Air Quality in Ann Arbor, Michigan — Live
Live readings from PurpleAir sensors across Ann Arbor — with free alerts when summer ozone or wildfire smoke moves in.
AQI 9 from 5 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Ann Arbor, Michigan is AQI 9 — Good and holding steady — with PM2.5 at 1.7 µg/m³, the median of 5 live PurpleAir sensors reading 6 to 12. 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 Ann Arbor: weeds pollen is the strongest of the three at a high 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 Ann Arbor and Ypsilanti, Saline, Dexter, Chelsea. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Ann Arbor
The sensors Canairy reads in Ann Arbor agree right now — all 5 sit in the Good band, a 6-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.7 mi SE | 7 | Good |
| 2.7 mi WSW | 12 | Good |
| 2.8 mi WNW | 6 | Good |
| 3.3 mi E | 9 | Good |
| 3.5 mi W | 9 | Good |
Ann Arbor's air is good most of the year — the city sits inland in a forested stretch of the Huron River valley, without the mountains or coastal fog that trap pollution in other parts of the country. What actually moves the needle here is summer ground-level ozone from heat and traffic on the I-94 and US-23 corridors, and — as June 2023 showed — wildfire smoke that can blow in from hundreds of miles away in Canada.
What Canairy does for Ann Arbor
A clear verdict
Not just a number — a plain-English call for Ann Arbor: 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 Ann Arbor or across the country, on one screen.
Why did the sky turn hazy in June 2023?
In June 2023, smoke from wildfires burning across Quebec and Ontario rode unusual northeast winds down into the Great Lakes, and Michigan's Department of Environment, Great Lakes, and Energy (EGLE) issued the state's first-ever PM2.5-based air quality alert on June 4. Ann Arbor's own reading hit 109 on the AQI scale — Unhealthy for Sensitive Groups — while Benton Harbor and Kalamazoo climbed even higher, to 132.
It kept happening. By late June, EGLE had issued back-to-back ozone and smoke alerts for the seven-county Detroit metro area, including Washtenaw County, through June 29 and 30 — the first time the state had ever posted two different pollutant warnings for the same region at once. "This is hopefully not the new normal," EGLE senior meteorologist Jim Haywood said at the time. "This is hopefully an outlier. But we don't know."
Ozone, not smoke, is the more familiar problem
Most summers, Ann Arbor's air trouble has nothing to do with fire. Ground-level ozone forms when tailpipe exhaust and other emissions cook in strong sunlight and heat, and it builds fastest along busy corridors like I-94 and US-23, where traffic backs up through the city every day. The American Lung Association's State of the Air report gives the wider Detroit-Warren-Ann Arbor metro area a failing grade for ozone, and its 2026 edition found the number of high-ozone days climbing rather than falling.
Michigan calls these Air Quality Action Days: EGLE issues one whenever ground-level ozone is forecast to cross the federal health standard of 70 parts per billion averaged over eight hours, mostly on hot, still, sunny days from late spring through early fall. On those days the advice is the same one Canairy sends automatically — move the run indoors and give the afternoon heat a pass.
The city started watching its own air block by block
In 2022, Ann Arbor's Office of Sustainability and Innovations began running its own ambient air monitoring network rather than relying only on the state's handful of regional stations. By September 2025 it had grown to ten solar-powered Clarity Node-S sensors positioned around the city, each reading fine particulate matter (PM2.5), nitrogen dioxide, and ozone, with two also tracking temperature, humidity, and wind.
The point, in the city's own words, is "hyper-local access to variations in air quality throughout the city" — proof that one downtown reading doesn't describe what's happening in every neighborhood. That's the same idea behind Canairy's approach: instead of one number for the whole metro, we read the sensors nearest the places you've actually saved, whether that's a home near the Huron Parkway or a kid's school off Packard.
Ann Arbor air quality FAQ
What is the air quality in Ann Arbor right now?
As of September 14, 2026 at 12:27 PM EDT, the air quality in Ann Arbor, Michigan is AQI 9 — Good — with PM2.5 at 1.7 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why did Ann Arbor's air quality get so bad in June 2023?
Wildfire smoke from Quebec and Ontario rode unusual northeast winds into Michigan, and the state issued its first-ever PM2.5 air quality alert on June 4, 2023. Ann Arbor's AQI reached 109 — Unhealthy for Sensitive Groups — and by late June the state was posting simultaneous ozone and smoke alerts for the Detroit metro area, including Washtenaw County, for the first time ever.
Does Ann Arbor have an ozone problem in summer?
Yes, more so than wildfire smoke in a typical year. Heat and traffic along corridors like I-94 and US-23 cook up ground-level ozone on hot, sunny days, and the American Lung Association's State of the Air report gives the wider Detroit-Warren-Ann Arbor metro area a failing grade for it. Michigan issues an Air Quality Action Day whenever ozone is forecast to cross the federal health standard.
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 Ann Arbor, 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 Ann Arbor
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