A WashU research team spent 45 days traveling to different wildfire locations in the western United States where they sampled gaseous smoke and aerosol species and analyzed their chemical and optical properties. This research was conducted as part of the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign, a joint venture led by NOAA and NASA.

The researchers led by Rajan Chakrabarty, the Harold D. Jolley Career Development Associate Professor in the Department of Energy, Environmental & Chemical Engineering, found that wildfires are causing a much greater warming effect than has been accounted for by climate scientists. They discovered the role of “dark brown carbon” emitted from wildfires, which is an abundant but previously unknown class of particles.

From the sampling of ground and airborne smoke, the team encountered dark brown carbon as a strong light absorber, or climate heater, highlighting a need to revise climate models.