst | 30 | 60 | 4 | 119 | PM2.5 |
| July | 31 | 58 | 1 | 118 | PM2.5 |
| August | 31 | 62 | 2 | 140 | PM2.5 |
| Septembercleanest | 30 | 49 | 0 | 95 | PM2.5 |
| October | 31 | 58 | 0 | 84 | PM2.5 |
| November | 30 | 62 | 0 | 100 | PM2.5 |
| December | 31 | 63 | 0 | 90 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 1st cleanest by days above AQI 100 — the best year on record here.
2021's median of 59 is in line with the area's typical annual median of 58.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Detroit
The latest EPA AirNow observation puts Detroit's AQI at 56 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Detroit air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Detroit-Warren-Dearborn, 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.