In July 2026, wildland fire activity surged across Canada, coinciding with the typical increase in lightning ignitions. According to a seasonal outlook published by multiple fire departments in North America, the resulting fires generated significant smoke plumes that impacted air quality in both the U.S. and Canada.
This animation illustrates the movement of brown carbon, an organic aerosol produced by wildfires that gives smoke its distinctive yellow, orange, and brown colors. Lignite serves as the primary component of fire PM2.5 emissions, a type of air pollutant known to exacerbate cardiovascular and respiratory issues. The smoke plume is shown hovering over North American skies from July 14 to July 20, 2026.
The animation utilizes data from the Geos (Goddard Earth Observing System) model, integrating inputs from satellites, aircraft, and ground-based observations. This model combines satellite imagery of aerosols and fires with meteorological data—including temperature, humidity, and wind—to forecast plume dynamics.
As the animation begins on July 14, numerous fires have already ignited, including significant activity in Ontario and northern Minnesota. Winds carried the smoke southeastward, resulting in overcast skies. By July 15, air quality deteriorated across southern Ontario and parts of the upper Midwest and northeastern U.S. On July 16 and 17, air quality dropped to hazardous levels in cities like Detroit, remaining critically low for several consecutive days. In metropolitan areas such as Toronto, Chicago, New York City, and Washington, D.C., air quality fell within the range of unhealthy to dangerous.
On July 19 and 20, smoke continued to adversely affect air quality across the Great Lakes region, according to the national weather bureau. However, storms in parts of the East began to clear the air, improving air quality to good to moderate levels. Meanwhile, wildfire activity was causing air quality to decline in the Pacific Northwest.
In this animation, brown carbon specifically denotes organic carbon emitted from wildfire smoke. In addition to brown carbon, wildfires also release black carbon or soot, contributing to PM2.5 levels. Although black carbon serves as a tracer in smoke plumes, it also originates from human activities like vehicle emissions and industrial processes. The GEOS models have been enhanced to differentiate between brown carbon from biomass combustion and anthropogenic sources from February 2026 onward, as detailed in this update.
This NASA Earth Observatory animation was created by Lauren Dauphin, utilizing Geos FP data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Kathryn Hansen.
- Conversation (July 16, 2026) Yes, breathing wildfire smoke can be harmful to your health – here’s what you can do to protect yourself. Accessed July 21, 2026.
- NASA Global Modeling and Assimilation Office (February 19, 2026) Split between anthropogenic and biomass combustion sources of organic carbon in GOCART-2G. Accessed July 21, 2026.
- NASA’s Science Visualization Studio (July 20, 2026) 2026 Long-distance transport of Canadian wildfire smoke to the United States (July 14-20, 2026). Accessed July 21, 2026.
- National Interagency Fire Centre, Natural Resources Canada, National Weather Service (July 14, 2026) Assessment and outlook for seasonal fires in North America. Accessed July 21, 2026.
- New York Times (July 19, 2026) When will the wildfire smoke clear?. Accessed July 21, 2026.
- U.S. Environmental Protection Agency (July 14-20, 2026) AirNow: Air Quality Interactive Map. Accessed July 21, 2026.
Source: science.nasa.gov