SO2 in Rochester, NY
Sulfur Dioxide in the Rochester, NY area: 2019–2025 measured EPA records, health thresholds and what the numbers mean.
No live SO2 reading for Rochester right now
EPA AirNow was not reporting a monitored observation for Rochester, New York when this page was last updated, so there is no current SO2 number to show. We do not estimate or model one. The measured history below comes from EPA's Air Quality System and does not depend on today's feed.
Last checked: September 26, 2026 at 5:07 PM UTC.
Check Rochester on AirNow.govRochester Air Quality Record, 2019–2025
EPA publishes one daily AQI value per metropolitan area — the highest value any regulatory monitor in the area reported that day. For Rochester that area is Rochester, NY. In 2025 monitors there reported air quality on 365 days, with a median AQI of 39, a 90th-percentile AQI of 61 and a worst day of 135. 7 of those days reached AQI 101 or higher (Unhealthy for Sensitive Groups or worse).
Across 2019–2025, Rochester's air worsened: the area's median AQI held near 42 and days above AQI 100 rose from about 0 to 6 per year (comparing the earlier and later halves of the period).
| Year | Days measured | Median AQI | 90th pct AQI | Worst day | Days AQI 101+ |
|---|---|---|---|---|---|
| 2019 | 365 | 42 | 58 | 90 | 0 |
| 2020 | 366 | 41 | 58 | 81 | 0 |
| 2021 | 365 | 44 | 61 | 100 | 0 |
| 2022 | 365 | 42 | 58 | 126 | 2 |
| 2023 | 365 | 43 | 64 | 176 | 11 |
| 2024 | 366 | 39 | 57 | 90 | 0 |
| 2025 | 365 | 39 | 61 | 135 | 7 |
Source: EPA Air Quality System (AQS) pre-generated Annual AQI by CBSA files, https://aqs.epa.gov/aqsweb/airdata/download_files.html (retrieved 2026-09-07). Area: Rochester, NY (Core Based Statistical Area 40380).
How often is SO2 the main pollutant in Rochester?
EPA's annual AQI summary files break out the number of days led by ozone, PM2.5, PM10, NO2 and CO, but not by sulfur dioxide. Sulfur dioxide rarely sets the daily AQI in US metropolitan areas, so no SO2-specific day count is published for Rochester, NY. The area-wide table above still describes the air Rochester residents breathed, and the thresholds below are the EPA breakpoints that would apply if SO2 did lead.
About Sulfur Dioxide
A gas from burning fossil fuels, can affect breathing.
Measured in ppb.
What is a safe level of SO2?
By the EPA Air Quality Index, sulfur dioxide is Good — safe for everyone up to 35 ppb (AQI 50). Between that and 75 ppb (AQI 100) the air is Moderate: fine for most people, but unusually sensitive individuals may notice symptoms. Above 75 ppb the AQI enters Unhealthy for Sensitive Groups and EPA health guidance begins.
What each AQI level means for SO2
- 0–50 GoodAir quality is considered satisfactory, and air pollution poses little or no risk.
- 51–100 ModerateAir quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
- 101–150 Unhealthy for Sensitive GroupsMembers of sensitive groups may experience health effects. The general public is not likely to be affected.
- 151–200 UnhealthyEveryone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
- 201–300 Very UnhealthyHealth warnings of emergency conditions. The entire population is more likely to be affected.
- 301–500 HazardousHealth alert: everyone may experience more serious health effects.
More Rochester air quality data
Rochester Air Quality by Month
Median daily AQI for each calendar month, pooled across 2019–2025 for the Rochester, NY area (EPA Air Quality System). Colour is the EPA category of that median. Open a month for its day counts, worst years and main pollutant.
By season
By year
Rochester’s best and worst air quality days on record (2019–2025) →
Each figure is the median of every monitored day in that period, 2019–2025; a year’s median is EPA’s published annual figure. Source: EPA AQS Daily AQI by CBSA, retrieved 2026-09-09.