Is the Air Quality Good in Chittenden, Vermont?
Mostly — air quality in Chittenden, Vermont is fair, not pristine. The city earns a Grade of C (fair) on a 5-year median AQI of 40 (Good), with 7 unhealthy-air days over five years (about 1 per year). Healthy adults are fine most of the time, but sensitive groups should watch the daily forecast.
Who Can Safely Breathe the Air in Chittenden, Vermont?
Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
Across the past five years, this area has logged just 7 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 1 days per year, or roughly one every other month. That is a low count by national standards.
Chittenden, Vermont Air Quality Snapshot
| Air Quality Grade | C63/100 |
| 5-Year Median AQI | 40 (Good) |
| Most Recent Median AQI (2023) | 42 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Stable (+0.29 AQI/yr) |
| Unhealthy Days (last 5 yr) | 7 |
| National Rank (cleanest = #1) | #499 of 1,020 (49th cleanest percentile) |
| Vermont Rank | #4 of 4 |
What Does the C Grade Mean?
Chittenden, Vermont earns a C — air quality is fair, but not great. With a 5-year median AQI of 40, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.
Chittenden, Vermont's 5-year median AQI of 40 is right around the national average of 41 across the 1,020 monitored U.S. cities tracked here. Within Vermont, Chittenden, Vermont runs more polluted than the state average of 32 — local sources or geography are concentrating pollution above the state's typical reading.
For context within Vermont: Windham, Vermont currently holds the state's cleanest grade (A, AQI 12), while Rutland, Vermont sits at the bottom (B, AQI 39).
What's in Chittenden, Vermont's Air?
The dominant pollutant in Chittenden, Vermont is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 192 | 53% |
| Fine Particulate Matter (PM2.5) | 171 | 47% |
| Carbon Monoxide | 2 | 1% |
Is the Air Getting Better or Worse?
Air quality in Chittenden, Vermont has held roughly steady over the past decade, with year-to-year shifts in median AQI of less than half a point. That stability makes the city's long-run grade a reliable signal of what residents can expect day-to-day.
In 2014, Chittenden, Vermont posted a median AQI of 41. By 2023 that figure was 42 — a rise of 1 AQI points dirtier across 10 years of EPA records.
Year-by-Year AQI in Chittenden, Vermont
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 41 | 288 | 0 | Ozone |
| 2015 | 39 | 278 | 0 | Ozone |
| 2016 | 36 | 319 | 0 | Ozone |
| 2017 | 37 | 312 | 0 | Ozone |
| 2018 | 40 | 295 | 0 | Ozone |
| 2019 | 39 | 306 | 0 | Ozone |
| 2020 | 39 | 302 | 0 | Ozone |
| 2021 | 40 | 288 | 1 | PM2.5 |
| 2022 | 41 | 298 | 0 | Ozone |
| 2023 | 42 | 259 | 6 | Ozone |
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Chittenden, Vermont
Chittenden, Vermont has an Air Quality Grade of C (fair) with a 5-year median AQI of 40. The dominant pollutant is Ground-Level Ozone, and air quality has been stable over the past decade.
This answer pulls from the EPA Air Quality System (AQS), the authoritative federal source for U.S. air quality and pollution monitoring. The headline number above is the direct answer; what follows is the additional context most readers need to use the answer for a real decision rather than just a fact lookup.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.