SmokeDarChicago wildfire smoke and air quality
Live readings for Chicago, Illinois: whether wildfire smoke is overhead, what the surface air measures, and how the next five days look. Free, no signup, no ads.
How smoke reaches Chicago
Most wildfire smoke over Chicago arrives on northwest winds from fires burning in Canada, hundreds to thousands of kilometers upwind. The lake breeze complicates the picture: air flowing off Lake Michigan can hold surface readings down even while a dense plume rides overhead, which is why the sky and the AQI so often disagree here. That is why SmokeDar reports two numbers for Chicago: smoke aloft (modeled aerosol optical depth from Copernicus CAMS) and surface air (PM2.5 and US AQI, observed AirNow monitor data when a monitor is nearby). They are different things, and they often disagree.
What the numbers mean
AQI 0–50 is good and 51–100 is moderate; ordinary days. From 101–150, sensitive groups (kids, older adults, pregnant people, anyone with heart or lung conditions) should shorten hard outdoor exercise. Above 150, everyone should cut both time and intensity outdoors. The full playbook is in the Smoke Guide.