Dayton Air Quality in May
Across 2019–2025, Dayton's May air quality had a median AQI of 48 (Good) over 217 monitored days in the Dayton, OH area. 0.0% of May days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 65.0% of days. The cleanest May on record here was 2025 (median AQI 43, 0 days above 100) and the worst was 2023 (median 54, 0 days above 100, peak AQI 100).
- Good: 55.3%
- Moderate: 44.7%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Improve Indoor Air Quality
Even with good outdoor air in Dayton, 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 Dayton in May?
Good on a typical day: median AQI 48 across 2019–2025, with 0.0% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓55.3% of May days were Good (AQI 0–50), 44.7% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the May peak was 100.
- ✓Best May: 2025; worst May: 2023.
Frequently asked questions
What is the air quality like in Dayton in May?▾
Across 2019–2025, the median daily AQI in Dayton in May was 48 (Good). 55.3% of days were Good, 44.7% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is May a good time for outdoor exercise in Dayton?▾
A typical May day in Dayton sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
Which pollutant causes Dayton's May air quality problems?▾
Ground-level ozone set the daily AQI on 65.0% of May days in Dayton. The highest May AQI recorded in 2019–2025 was 100 (Moderate), in 2023.
Dayton May air quality, year by year
Dayton May air quality by year (Dayton, OH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 54 | 0 | 74 | O3 |
| 2020 | 31 | 45 | 0 | 64 | O3 |
| 2021 | 31 | 52 | 0 | 78 | O3 |
| 2022 | 31 | 48 | 0 | 74 | O3 |
| 2023worst | 31 | 54 | 0 | 100 | O3 |
| 2024 | 31 | 52 | 0 | 87 | O3 |
| 2025cleanest | 31 | 43 | 0 | 90 | O3 |
What May air means in Dayton
A typical May day in Dayton sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
May's median AQI of 48 is in line with Dayton's whole-year median of 51, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Dayton runs above the national May norm; 0.0% of its May days topped AQI 100 versus 1.3% nationally (below average).
May is part of Dayton's spring season (March, April, May); the spring page pools all three months.
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 month 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.