Air Quality in Rochester, New Hampshire — Live
Live readings from PurpleAir sensors across Rochester — with free alerts the moment the air actually changes.
AQI 16 from 2 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Rochester, New Hampshire is AQI 16 — Good and falling — with PM2.5 at 2.9 µg/m³, the median of 2 live PurpleAir sensors reading 1 to 31. 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 Rochester: 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 Rochester and Dover, Somersworth, Farmington, Barrington. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Rochester
The sensors Canairy reads in Rochester agree right now — all 2 sit in the Good band, a 30-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 6.2 mi S | 1 | Good |
| 9.9 mi SE | 31 | Good |
Rochester's air is good most of the year — this is coastal New Hampshire, not a smog basin, and there's no mountain ring here to trap anything in place. What actually shows up in Rochester's air comes from three specific, unrelated sources: the Turnkey Landfill on the city's east side, which has drawn years of resident odor complaints; hot, hazy summer afternoons when ozone drifts up the Northeast corridor from Boston and beyond; and, in June 2023, smoke from Canadian wildfires that pushed particle pollution to unhealthy levels statewide for a couple of days.
What Canairy does for Rochester
A clear verdict
Not just a number — a plain-English call for Rochester: 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 Rochester or across the country, on one screen.
Rochester's air problem has a street address
Most cities' air-quality stories are about weather and geography. Rochester's is also about a specific 1,300-acre property at 176 Rochester Neck Road: the Turnkey Landfill, one of the largest waste facilities in New England, taking in more than a million tons of trash a year from across the Seacoast region and beyond. Landfill gas from the site is collected and burned in flares and gas-to-electric plants — enough to power roughly 7,000 homes and to supply fuel to UNH's Durham campus — but the process isn't airtight.
Starting in 2023, Rochester residents reported the odor getting noticeably worse, and Waste Management's director of disposal operations, Steve Poggi, told the city council that October the company had taken 'immediate and aggressive action to correct the causes.' Five residents petitioned the EPA in February 2024 to block the site's Title V air permit; the agency denied that petition in August 2024, and the state approved a 60-acre expansion of the landfill in October 2023 regardless. The smell isn't the same thing as the particle count on a sensor, but it's the reason a lot of people in Rochester check the air before they decide whether to open a window.
Summer haze usually isn't made here — it arrives here
On hot, humid, windless days, New Hampshire's Department of Environmental Services sometimes issues a statewide Air Quality Action Day for ground-level ozone. The state's own description is blunt about where it comes from: the pollution is 'the result of winds transporting pollutant emissions into New Hampshire from surrounding areas, which combine with local emissions' — meaning car and power-plant exhaust from Boston, New York, and everywhere in between, cooked into ozone by sunlight as it drifts north up the I-95 corridor.
New Hampshire has actually been trying to get out from under this problem at the policy level: it's part of the Ozone Transport Commission, the regional compact set up under the 1990 Clean Air Act to manage exactly this kind of imported smog, and the state has moved to withdraw from it, arguing decades of vehicle and power-plant cleanup have made the old regional framework less necessary. Action days are rarer than they used to be, but a still, 90-degree July afternoon in Rochester can still push ozone into Moderate or worse.
June 2023 was the exception that proved the rule
For most of Rochester's history, wildfire smoke was something that happened to other regions. That changed in late June 2023, when smoke from wildfires burning across Quebec and northern Ontario rode south on the jet stream and settled over New England. NHDES issued an advisory warning that fine particle pollution would reach levels unhealthy for sensitive groups on June 29 and 30, and the haze was thick enough to see and smell from Rochester to the Seacoast.
It was a one-off by New Hampshire standards, not an annual season the way it is in the Mountain West — but it showed that a fire a thousand miles away can still matter here. Canairy's sensor network is what catches that kind of day early, rather than relying on the sky looking obviously orange before anyone checks a number.
Rochester air quality FAQ
What is the air quality in Rochester right now?
As of September 14, 2026 at 8:10 AM EDT, the air quality in Rochester, New Hampshire is AQI 16 — Good — with PM2.5 at 2.9 µg/m³, the median of 2 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Rochester sometimes smell bad even when the AQI looks fine?
That's usually the Turnkey Landfill on Rochester Neck Road, one of the largest waste facilities in New England, which has drawn years of resident odor complaints and a 2024 EPA petition over its air permit. Odor and measured particle pollution aren't the same thing - you can smell a landfill on a still day without the PM2.5 reading changing much - but it's the most common local reason people in Rochester check the air before opening windows.
Does wildfire smoke ever reach Rochester, NH?
It's rare, but it happened in late June 2023, when smoke from wildfires burning across Quebec and northern Ontario drifted down into New England. New Hampshire's Department of Environmental Services issued an advisory for fine particle pollution reaching levels unhealthy for sensitive groups on June 29 and 30. Unlike the West Coast, this isn't an annual season here, but a big enough Canadian fire year can still send smoke this far south.
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 2 curated PurpleAir sensors Canairy tracks in and around Rochester, 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 Rochester
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