Air Quality in St. Paul, Minnesota — Live
Live readings from PurpleAir sensors across St. Paul — with free alerts the moment smoke drifts in.
AQI 52 from 5 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in St. Paul, Minnesota is AQI 52 — Moderate and holding steady — with PM2.5 at 9.8 µg/m³, the median of 5 live PurpleAir sensors reading 51 to 58. Canairy's verdict: Mostly clear.
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 St. Paul: weeds pollen is the strongest of the three at a very 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 St. Paul and Minneapolis, Maplewood, Roseville, West St. Paul. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in St. Paul
The sensors Canairy reads in St. Paul agree right now — all 5 sit in the Moderate band, a 7-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.7 mi NE | 52 | Moderate |
| 4.5 mi WSW | 51 | Moderate |
| 5.4 mi SW | 56 | Moderate |
| 6.0 mi W | 53 | Moderate |
| 6.5 mi WSW | 58 | Moderate |
St. Paul's air is clean on most days, but the city sits first in line for the Canadian wildfire smoke that now rolls south into Minnesota nearly every summer. Since 2018 that smoke has become a regular feature of Twin Cities summers, and 2023 set a record with 27 air quality alert days across the metro. The rest of the story is closer to home: heavy traffic along the I-94 corridor and rising summer ozone that the state expects on a handful of warm days each year.
What Canairy does for St. Paul
A clear verdict
Not just a number — a plain-English call for St. Paul: 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 St. Paul or across the country, on one screen.
What the air in St. Paul is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 43 | Good | ozone |
| Tomorrow | — | Good | ozone |
| Monday | — | Good | ozone |
| Tuesday | — | Good | ozone |
| Wednesday | — | Good | ozone |
Wildfire activity across the western U.S. and Canada continues to wind down and smoke-free conditions are expected to continue across our region as we approach the end of summer. Low-level clouds have lingered across the Twin Cities longer than expected on Friday and this has kept ozone lower than was forecast yesterday. However, air quality may still reach the Yellow (Moderate) category across the southern Twin Cities suburbs on Friday. Air quality should remain in the Green (Good) category for the rest of the state. High pressure will build across Ontario on Saturday, and this will produce northeast winds across MN. Cooler and cleaner air will move into the region, and air quality should be in the Green category statewide Saturday. Widespread clouds and scattered thunderstorms will return to the region on Sunday and Monday. Air quality should remain in the Green category statewide through Monday.
Forecast from EPA AirNow for the Twin Cities 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.
St. Paul is first in line for Canadian smoke
Most of the smoke that turns St. Paul's sky the color of weak coffee starts hundreds or thousands of miles north, in the boreal forests of Canada, and rides a cold front down into Minnesota. State meteorologist Matt Taraldsen has said it is really being driven by climate change, both the fires in Canada and the fires here in Minnesota. The pattern has held every summer since 2018, and it has been getting worse: the Twin Cities logged a record 27 air quality alert days in 2023 and another 25 in 2024.
When the smoke is thick, the whole metro moves together. On July 15, 2026 the MPCA pushed the hazardous maroon alert into north central Minnesota while counties across the Twin Cities, St. Paul included, sat in the very unhealthy purple category. On days like that the number on this page can climb from Good into triple digits in a matter of hours, which is exactly when it helps to have something watching the sensors for you.
The I-94 corridor runs right through the city
St. Paul's other air-quality story is the freeway. Air pollution along the I-94 corridor between St. Paul and Minneapolis runs nearly three times worse than the level the MPCA calls unhealthy, and the agency has flagged 94 percent of that corridor as an area of concern for environmental justice. If you live, work, or send a child to school within a few blocks of the freeway, your everyday air can be measurably dirtier than the citywide average even on a clear, smoke-free day.
That burden is not new and it is not evenly shared. When I-94 was cut through St. Paul in the 1960s it displaced about 6,000 people and hundreds of businesses in the Rondo neighborhood, then home to roughly 80 percent of the city's Black residents. Studies of the metro have since found that lower-income areas and communities of color tend to sit with more traffic pollution even though those same residents drive less. A sensor a block from the interstate and one in a quiet residential pocket can read very differently, which is why the map below matters as much as the headline number.
Summer brings ozone, not just smoke
Wildfire smoke gets the headlines, but it is not the only thing that fouls St. Paul's summer air. Ground-level ozone forms on hot, sunny, stagnant days when sunlight cooks the exhaust from traffic and other sources, and it is invisible, so there is nothing to see the way there is with smoke. For 2026 the MPCA forecast 4 to 6 days when ozone could reach levels unhealthy for sensitive groups, which it described as slightly above Minnesota's historical average.
The two problems can also stack. The hottest, most stagnant stretches of a Minnesota summer are the same conditions that build ozone and that tend to trap wildfire smoke near the ground, so a bad-air day is often bad for more than one reason. The MPCA's overall outlook for 2026 was 12 to 16 smoke impact days on top of those ozone days. For someone with asthma or a heart condition, the practical question is simply whether today is one of them, which is the question this page is built to answer.
St. Paul air quality FAQ
What is the air quality in St. Paul right now?
As of September 5, 2026 at 2:41 PM CDT, the air quality in St. Paul, Minnesota is AQI 52 — Moderate — with PM2.5 at 9.8 µg/m³, the median of 5 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why does St. Paul get so much wildfire smoke?
Most of it is not local. Smoke from wildfires in Canada and northern Minnesota rides cold fronts south into the Twin Cities, and Minnesota sits close enough to the source that it arrives often. It has been a regular feature of St. Paul summers since 2018, and the metro set a record with 27 air quality alert days in 2023.
Is the air worse near I-94 in St. Paul?
It can be. The MPCA has measured air pollution along the I-94 corridor between St. Paul and Minneapolis at nearly three times the level it considers unhealthy, and it has flagged 94 percent of that corridor as an environmental justice area of concern. If you live near the freeway, checking the sensor closest to you on the map tells you more than the citywide number does.
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 St. Paul, 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 St. Paul
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