Rochester Air Quality in May
Across 2019–2025, Rochester's May air quality had a median AQI of 39 (Good) over 217 monitored days in the Rochester, NY area. 0.9% of May days (2 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 77.0% of days. The cleanest May on record here was 2025 (median AQI 36, 0 days above 100) and the worst was 2023 (median 42, 2 days above 100, peak AQI 112).
- Good: 82.5%
- Moderate: 16.6%
- Unhealthy for Sensitive Groups: 0.9%
- Unhealthy or worse: 0.0%
Reducing Indoor Ozone
Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit also helps with the gases and VOCs that linger indoors.
Recommended: Coway AP-1512HH (HEPA + Carbon) — True HEPA + activated carbon layer · rooms up to 361 sq ft
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How is the air in Rochester in May?
Good on a typical day: median AQI 39 across 2019–2025, with 0.9% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓82.5% of May days were Good (AQI 0–50), 16.6% Moderate (51–100).
- ✓2 days of 217 reached AQI 101+; the May peak was 112.
- ✓Best May: 2025; worst May: 2023.
Frequently asked questions
What is the air quality like in Rochester in May?▾
Across 2019–2025, the median daily AQI in Rochester in May was 39 (Good). 82.5% of days were Good, 16.6% Moderate, and 0.9% 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 Rochester?▾
A typical May day in Rochester sits in the Good range (median AQI 39), 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 Rochester's May air quality problems?▾
Ground-level ozone set the daily AQI on 77.0% of May days in Rochester. The highest May AQI recorded in 2019–2025 was 112 (Unhealthy for Sensitive Groups), in 2023.
Rochester May air quality, year by year
Rochester May air quality by year (Rochester, NY, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 38 | 0 | 64 | O3 |
| 2020 | 31 | 38 | 0 | 54 | O3 |
| 2021 | 31 | 39 | 0 | 100 | O3 |
| 2022 | 31 | 42 | 0 | 64 | O3 |
| 2023worst | 31 | 42 | 2 | 112 | O3 |
| 2024 | 31 | 40 | 0 | 71 | O3 |
| 2025cleanest | 31 | 36 | 0 | 58 | O3 |
What May air means in Rochester
A typical May day in Rochester sits in the Good range (median AQI 39), 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 39 is in line with Rochester's whole-year median of 42, 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 Rochester runs below the national May norm; 0.9% of its May days topped AQI 100 versus 1.3% nationally (about the same).
May is part of Rochester's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Rochester, NY), 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.