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.

Live Essex Junction AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Essex Junction and Essex, Winooski, Williston, Colchester.

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.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

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?

This page shows the current AQI for Essex Junction, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood.

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 AQI level is unhealthy?

Under the US EPA scale, AQI 0-50 is Good and 51-100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups - kids, older adults, and people with asthma or heart conditions - and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Where does Canairy's Essex Junction data come from?

Readings come from PurpleAir's network of laser particle sensors across Essex Junction and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.