NASA's Goddard Earth Observing System model tracked wildfire-produced brown carbon across North America from July 14 through July 20, showing smoke moving through Canada and the United States.
Brown carbon is organic aerosol emitted by fires and a component of wildfire PM2.5. It contributes to the yellow, orange and brown tint of smoke plumes.
The GEOS system assimilates observations from satellites, aircraft and ground instruments with temperature, moisture and wind data. The resulting animation is a model reconstruction, not a camera recording or a single satellite image.
More than 180 fires were active in Ontario on July 14, NASA reported, along with several in northern Minnesota. Winds carried smoke southeast by the following day.
Air quality declined from southern Ontario into the Upper Midwest and Northeast. NASA said Detroit remained in the hazardous range for several consecutive days, while Toronto, Chicago, New York and Washington ranged from unhealthy to hazardous.
Smoke continued to affect the Great Lakes region on July 19 and 20. Storms improved air quality in parts of the East as fires in the Pacific Northwest began degrading conditions there.
The brown-carbon field in the animation represents organic carbon specifically attributed to wildfire smoke. Wildfires also emit black carbon, but black carbon has substantial vehicle and industrial sources that complicate attribution.
A NASA model update in February 2026 separated anthropogenic and biomass-burning organic carbon, allowing the animation to isolate wildfire brown carbon more directly than earlier versions.
The reconstruction explains where modeled smoke moved during one completed week; it is not a current forecast. Current health decisions require local official air-quality readings and advisories rather than the July animation.