Atmospheric aerosol particles represent the most uncertain aspect of air quality control issues and the broader climate system. Models routinely underpredict formation, mass loadings, and temporal trends of anthropogenic organic aerosol (OA). As a result of climate change, more frequent forest wildfires have become a major source of primary organic aerosol (POA), secondary organic aerosol (SOA) and associated volatile organic compounds (VOCs). Although many studies investigated sources, formation, and atmospheric aging mechanisms of OA attributed to a range of biomass fuels, the increased frequency of the most devastating wildfire events occurring at the wildland-urban interface imply that the amount, composition and properties of OA are controlled not only by burning biomass, but also by burning a range of engineered man-made materials. This project aims to perform molecular characterization of the chemical composition of OA samples collected during planned experiments at the National Institute of Standards and Technology National Fire Research Laboratory (NIST-NFRL) test facility simulating smoke emissions in the wildland-urban interface fire events and will conduct fire measurements on real-scale objects, such as entire furnished rooms. The team will perform the first molecular characterization experiments on various types of particulate matter emitted during NFRL test burns. This work will provide important input for closure studies focused on the source apportionment of POA; understanding of recursors and formation mechanism of SOA, chemical transformations, and aging of OA; understanding of composition of light-absorbing components in OA (i.e. brown carbon).