Burlington Air Quality in September
Across 2019–2025, Burlington's September air quality had a median AQI of 33 (Good) over 210 monitored days in the Burlington-South Burlington, VT area. 0.0% of September days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 57.1% of days. The cleanest September on record here was 2020 (median AQI 31, 0 days above 100) and the worst was 2023 (median 39, 0 days above 100, peak AQI 82).
- Good: 89.0%
- Moderate: 11.0%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Burlington in September?
Good on a typical day: median AQI 33 across 2019–2025, with 0.0% of September days above AQI 100. Ground-level ozone is the main driver.
- ✓89.0% of September days were Good (AQI 0–50), 11.0% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the September peak was 82.
- ✓Best September: 2020; worst September: 2023.
Frequently asked questions
What is the air quality like in Burlington in September?▾
Across 2019–2025, the median daily AQI in Burlington in September was 33 (Good). 89.0% of days were Good, 11.0% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is September a good time for outdoor exercise in Burlington?▾
A typical September day in Burlington sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
Which pollutant causes Burlington's September air quality problems?▾
Ground-level ozone set the daily AQI on 57.1% of September days in Burlington. The highest September AQI recorded in 2019–2025 was 82 (Moderate), in 2023.
Burlington September air quality, year by year
Burlington September air quality by year (Burlington-South Burlington, VT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 32 | 0 | 59 | PM2.5 |
| 2020cleanest | 30 | 31 | 0 | 61 | O3 |
| 2021 | 30 | 32 | 0 | 49 | O3 |
| 2022 | 30 | 34 | 0 | 52 | PM2.5 |
| 2023worst | 30 | 39 | 0 | 82 | PM2.5 |
| 2024 | 30 | 37 | 0 | 52 | O3 |
| 2025 | 30 | 31 | 0 | 58 | O3 |
What September air means in Burlington
A typical September day in Burlington sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
September's median AQI of 33 is below Burlington's whole-year median of 39, making it one of the area's cleaner periods. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so Burlington runs below the national September norm; 0.0% of its September days topped AQI 100 versus 2.7% nationally (below average).
September is part of Burlington's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Burlington
The latest EPA AirNow observation puts Burlington's AQI at 27 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Burlington air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Burlington-South Burlington, VT), 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.