Burning "ExposHome": Deriving a Mixture of Combustible Materials in American Homes at the Wildland-Urban Interface for Health Studies.

Approximately 39% of U.S. homes are now located in the Wildland-Urban Interface (WUI) and are at elevated risk of burning during wildfires. WUI fires emit a cocktail of chemicals from the combustion of anthropogenic materials, including compounds that may differ from the burning of biogenic-only materials. There is currently limited knowledge on the mixture composition of combustible materials in WUI homes, representing a data gap and need to further characterize exposure chemistries and toxicological impacts of WUI-relevant smoke exposures. To address this issue, this study integrated combustible materials in an average American WUI home to derive what we are referring to as the "Burning ExposHome." Items such as structural materials, plumbing, furnishings, and appliances were included in the Burning ExposHome. Calculations were based on an average American household, a 2,016 sq. ft. single family home of four bedrooms, using materials typical to California due to the high incidence of WUI fires in that geographic region. All materials were sorted and summed by type of base material such as wood materials, plastics, textiles, and metals. This list is notably modular and detailed per item, allowing for the addition/subtraction of components to address future study designs. In summary, the total combustible mass of an average American home was around 46,500 kg, including 81% wood materials, 6% plastics, and 2% metals. This list of materials serves as a foundational mixture of home materials to integrate into exposure characterization, mechanistic toxicology, and ecological/human health research addressing wildfires occurring at the growing WUI.