Dayton Air Quality in 2025
In 2025, Dayton's air quality (Dayton, OH area) had a median daily AQI of 47 (Good) across 365 monitored days. 4 days (1.1%) reached Unhealthy for Sensitive Groups or worse, 208 were Good, and the year's peak AQI was 129 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 204 of those days. The cleanest month of 2025 was January (median AQI 39, 0 days above 100) and the worst was September (median 57, 2 days above 100, peak 126).
- Good: 57.0%
- Moderate: 41.9%
- Unhealthy for Sensitive Groups: 1.1%
- Unhealthy or worse: 0.0%
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How was Dayton's air quality in 2025?
Good on a typical day: median AQI 47, with 4 days above AQI 100 out of 365 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 129 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 204 days.
- ✓Cleanest month: January; worst: September.
Frequently asked questions
What was the average AQI in Dayton in 2025?▾
EPA's Air Quality System puts Dayton's (Dayton, OH) median daily AQI for 2025 at 47, which is Good. 4 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 129.
Which month had the worst air quality in Dayton in 2025?▾
The cleanest month of 2025 was January (median AQI 39, 0 days above 100) and the worst was September (median 57, 2 days above 100, peak 126).
Was 2025 a good or bad year for Dayton's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 5th cleanest by days above AQI 100. 2025's median of 47 is below the area's typical annual median of 51.
Dayton month by month in 2025
Dayton air quality month by month, 2025 (Dayton, OH, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| Januarycleanest | 31 | 39 | 0 | 70 | PM2.5 |
| February | 28 | 50 | 0 | 67 | PM2.5 |
| March | 31 | 43 | 0 | 84 | O3 |
| April | 30 | 45 | 0 | 67 | O3 |
| May | 31 | 43 | 0 | 90 | O3 |
| June | 30 | 58 | 1 | 129 | PM2.5 |
| July | 31 | 56 | 1 | 129 | PM2.5 |
| August | 31 | 50 | 0 | 98 | PM2.5 |
| Septemberworst | 30 | 57 | 2 | 126 | O3 |
| October | 31 | 39 | 0 | 84 | O3 |
| November | 30 | 45 | 0 | 64 | PM2.5 |
| December | 31 | 53 | 0 | 77 | PM2.5 |
How 2025 compares
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 5th cleanest by days above AQI 100.
2025's median of 47 is below the area's typical annual median of 51.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Dayton
The latest EPA AirNow observation puts Dayton's AQI at 50 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Dayton air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Dayton, OH), 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.