Dayton Air Quality in Fall
Across 2019–2025, Dayton's fall (September–November) air quality had a median AQI of 47 (Good) over 637 monitored days in the Dayton, OH area. 0.3% of fall days (2 of 637) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 67.5% of days. The cleanest fall on record here was 2024 (median AQI 43, 0 days above 100) and the worst was 2025 (median 47, 2 days above 100, peak AQI 126).
- Good: 57.3%
- Moderate: 42.4%
- Unhealthy for Sensitive Groups: 0.3%
- Unhealthy or worse: 0.0%
Improve Indoor Air Quality
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How is the air in Dayton in fall?
Good on a typical day: median AQI 47 across 2019–2025, with 0.3% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓57.3% of fall days were Good (AQI 0–50), 42.4% Moderate (51–100).
- ✓2 days of 637 reached AQI 101+; the fall peak was 126.
- ✓Cleanest month: October; worst month: September.
Frequently asked questions
What is the air quality like in Dayton in fall?▾
Across 2019–2025, the median daily AQI in Dayton in fall was 47 (Good). 57.3% of days were Good, 42.4% Moderate, and 0.3% reached Unhealthy for Sensitive Groups or worse, based on 637 monitored days in EPA's Air Quality System.
Is fall a good time for outdoor exercise in Dayton?▾
A typical fall day in Dayton sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Which pollutant causes Dayton's fall air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 67.5% of fall days in Dayton. The highest fall AQI recorded in 2019–2025 was 126 (Unhealthy for Sensitive Groups), in 2025.
Dayton fall air quality, year by year
Dayton fall air quality by year (Dayton, OH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 91 | 53 | 0 | 87 | PM2.5 |
| 2020 | 91 | 49 | 0 | 96 | PM2.5 |
| 2021 | 91 | 48 | 0 | 97 | PM2.5 |
| 2022 | 91 | 44 | 0 | 76 | PM2.5 |
| 2023 | 91 | 46 | 0 | 70 | PM2.5 |
| 2024cleanest | 91 | 43 | 0 | 90 | PM2.5 |
| 2025worst | 91 | 47 | 2 | 126 | O3 |
What fall air means in Dayton
A typical fall day in Dayton sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Fall's median AQI of 47 is below Dayton's whole-year median of 51, making it one of the area's cleaner periods. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Dayton runs above the national Fall norm; 0.3% of its Fall days topped AQI 100 versus 1.5% nationally (below average).
Within the season, October is the cleanest month (median AQI 44, 0.0% of days above 100) and September the worst (median 49, 1.0% above 100).
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 season 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.