Air Quality in Chicago, Illinois — Live
Live readings from PurpleAir sensors across Chicago — with free alerts the moment smoke drifts in.
AQI 38 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Chicago, Illinois is AQI 38 — Good and falling — with PM2.5 at 6.8 µg/m³, the median of 5 live PurpleAir sensors reading 27 to 44. 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 Chicago: 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 Chicago and Evanston, Oak Park, Cicero, Skokie. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Chicago
The sensors Canairy reads in Chicago agree right now — all 5 sit in the Good band, a 17-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 2.2 mi NNW | 38 | Good |
| 3.0 mi WNW | 43 | Good |
| 4.0 mi SSW | 27 | Good |
| 5.0 mi SW | 29 | Good |
| 6.1 mi NNW | 44 | Good |
For most of the year Chicago's air is ordinary big-city air, but the last few summers have shown how quickly that can change. Canadian wildfire smoke pushed the city to the worst air quality of any major city in the world in June 2023 and again in July 2026, while the everyday sources -- summer ozone off Lake Michigan, freight diesel, and heavy industry on the Southeast Side -- keep the metro area failing national clean-air grades even in calmer weeks.
What Canairy does for Chicago
A clear verdict
Not just a number — a plain-English call for Chicago: 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 Chicago or across the country, on one screen.
What the air in Chicago is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Moderate | ozone |
| Tomorrow | Good | ozone |
| Monday | Moderate | ozone |
| Tuesday | Moderate | ozone |
Forecast from EPA AirNow for the Chicago 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.
Canadian wildfire smoke is now a summer fact of life
On June 27, 2023, smoke from hundreds of wildfires burning across Quebec settled over Chicago and pushed the Air Quality Index to 228, deep in the very unhealthy range and the worst of any major city in the world that day. The National Weather Service declared air quality action days for the 27th and 28th, and the haze was thick enough to blur the skyline. At the time it felt like a once-in-a-generation event.
It was not. In July 2026, another round of Canadian smoke gave Chicago the worst air in the world again. The Park District closed every outdoor beach and pool and moved summer day camps indoors, outdoor sports leagues were called off, and in Waukegan the mayor ordered a mandatory beach evacuation. Two hazardous smoke summers in three years is why a lot of Chicagoans now check the air the way they check the forecast.
The lake gives you summer ozone, not just a cool breeze
Lake Michigan shapes Chicago's worst everyday air problem. On hot, sunny days the land breeze carries the city's tailpipe and smokestack pollution out over the water, where it bakes in the sun into ground-level ozone, and then the afternoon lake breeze pushes that ozone back onshore. The result is that shoreline neighborhoods and the communities just up the lake can see their highest ozone of the day in the afternoon, well downwind of where the pollution started.
This is a seasonal, roughly May-through-September pattern, and it is stubborn. The Chicago metro area is still classified as not meeting the EPA's 2015 health standard for ozone, and the American Lung Association's 2025 State of the Air report ranked Chicagoland 15th worst in the country for ozone with a failing grade and about 20 unhealthy ozone days a year. Ozone is invisible, so a hot, clear day can carry unhealthy air that never looks hazy.
The Southeast Side has carried an unfair share of the industry
Chicago's air is not the same across the city. The industrial corridor along the Calumet River on the Southeast Side has spent years fighting the byproducts of heavy industry -- first open-air piles of petcoke, a dusty petroleum-refining leftover stored beside homes, and then toxic manganese dust blowing off bulk-storage yards run by companies like S.H. Bell and Watco. Residents of the 10th Ward pushed the U.S. and Illinois EPAs to investigate and won tighter city rules on bulk storage.
These burdens land on predominantly Black and Latinx neighborhoods, which is why local groups treat it as an environmental justice issue and not just a pollution one. Add the freight rail yards and truck-heavy expressways that move goods through the region, and the diesel particulate load is real. A citywide number can look fine while the air a few blocks from a rail yard or storage facility reads much worse, which is exactly why a sensor near your own home tells you more than a regional average.
Chicago air quality FAQ
What is the air quality in Chicago right now?
As of September 5, 2026 at 7:10 AM CDT, the air quality in Chicago, Illinois is AQI 38 — Good — with PM2.5 at 6.8 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Does Canadian wildfire smoke really reach Chicago?
Yes, and it has become a recurring summer problem. Smoke from wildfires in Quebec and Ontario pushed Chicago to the worst air quality of any major city in the world on June 27, 2023, when the AQI hit 228, and again in July 2026, when the city closed beaches and moved summer camps indoors. When the smoke arrives it can turn healthy air hazardous within hours, so live sensor readings are the fastest way to know whether it has reached your part of the city.
Why is Chicago's air worse on hot summer days even without smoke?
Much of it is ground-level ozone. On hot, sunny days the lake breeze off Lake Michigan carries the city's traffic and industrial pollution out over the water, where sunlight cooks it into ozone, then pushes it back onshore in the afternoon. The Chicago metro area still does not meet the EPA's ozone health standard, and ozone is invisible, so a clear day can carry unhealthy air that never looks hazy.
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 Chicago, 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 Chicago
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