Hazardous air pollutant emissions estimates from wildfires in the wildland urban interface

Title	Hazardous air pollutant emissions estimates from wildfires in the wildland urban interface
Authors	Amara L Holder, Aranya Ahmed, Jeffrey M Vukovich, Venkatesh Rao
Magazine	PNAS Nexus
Date	06/20/2023
DOI	10.1093/pnasnexus/pgad186
Introduction	Fires occurring in the wildland urban interface (WUI) frequently involve the combustion of structures, vehicles, and their contents, alongside natural biomass. Given their proximity to populated areas, the emissions from these fires can significantly affect public health. This underscores the need for a thorough understanding of the criteria and hazardous air pollutants released from WUI fires, distinguishing them from traditional wildland fires. Prior investigations into the combustion toxicity of building and vehicle materials have demonstrated that urban fires generate numerous toxic substances. These include hydrogen cyanide, hydrogen fluoride, hydrogen chloride, isocyanates, polycyclic aromatic hydrocarbons (PAHs), dioxins and furans, as well as various toxic organic compounds like benzene, toluene, xylenes, styrene, and formaldehyde, along with metals such as lead, chromium, cadmium, and arsenic. Our research systematically reviewed existing literature to compile a compendium of emission factors for compounds released from burning building and vehicle materials. We then compared these factors with those from wildland fires, observing that emission factors for certain toxic species, including PAHs and some organic compounds, were several orders of magnitude higher than those from wildfires. Utilizing this compendium, we developed an initial estimate of emissions from several prominent WUI fires across the western United States. This analysis indicates that urban fuels contribute a substantial portion of toxic emissions to the atmosphere. Nevertheless, significant gaps persist in our knowledge regarding the specific fuel composition, consumption rates, and combustion conditions in WUI fires, which currently limit our capacity to accurately assess their full environmental and health impact.
Quote	Amara L Holder, Aranya Ahmed and Jeffrey M Vukovich et al. Hazardous air pollutant emissions estimates from wildfires in the wildland urban interface. PNAS Nexus. 2023. Vol. 2(6). DOI: 10.1093/pnasnexus/pgad186
Element	Hydrogen (H) , Fluorine (F) , Chromium (Cr) , Arsenic (As) , Carbon (C) , Nitrogen (N) , Oxygen (O)
Industry	Automotive , Chemical & Pharmacy , Research & Laboratory