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Impact of Dilution Temperature on Size-Resolved Aerosol Emissions from Lignocellulosic Biomass
LUKE MCLAUGHLIN, Erica Belmont, University of Wyoming
Abstract Number: 192
Working Group: Combustion
Abstract
Biomass burning events, such as wildland fires and prescribed burns, are complex combustion phenomena consisting of four main stages: pyrolysis, flaming combustion, primary char oxidation, and smoldering. These fire events produce significant amounts of particulate matter which influence global radiative forcing, decrease air quality and visibility, and have negative health impacts. Biomass burning aerosol emissions consist predominantly of elemental carbon and organic carbon, the quantity, size distribution, and volatility of which are influenced by the combustion mode and ensuing dilution process of the emissions mixing into ambient air. As the number and size of wildland fires increase each year, and as prescribed burning is used as a forest fire management technique across the United States, there is an increased need to characterize the quantity, size, and volatility of the emissions from burning lignocellulosic biomass to better understand environmental and health effects. This work examined the emissions from lignocellulosic biomass and its major constituents under laboratory pyrolysis conditions to understand biomass composition and dilution temperature influences on aerosol formation. The major constituents of lignocellulosic biomass were pyrolyzed and the resultant aerosol emissions were characterized in terms of particle size, quantity, and volatility under variable dilution temperatures and at a fixed dilution ratio and rate. The aerosol emissions formed from the biomass constituents were then compared to those of wood and grass biomasses, and an additive model for predicting characteristics of biomass burning emissions from the behavior of individual constituents was assessed. Results showed a significant influence of dilution temperature on particle size, number, and distribution, with the nucleation mode of particle formation dominating at low dilution temperatures. The additive model performed well in predicting the trends and magnitude of aerosol emissions from native biomass samples with variable lignocellulosic constituent distributions.