Air Quality in Boston, Massachusetts — Live
Live readings from PurpleAir sensors across Boston — with free alerts the moment smoke drifts in.
AQI 37 from 5 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Boston, Massachusetts is AQI 37 — Good and holding steady — with PM2.5 at 6.7 µg/m³, the median of 5 live PurpleAir sensors reading 37 to 41. 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 Boston: weeds pollen is the strongest of the three at a low 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 Boston and Cambridge, Somerville, Brookline, Quincy. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Boston
The sensors Canairy reads in Boston agree right now — all 5 sit in the Good band, a 4-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 0.6 mi S | 41 | Good |
| 1.2 mi NNW | 37 | Good |
| 2.5 mi NE | 38 | Good |
| 3.6 mi NNE | 37 | Good |
| 4.6 mi W | 37 | Good |
For most of the year Boston's air is clean, cooled by ocean winds off Massachusetts Bay. But the picture has two edges. Summer now brings Canadian wildfire smoke almost every year, turning the sun into a dim orange ball and pushing the AQI into the unhealthy range for days at a time, and closer to home the pollution has always been about traffic and jet exhaust, concentrated along I-93 and the neighborhoods ringing Logan Airport.
What Canairy does for Boston
A clear verdict
Not just a number — a plain-English call for Boston: 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 Boston or across the country, on one screen.
What the air in Boston 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 Boston Metro 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.
Canadian wildfire smoke has become an almost annual summer event
In June 2023, smoke from fires in Quebec and Ontario drifted south and Boston's Air Quality Index climbed to 132, unhealthy for sensitive groups. The skyline turned orange, the air smelled acrid, and city officials told people to stay indoors. It happened again in July 2026, when the Massachusetts Department of Environmental Protection issued a statewide air quality alert, the AQI spiked to around 130, and the sun hung as a ghostly orange ball through a milky, campfire-scented haze.
What used to be a rare event is now a regular part of the New England summer. Air quality researchers point out that Boston saw occasional smoky days in the late 1990s and early 2000s, but that it has since become nearly an annual issue, and that per-person smoke exposure across the US was four times higher in 2020-2024 than in the years before. When smoke arrives, it is fine particle pollution (PM2.5) that does the damage, and it can settle over the whole region for days regardless of which neighborhood you live in.
Living near Logan means breathing what the planes leave behind
East Boston, Chelsea, and the harbor neighborhoods sit directly under Logan's flight paths, and researchers have spent years documenting what that means for the air. Aircraft taking off and landing throw off ultrafine particles, smaller than the width of a human hair and largely unregulated, and studies have traced plumes from Logan as far inland as Roxbury and Chelsea. Children living within about five miles of the airport have been found more likely to show respiratory symptoms consistent with undiagnosed asthma.
These particles do not show up cleanly in the standard AQI, which is built around PM2.5 and ozone, so a day can read as moderate downtown while the air just downwind of a runway is considerably worse. If you live in one of these neighborhoods, the reading from the sensor closest to you matters far more than a citywide average, and wind direction off the harbor can change your exposure hour to hour.
The I-93 corridor and the near-highway research it produced
Boston has a rare thing: a long-running academic study of what it means to live next to a highway. The Tufts-led CAFEH project (Community Assessment of Freeway Exposure and Health) followed roughly 700 residents in Somerville and Chinatown living close to I-93. It found ultrafine-particle counts around 100,000 particles per cubic centimeter in the neighborhoods nearest the highway during the early morning rush, and linked that exposure to elevated blood pressure and inflammatory markers in the people who lived there.
That pollution is worst between about 6 and 8 in the morning, when traffic is heavy and the air is still. It falls off sharply within a few hundred meters of the road, which is why two homes on the same street can have meaningfully different air. Traffic is also part of why the Boston-Worcester-Providence metro area earned failing grades for both ozone smog and daily particle pollution in the American Lung Association's 2026 State of the Air report, even as its year-round particle levels reached a best-ever passing grade.
Boston air quality FAQ
What is the air quality in Boston right now?
As of September 5, 2026 at 8:10 AM EDT, the air quality in Boston, Massachusetts is AQI 37 — Good — with PM2.5 at 6.7 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Does wildfire smoke really reach Boston?
Yes, and it now does so most summers. Smoke from fires in Quebec and Ontario drifted over the city in June 2023, pushing the AQI to 132, and again in July 2026 when a statewide air quality alert went out and the AQI spiked to around 130. On those days the whole region breathes elevated fine particle pollution, so the sensor closest to you is the best guide to when to close the windows or move a workout indoors.
Is the air worse near Logan Airport and I-93?
Local research says yes. Studies have tracked ultrafine particles from Logan's aircraft across East Boston, Chelsea, and as far as Roxbury, and the Tufts CAFEH study measured very high particle counts along I-93 in Somerville and Chinatown, worst during the early-morning rush. These ultrafine particles are not fully captured by the standard AQI, so if you live near the airport or the highway, watch the nearest sensor rather than a citywide number.
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 Boston, 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 Boston
We watch Boston's air. You live your life.
Set your threshold once and get a heads-up only when the air actually changes for you. Free on the App Store & Google Play.