Emissions and Atmospheric Chemistry of Furanoids from Biomass Burning: Insights from Laboratory to Atmospheric Observations

Abstract

Furanoids are a class of reactive volatile organic compounds that are major products from the pyrolysis and combustion of biomass polymers, including cellulose, hemicellulose, and lignin. Biomass burning is an atmospheric source of furanoids that is increasing in frequency and intensity throughout regions of the world. Once emitted to the atmosphere, furanoids may react with the major atmospheric oxidants to form secondary pollutants that are hazardous to human health, including ozone (O 3 ) and secondary organic aerosol (SOA). This review is a comprehensive assessment of the literature between 1977 and the present describing the emissions and atmospheric fate of furanoids emitted from wild, prescribed, and domestic fires. The review is organized by presenting the physical properties of key furanoids first, followed by a summary of the biopolymer pyrolysis and combustion reactions that lead to furanoid formation. Next, furanoid emissions factors are compiled across the typical fuels consumed by biomass burning to highlight the key species emitted in smoke. We next review the available kinetic and atmospheric degradation mechanism data that characterize the reaction rates, gas-phase products, and SOA formed as a result of furanoid reactions with OH, NO 3 , O 3 , and Cl radicals. We then describe studies that have focused on evaluating furanoid atmospheric chemistry and their impacts on air quality using a combination of field observations and model simulations. We conclude with a perspective that identifies future research directions that would address key data gaps and improve the understanding of furanoid atmospheric processes.