Airborne Observations of Wildfire Aerosols and Trace Gases Near Red Lake, Ontario

Wildfires are both a consequence of and a contributor to extreme weather events. Their increasing frequency and intensity release large quantities of aerosol particles and trace gases into the atmosphere, influencing atmospheric chemistry, cloud formation, and radiative forcing. These emissions can affect regional air quality and contribute to climate forcing on broader spatial scales. Understanding the composition and evolution of wildfire plumes is therefore essential for improving atmospheric and climate models.
Recent studies have emphasized the importance of measuring both gaseous and particulate components of wildfire emissions. Greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), and water vapor (H₂O) provide insight into combustion processes and plume transport. At the same time, aerosol properties—including particle size distributions, concentrations, single scattering albedo (SSA), and refractory black carbon (rBC) concentrations—play a key role in determining the radiative effects of wildfire smoke. Airborne measurements provide a unique opportunity to directly sample wildfire plumes and track their evolution over large spatial scales.
Despite recent advances, in-situ observations of wildfire aerosols and gases remain relatively limited. Many previous studies rely primarily on ground-based or satellite measurements, which often lack the vertical resolution and detailed characterization of wildfire emissions required to fully capture plume structure and aging processes.
Here, we present results from an aircraft-based field campaign conducted in July 2025 near Red Lake, Ontario, Canada. Measurements were performed aboard the National Research Council Canada’s Twin Otter research aircraft, equipped with a suite of atmospheric instruments. Gaseous measurements included CO₂, CH₄, and H₂O, while aerosol observations included particle size distributions, concentrations, SSA, and refractory black carbon. A thermo-denuder experiment was also used to identify non-rBC particles associated with ash or char, providing new insight into the evolution of wildfire emissions during atmospheric transport.