Air Quality in Worcester, Massachusetts — Live
Live readings from PurpleAir sensors across Worcester — with free alerts the moment smoke drifts in.
AQI 29 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Worcester, Massachusetts is AQI 29 — Good and falling — with PM2.5 at 5.2 µg/m³, the median of 5 live PurpleAir sensors reading 26 to 33. 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 Worcester: 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 Worcester and Shrewsbury, Auburn, Holden, Millbury. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Worcester
The sensors Canairy reads in Worcester agree right now — all 5 sit in the Good band, a 7-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 0.4 mi ENE | 31 | Good |
| 0.6 mi WSW | 26 | Good |
| 0.9 mi NNW | 29 | Good |
| 2.1 mi W | 33 | Good |
| 4.7 mi ENE | 26 | Good |
Most days Worcester's air sits in the moderate range, with fine particle pollution the thing worth watching rather than any single smokestack. The memorable bad stretches have come from outside the city entirely: smoke carried down from Canadian wildfires, and summer ozone the whole Northeast inherits from upwind states.
What Canairy does for Worcester
A clear verdict
Not just a number — a plain-English call for Worcester: 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 Worcester or across the country, on one screen.
What the air in Worcester is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Good | ozone |
| Tomorrow | Good | ozone |
| Monday | Good | ozone |
| Tuesday | Good | ozone |
Forecast from EPA AirNow for the Worcester reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
The summer the smoke reached central Massachusetts
In June 2023, smoke from wildfires burning across Quebec drifted down over the Northeast in two distinct waves, the first around June 6 to 8 and a second at the end of the month. On June 6 New York City briefly had the worst air of any major city on earth, with an index reading above 400, and by June 7 the haze had settled across New England. At the peak roughly 128 million Americans were under air quality alerts at once.
For a lot of Worcester residents that was the first time the sky itself looked wrong, an orange cast over the hills and a smell that did not belong to anything nearby. The fires were hundreds of miles away, but the fine particles they threw up travel easily, and central Massachusetts sat right in the path. It was a plain reminder that your local air can turn unhealthy without a single local source, which is exactly the kind of change worth catching early.
A hill city where the air can settle in the low ground
Worcester is built on hills, famously seven of them, and sits about 479 feet up in the center of the state, roughly 40 miles west of Boston. The Blackstone River actually forms downtown, at the meeting of two smaller streams. That rolling terrain is part of the city's character, but it also means the air does not sit evenly everywhere. On calm, cold mornings colder air pools in the low neighborhoods and valleys while the hilltops clear, and whatever is in that trapped air, from traffic to winter wood smoke, tends to linger there until the wind picks up.
That is why one honest number for the whole city can hide real differences block to block. The reading on a breezy hilltop and the reading down in a still valley pocket on the same morning can tell you two different things. Checking the sensor closest to where you actually live, rather than a citywide average, is the difference that matters on those mornings.
The traffic you can see and the ozone you cannot
Worcester is a highway crossroads. I-290 cuts straight through the middle of the city, the Massachusetts Turnpike runs along the southern edge, and I-190, I-395, I-495 and Route 146 all feed into the area. That much traffic is a steady local source of the fine particles and nitrogen oxides that make up everyday tailpipe pollution, and it is felt most by the neighborhoods pressed up against those roads. Worcester is a working, densely settled city of around 207,000 people, and the households closest to the highways are often the ones already carrying more than their share.
The other half of the summer picture arrives on the wind. Massachusetts is part of the federal Ozone Transport Region, a multi-state group created precisely because ground-level ozone, the smog that builds on hot, sunny days, drifts across state lines from sources upwind. So a bad ozone afternoon in Worcester is often not really Worcester's doing, which is why the numbers can climb even when nothing local seems to have changed.
Worcester air quality FAQ
What is the air quality in Worcester right now?
As of September 5, 2026 at 8:10 AM EDT, the air quality in Worcester, Massachusetts is AQI 29 — Good — with PM2.5 at 5.2 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why did Worcester's air get so bad in June 2023?
Smoke from wildfires burning in Quebec drifted down over the Northeast in two waves that June, the first around June 6 to 8 and a second at the end of the month, and by June 7 the haze had reached New England. At the peak roughly 128 million Americans were under air quality alerts. The fires were hundreds of miles away, but the fine particles they produce travel easily, and central Massachusetts sat in the path.
Does Worcester get wildfire smoke even though there are no fires nearby?
Yes. Worcester's worst recent air came from Canadian wildfires hundreds of miles north in 2023, not from anything local. Fine particle pollution can ride the wind long distances, so the city's air can turn unhealthy with no local fire at all. That is exactly the kind of change worth being alerted to before you head outside.
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 Worcester, 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
Go deeper
Air quality near Worcester
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