Air Quality in New Haven, Connecticut — Live
Live readings from PurpleAir sensors across New Haven — with free alerts the moment the ozone climbs.
AQI 16 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in New Haven, Connecticut is AQI 16 — Good and falling — with PM2.5 at 2.9 µg/m³, the median of 5 live PurpleAir sensors reading 16 to 27. 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 New Haven: 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 New Haven and Hamden, West Haven, East Haven, North Haven. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in New Haven
The sensors Canairy reads in New Haven agree right now — all 5 sit in the Good band, a 11-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.2 mi SSW | 16 | Good |
| 1.4 mi WNW | 24 | Good |
| 1.8 mi SE | 27 | Good |
| 2.5 mi ENE | 17 | Good |
| 3.4 mi SSE | 16 | Good |
New Haven's air is unremarkable most of the year — this is a harbor city on Long Island Sound, not a valley or a basin, and there's no refinery or steel mill upwind driving daily pollution. The exception is summer. On hot, sunny afternoons, exhaust from the New York City area rides a southwest wind out over Long Island Sound, gets trapped low over the Sound's cool water, and then rides the afternoon sea breeze straight back onto the Connecticut shoreline as ground-level ozone. It's a pattern researchers have measured directly at monitoring sites in New Haven itself, and it's serious enough that in 2024 federal regulators reclassified New Haven County's ozone problem as more severe, not less.
What Canairy does for New Haven
A clear verdict
Not just a number — a plain-English call for New Haven: open the windows, or keep them shut.
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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
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New Haven's summer ozone is mostly someone else's exhaust
The Long Island Sound Tropospheric Ozone Study (LISTOS), a NASA- and EPA-backed research campaign, ran ground stations in New Haven alongside Westport, Hammonasset State Park, and Outer Island through the summer of 2018. What it confirmed is a mechanism specific to this coastline: the Sound's cool water holds the New York City area's ozone-forming exhaust in a shallow, stable layer just offshore, and as the land heats up in the afternoon, the resulting sea breeze pushes that same plume straight onto the Connecticut shore — New Haven included.
That transported pollution is why New Haven County, along with Fairfield and Middlesex counties, is part of the New York-Northern New Jersey-Long Island ozone nonattainment area. In July 2024 the EPA agreed to a request from New York, New Jersey, and Connecticut to reclassify that whole region from Moderate to Serious for the federal ozone standard — an acknowledgment that despite the region's own cleanup efforts, the summer ozone problem here isn't going away on its own. The American Lung Association's 2025 State of the Air report gave the New Haven-Hartford-Waterbury metro area an F for ozone, ranking it 38th worst in the country.
Tweed Airport adds a newer, more local worry
In June and July 2023, Tufts University researcher Neelakshi Hudda set up twelve monitors around Tweed New Haven Airport and drove instrumented routes through the surrounding streets. She found that unregulated ultrafine particles — the kind thrown off by burning jet fuel — spiked measurably, both outdoors and inside nearby homes, whenever planes took off or landed, with the effect strongest within about half a mile of the runway and shifting with the wind.
The findings landed in the middle of a live local fight over the airport's plans for a new terminal and a longer runway, and Tweed has since offered a Residential Indoor Air Program supplying air purifiers to eligible households nearby. Separately, the city of New Haven has installed its own network of air-quality sensors around town — a sign that, airport politics aside, people here want a real, local answer to what they're breathing, not just a regional forecast.
The one summer the sky actually turned orange
New Haven doesn't have a wildfire season of its own, but it got a preview of one in June 2023, when smoke from fires burning in Quebec, Ontario, and Nova Scotia drifted south into New England. On June 7 the sky over the Connecticut shoreline turned a deep orange-brown, schools canceled outdoor activities, and air quality alerts covering New Haven and the rest of the state warned residents to stay inside with the windows shut as readings reached Unhealthy and Very Unhealthy levels. A second, milder round of Canadian smoke returned at the end of the month.
It was a genuine outlier, not a preview of a new normal — nothing like it has repeated since, and it isn't the kind of thing New Haven needs to plan a season around the way a California or Pacific Northwest city does. But it's a reminder that even a city whose air problems are normally slow and seasonal can get a fast, ugly surprise from a source thousands of miles away, which is exactly the kind of change worth a sensor check rather than a guess from the color of the sky.
New Haven air quality FAQ
What is the air quality in New Haven right now?
As of September 14, 2026 at 8:10 AM EDT, the air quality in New Haven, Connecticut is AQI 16 — Good — with PM2.5 at 2.9 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does New Haven's air get worse in summer?
Summer heat and sun cook up ground-level ozone, and New Haven sits directly downwind of the New York City area across Long Island Sound. On hot, sunny afternoons a sea breeze carries that transported exhaust back onto the Connecticut shoreline, which is why New Haven County's ozone problem was reclassified from Moderate to Serious by the EPA in 2024.
Does Tweed Airport affect New Haven's air quality?
A 2023 Tufts University study found that ultrafine particles from jet exhaust spike noticeably near Tweed New Haven Airport during takeoffs and landings, especially within about half a mile of the runway. It's a smaller, more localized issue than the region's summer ozone, but it's a real one, and it's part of why the airport now offers an indoor air purifier program to some nearby households.
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 New Haven, 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 New Haven
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