Renee McVay is collaborating with Joost de Gouw and members of the NOAA ESRL Chemical Sciences Division to model secondary organic aerosol (SOA) formation during wildfires with the regional model WRF-Chem. Biomass burning is the largest contributor to organic aerosol emissions globally, which have important climate and health consequences. Aerosols are either emitted directly (primary organic aerosols) or formed via gas-to-particle conversion during ageing of smoke plumes (SOA). The potential of wildfires to form SOA is still very uncertain. McVay will be working to update SOA formation in WRF-Chem by including non-traditional pathways to SOA, such as aqueous-phase reactions, that have heretofore been neglected but have the potential to form significant SOA. These updates will be constrained by environmental chamber experiments. Simulations using the updated WRF-Chem will be compared to field measurements of organic aerosols in wildfires as part of the Fire Influence on Regional and Global Environments Experiment (FIREX) campaign. This project will enhance understanding of SOA formation during wildfires and the dependence of this formation on chemical and meteorological conditions. This knowledge will enable better predictions of air quality, weather, and climate effects of wildfires. The updated WRF-Chem model will also be useful to fire managers and first responders for weather forecasting during wildfires.