Emerging Pollutant Emissions from the Combustion of Built Materials

HONGRU SHEN, Bradley H. Isenor, Carolyn Liu-Kang, Mohamad H. Al-Jabiri, Rowshon Afroz, Amanda Hanashiro Moraes, Shakiba Talebian, Oscar Olfert, Ginny Marshall, Alex K.Y. Lee, Samar Moussa, Sumi Wren, Jeremy Wentzell, Amy Leithead, Jason S. Olfert, Ran Zhao, John Liggio, Arthur W. H. Chan, Jonathan Abbatt, University of Toronto

     Abstract Number: 93
     Working Group: Burning Questions of Aerosol Emissions, Chemistry, and Impacts from Wildland-Urban Interface (WUI) Fires

Abstract
Wildland-Urban Interface (WUI) fires are wildfires that spread into areas settled by humans, and their frequency and intensity have increased in recent years due to the rising number of wildfires and rapid urban expansion. These fires cause large-scale destruction of infrastructure and vehicles, degraded local and regional air quality, and significant health risks to emergency responders and surrounding communities. Unlike wildfires, which primarily burn natural materials, WUI fires can also involve a diverse range of built materials, including plastics, building insulation, and household furnishings. The combustion of these materials releases a more complex mixture of hazardous pollutants, many of which remain poorly understood in terms of their chemical composition and health impacts. During a fire lab campaign in the summer of 2024, the Biomass Burning in Canada (BBCan) project collected and burned common built materials, including polyester curtains, polyvinyl chloride (PVC) pipes, polystyrene (PS) insulation, and polyurethane (PU) foam. A suite of state-of-the-art online mass spectrometers, including a Soot Particle Aerosol Mass Spectrometer (SP-AMS), a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS), and an iodide Chemical Ionization Mass Spectrometer (I-CIMS), was employed to investigate the resulting airborne emissions. We identified and quantified the emissions of nanoplastic particles (NPPs), halogenated compounds, toxic gases, and other emerging pollutants. Emissions of NPPs were observed from PET burns, characterized by m/z 121, m/z 149, and m/z 166 in SP-AMS. In both PVC and PS burns, bromine-containing submicron particles were observed, likely to originate from additives present in building materials. Enhanced emissions of HCl were observed in PVC burns, with an estimated emission factor of 354-477 g kg-1. For PU burns, elevated emissions of HONO, HCN, and HCNO were detected, with estimated emission factors of 1.1±0.8 g kg^-1, 0.61±0.02 g kg^-1, and 0.064±0.001 g kg^-1, respectively. This study aims to advance the understanding of chemical composition, physical properties, and emission factors of WUI fire pollutants, providing data support for their climate and health impact assessment.