Air Quality in Concord, New Hampshire — Live
Live readings from PurpleAir sensors across Concord — with free alerts when summer ozone or wildfire smoke push the air past healthy.
AQI 29 from 3 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Concord, New Hampshire is AQI 29 — Good and falling — with PM2.5 at 5.2 µg/m³, the median of 3 live PurpleAir sensors reading 28 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 Concord: 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 Concord and Bow, Hopkinton, Pembroke, Loudon. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Concord
The sensors Canairy reads in Concord agree right now — all 3 sit in the Good band, a 3-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 2.0 mi SW | 31 | Good |
| 6.5 mi SE | 29 | Good |
| 8.3 mi SSE | 28 | Good |
Concord's air is good on most days of the year — this is a small state capital in the Merrimack River valley, not a place known for pollution. The two things that actually move the needle are summer ground-level ozone, driven by heat and regional traffic along the I-93 corridor, and — a newer pattern — smoke drifting down from Canadian wildfires that has triggered a growing share of New Hampshire's air quality alerts since 2023.
What Canairy does for Concord
A clear verdict
Not just a number — a plain-English call for Concord: 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 Concord or across the country, on one screen.
Why Concord gets ozone alerts on hot days
New Hampshire has belonged to the Ozone Transport Region since the Commission was created under the Clean Air Act in 1991 — a corridor of 13 states plus Washington, D.C. stretching from Virginia to Maine, set up because ground-level ozone drifts across state lines faster than any one state can regulate it. Concord sits inside that corridor, threaded by I-93 and I-89, so on a hot, still afternoon the exhaust and industrial emissions pushed north from Boston and the rest of southern New England mix with local traffic and push the numbers into unhealthy territory for people with asthma or heart conditions.
That's what happened in late May 2024, when an early-season heat wave pushed New Hampshire's Department of Environmental Services to issue back-to-back ozone advisories. "Maybe hold off on going for your afternoon run or any outdoor exercise in general," the department's Air Quality Analysis Supervisor, Marcus Chase, told New Hampshire Public Radio. Dr. Paul Friedrichs, of New Hampshire Health Care Workers for Climate Action, explained the mechanism at the time: heat and combustion — cars, power plants — drive ground-level ozone higher, compounding whatever fine-particle pollution is already in the air.
Canadian wildfire smoke is becoming a summer regular
For most of Concord's history, wildfire smoke was someone else's problem. That's changed. In summer 2025, six of the eight air quality alerts New Hampshire DES issued statewide were triggered by smoke drifting down from Canadian wildfires rather than local pollution. "Something that used to not be part of our routine is now routine," state air quality scientist Kathleen Simmons told New Hampshire Public Radio in August 2025.
It isn't a one-off year. Canadian wildfire smoke forced DES to declare air quality action days over the weekend of June 30 to July 2, 2023, hitting the western half of the state and anywhere above 2,000 feet elevation hardest, and lingering smoke was still triggering advisories in Grafton, Sullivan, and Cheshire counties as recently as August 2025. Those alerts are issued statewide, so Concord sits under the same advisory even on days when the reporting focuses on the hillier counties to its west.
Why one number for Concord isn't the whole story
Concord straddles the Merrimack River, with downtown sitting on a low terrace west of the water and the Soucook River marking the city's eastern edge. Step outside the urban core and the city is ringed by small, heavily wooded towns — Bow, Hopkinton, Pembroke, Canterbury, Loudon — that look and behave nothing like the blocks around the State House a few miles away.
A single ozone or smoke reading reported for Concord or Merrimack County can miss that difference entirely. Canairy reads the actual PurpleAir sensors near the places you've saved instead of one faraway monitor, so a reading near downtown can look different from one out past Penacook or toward the Bow town line — useful on the handful of days a year when the difference actually matters.
Concord air quality FAQ
What is the air quality in Concord right now?
As of September 14, 2026 at 8:09 AM EDT, the air quality in Concord, New Hampshire is AQI 29 — Good — with PM2.5 at 5.2 µg/m³, the median of 3 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Concord get ozone alerts in summer?
New Hampshire sits inside the Ozone Transport Region, a multi-state corridor where heat and regional traffic combine to push ground-level ozone higher. In late May 2024, an early heat wave triggered back-to-back DES ozone advisories for the state, with officials recommending sensitive groups skip outdoor exercise in the afternoon.
Does wildfire smoke reach Concord, New Hampshire?
Yes, increasingly. Six of New Hampshire's eight air quality alerts in summer 2025 were caused by smoke drifting down from Canadian wildfires rather than local pollution, and the same pattern showed up in 2023 and 2024. State officials now describe wildfire smoke as a routine part of New Hampshire summers rather than a rare event.
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 3 curated PurpleAir sensors Canairy tracks in and around Concord, 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 Concord
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