Wildland fire activity in Canada decided to ramp up in July 2026 - right on schedule for lightning ignition season, according to a seasonal outlook from several North American fire agencies that probably wished they were wrong. The blazes sent smoke plumes pouring across the U.S. and Canada, making air quality everyone's least favorite topic.

This animation tracks brown carbon, the organic aerosols emitted by fires that give smoke plumes their characteristic yellow, orange, and brown tint - nature's way of accessorizing with pollutants. Brown carbon is a major component of a fire’s PM2.5 emissions, a type of air pollution that can aggravate cardiovascular and respiratory conditions, because why not add insult to injury? The plume drifts across North American skies from July 14 through July 20, 2026, courtesy of data from a version of the GEOS (Goddard Earth Observing System) model, which assimilates data from satellites, aircraft, and ground-based observing systems. In addition to satellite observations of aerosols and fires, the model also incorporates meteorological data such as air temperature, moisture, and winds to project the plume’s behavior - because predicting misery is a science.

On July 14, at the start of the animation, numerous fires had already cropped up, including more than 180 in Ontario and several in northern Minnesota. Winds carried the smoke southeast, and by July 15, skies turned hazy and air quality declined from southern Ontario in Canada to the Upper Midwest and Northeast in the U.S. July 16 and 17 saw air quality in many areas continue to plummet, including in Detroit, where it stayed in the hazardous range for several consecutive days - a new record nobody was aiming for. Toronto, Chicago, New York City, and Washington, D.C., saw air quality ranging from unhealthy to hazardous.

On July 19 and 20, smoke continued to affect air quality downwind, including in the Great Lakes region, according to the National Weather Service. Storms began clearing it away in parts of the East, where air quality improved to good or moderate - finally, a break. Meanwhile, fires in the Pacific Northwest began degrading air quality there, because the West Coast doesn't deserve nice things either.

The brown carbon shown in this animation represents organic carbon that comes specifically from wildfire smoke. Wildfires also emit black carbon, or soot, which contributes to their PM2.5 output. Black carbon has long served as a tracer for smoke plumes, but human sources - such as vehicle exhaust and industrial combustion - produce it too, blending in with the black carbon from fires. The GEOS model has been able to make that distinction for brown carbon since February 2026, when an update enabled it to split organic carbon into its anthropogenic and biomass-burning components - because even pollution needs a clear identity.