Air Quality in Essex Junction, Vermont — Live
Live readings from PurpleAir sensors across Essex Junction — with free alerts the moment wildfire smoke or a winter inversion change what you're breathing.
AQI 0 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Essex Junction, Vermont is AQI 0 — Good and falling — with PM2.5 at 0.0 µg/m³, the median of 5 live PurpleAir sensors reading 0 to 0. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Essex Junction: weeds pollen is the strongest of the three at a moderate level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Essex Junction and Essex, Winooski, Williston, Colchester. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Essex Junction
The sensors Canairy reads in Essex Junction agree right now — all 5 sit in the Good band, a 0-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.9 mi NNW | 0 | Good |
| 3.3 mi NNE | 0 | Good |
| 3.4 mi W | 0 | Good |
| 4.3 mi E | 0 | Good |
| 6.3 mi SSW | 0 | Good |
Essex Junction's air is quiet most of the year — this stretch of the Champlain Valley is not a smog city, and Chittenden County rarely shows up on any list of the nation's polluted places. The exception is smoke. In June 2023, wildfire smoke drifting down from Quebec settled over the Winooski River valley twice in the same month, and the second wave pushed the Burlington monitor six miles away to an AQI of 224 — the worst air quality ever recorded in Vermont.
What Canairy does for Essex Junction
A clear verdict
Not just a number — a plain-English call for Essex Junction: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Essex Junction or across the country, on one screen.
Essex Junction lived through Vermont's worst air quality on record
The first wave came in the first week of June 2023, part of the same Quebec wildfire smoke plume that pushed New York City past an AQI of 400 and put roughly 128 million Americans under air quality alerts. Vermont got a milder dose that week, but it was only a preview. Three weeks later, over the weekend of June 24-26, smoke settled back in and this time it was worse: Burlington's monitor broke 200 AQI on Sunday the 25th, and by around 2 a.m. Monday it peaked at 224 with PM2.5 readings of 174 micrograms per cubic meter - a new state record for the worst air quality ever measured in Vermont. Photos from Browns Trace in Jericho, a few miles from Essex Junction, showed the same brown haze hanging over the road.
That same night, Montreal, less than 100 miles north, had the worst air quality of any city in the world. It was a reminder that the fires driving Vermont's air quality don't have to be in Vermont, or even in the same country - and that this wasn't a freak, one-time event. Vermont had already dealt with smoke from Manitoba's wildfires in 2021; in 2023 the source shifted to Quebec, but the underlying pattern is the same. Some summer, the wind is going to carry someone else's fire straight down the Champlain Valley again.
The valley traps its own smoke in winter
Essex Junction sits in the Champlain Valley, boxed in by the Green Mountains to the east and the Adirondacks across Lake Champlain to the west. On clear, calm winter nights that terrain lets cold, dense air pool at the valley floor while warmer air sits above it - a temperature inversion that acts like a lid, holding whatever is in the air close to the ground instead of letting it mix out. Winters here are genuinely cold, averaging around 19°F with lows that have hit -35°F, and cold nights mean wood stoves and pellet furnaces running hard across Chittenden County.
That combination - heavy winter heating and a valley that won't let the air move - is why Vermont's Department of Environmental Conservation publishes wood-smoke burning guidance every heating season, asking people to burn seasoned wood and avoid smoldering, low-temperature fires. It's a quieter problem than a wildfire-smoke event; the sky doesn't turn brown and there's no statewide alert. But fine particles from a neighborhood full of chimneys on a still, cold night can build up locally in a way one regional monitor won't fully capture, which is part of why Canairy leans on a network of sensors instead of a single number for the whole county.
What about the GlobalFoundries plant?
Essex Junction is also home to GlobalFoundries' Fab 9, a semiconductor manufacturing plant on River Street that dates back to IBM and is one of Chittenden County's largest employers. It operates under a Vermont Air Pollution Control Permit to Construct and Operate (AOP-12-022), which requires the state to sign off on its emissions controls before the plant can run. The environmental scrutiny the plant has drawn in recent years has mostly been about PFAS compounds turning up in wastewater discharged to the Winooski River - a water-quality issue, not an air one.
For day-to-day air quality, the plant is a permitted, monitored fixture rather than the thing driving the numbers up or down. The swings people actually notice in Essex Junction come from the two sources above: wildfire smoke rolling in some summers, and wood smoke settling into the valley on the coldest, stillest winter nights.
Essex Junction air quality FAQ
What is the air quality in Essex Junction right now?
As of September 14, 2026 at 8:09 AM EDT, the air quality in Essex Junction, Vermont is AQI 0 — Good — with PM2.5 at 0.0 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why did Essex Junction have such bad air in June 2023?
Wildfire smoke drifting down from Quebec settled over the Champlain Valley twice that month. The second event, over the weekend of June 24-26, pushed the Burlington monitor six miles away to an AQI of 224 with PM2.5 at 174 micrograms per cubic meter - the worst air quality ever recorded in Vermont. It wasn't a one-off; Vermont saw smoke from Manitoba's fires in 2021 too.
Does the GlobalFoundries plant affect Essex Junction's air quality?
The Fab 9 semiconductor plant operates under a Vermont air pollution permit (AOP-12-022) that requires state-approved emissions controls, and the environmental concerns it has drawn recently are about PFAS in wastewater, not ambient air quality. The bigger swings in Essex Junction's air come from wildfire smoke and winter wood smoke, not the plant.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Essex Junction, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Essex Junction
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