Rochester Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Rochester (Rochester, NY area) was June 30, 2023, when the daily AQI reached 176 (Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 5 of the 10 worst days were Unhealthy (AQI 151+) or worse; 9 of the 10 were driven by fine particulate matter (PM2.5) and 1 by ground-level ozone, and 6 of them fell in 2023. The cleanest day was October 29, 2023 at AQI 15 (Good); the 10 best days span 5 different years.
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When were Rochester's worst and best air quality days?
Worst: June 30, 2023, AQI 176 (Unhealthy, PM2.5). Best: October 29, 2023, AQI 15 (Good). Based on 2,557 EPA-monitored days in the Rochester, NY area, 2019–2025.
- ✓5 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 119 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) drove 9 of the 10 worst days.
- ✓2023 accounts for 6 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Rochester?▾
June 30, 2023: the Rochester, NY area's daily AQI hit 176 (Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Rochester?▾
October 29, 2023, with a daily AQI of 15 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Rochester's worst air quality day in 2025?▾
June 7, 2025, AQI 135 (Unhealthy for Sensitive Groups), set by fine particulate matter (PM2.5), in wildfire smoke season.
Which pollutant causes Rochester's worst air days?▾
Fine particulate matter (PM2.5) set the AQI on 9 of the 10 worst days; ground-level ozone on 1. The tables above list the defining pollutant for every day.
Rochester's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Rochester, NY area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 176 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 173 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2023 page) | 171 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 4 | (2023 page) | 167 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 5 | (2023 page) | 151 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2023 page) | 136 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 7 | (2025 page) | 135 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2025 page) | 133 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 9 | (2022 page) | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 10 | (2025 page) | 119 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Worst day of each year in Rochester
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 90 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2020 | 81 | Moderate | PM2.5 — fine particulate matter (PM2.5) | |
| 2021 | 100 | Moderate | O3 — ground-level ozone | |
| 2022 | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2023 | 176 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 90 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2025 | 135 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Rochester's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Rochester, NY area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 15 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2021 page) | 15 | Good | O3 — ground-level ozone |
| 3 | (2025 page) | 16 | Good | O3 — ground-level ozone |
| 4 | (2023 page) | 16 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2021 page) | 16 | Good | O3 — ground-level ozone |
| 6 | (2019 page) | 17 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2025 page) | 18 | Good | O3 — ground-level ozone |
| 8 | (2025 page) | 18 | Good | O3 — ground-level ozone |
| 9 | (2024 page) | 18 | Good | O3 — ground-level ozone |
| 10 | (2025 page) | 19 | Good | PM2.5 — fine particulate matter (PM2.5) |
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.