Rochester, Wisconsin Air Quality
Rochester air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Rochester, WI · Air quality right now
The air quality index in Rochester, WI is 27 (Good) right now — safe for outdoor activity.
Is it safe to be outside in Rochester today?
AQI 27 Yes — air quality is Good
Air is clean — great for outdoor activity.Main pollutant: PM2.5Observed 10:00 AM CDT
Pollutants right now
- PM2.57.1 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM107.3 µg/m³coarse particles — dust, pollen, ash
- Ozone55 µg/m³smog — builds on hot, sunny days
- NO₂2.6 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run — no air-quality limits on outdoor exercise.
How to read Rochester’s air quality
Guides: The AQI Scale, Explained · Air Quality Alerts, Decoded · How to Read a Wildfire Smoke Map · Why Wildfire Smoke Travels 1,000 Miles.
Air quality over time in Rochester
Across the EPA’s county records from 2020 to 2025, Rochester’s cleanest year was 2020 (median AQI 38) and its most polluted was 2023 (median AQI 44); the typical (median) day has trended more polluted since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 38 | 1 | Ozone | 7 | 29 | 162 |
| 2021 | 43 | 0 | Ozone | 8 | 53 | 149 |
| 2022 | 40 | 1 | Ozone | 2 | 34 | 165 |
| 2023 | 44 | 2 | Ozone | 14 | 49 | 138 |
| 2024 | 42 | 1 | Ozone | 10 | 38 | 156 |
| 2025 | 41 | 0 | Ozone | 8 | 40 | 151 |
“USG” is Unhealthy for Sensitive Groups (AQI 101–150); “Unhealthy+” combines the Unhealthy, Very Unhealthy, and Hazardous days. In 2024 the EPA tightened the annual fine-particle (PM2.5) standard to 9 µg/m³ from the previous 12 µg/m³, so counties near the old limit read worse against the new one. Source: EPA AQS annual summaries, 2020–2025.
Frequently asked
- What was the worst year for air quality in Rochester?
- In the EPA's 2020–2025 county records, 2023 had the most days above AQI 100: 16 days (14 Unhealthy for Sensitive Groups, 2 Unhealthy or worse). It also had the highest median AQI, 44.
- How many unhealthy air days does Rochester have?
- Across 2020–2025, 4% of the days reported for Rochester's county had an AQI above 100 (54 of 1218), about 9 days a year. 2025 had 8 days.
- What's the main air pollutant in Rochester?
- Ozone: it drove Rochester's county AQI on the most days in every year of the EPA's 2020–2025 records.