Investigating carbonaceous aerosol in western wildfires from emissions to impacts

Fires and the aerosols that they emit impact air quality, health, and climate, but the abundance and properties of carbonaceous aerosol (both black carbon (BC) and organic aerosol (OA)) from biomass burning (BB) remain uncertain and poorly constrained. North America, in particular the western US, is one of the few regions in the world where more intense and frequent wildfires have been directly tied to climate change impacts. In this work, we use measurements of carbonaceous aerosol in the western US from the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen (WE-CAN) to constrain the GEOS-Chem model. We focus here on characterizing and improving upon uncertainties around smoke emissions and subsequent impacts on air quality and radiation. We show that the sampling of such heavily smoke-dominated regions challenges the ability of models to match observations of BC, OA, and CO concentrations. We also explore the evolution of smoke with age and other areas of uncertainty impacting our ability to model BB impacts (e.g., injection heights and optical properties).