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Development of Volatility Distributions of Biomass Burning Organic Emissions
ADITYA SINHA, Ingrid George, Amara Holder, Michael Hays, Andrew Grieshop, North Carolina State University
Abstract Number: 561
Working Group: Combustion
Abstract
The volatility distribution of organic emissions from biomass burning and other combustion sources is a key property in determining their atmospheric evolution due to partitioning and aging. The gap between measurements and models predicting secondary organic aerosol (SOA) has been attributed to the absence of semi- and intermediate volatility organic compound (S/IVOC) measurements. The contribution of S/IVOCs from biomass burning emissions, a significant source of atmospheric OA burden, often quantified via the volatility basis set (VBS) framework, is not well understood. There is uncertainty in the amount and composition of S/IVOCs and how they are influenced by factors like fuel type and combustion conditions. To address this, we collected sorbent tubes and quartz fiber filter samples from biomass burning experiments using a range of fuels and combustion approaches. The tube with inset filter is subsequently analyzed using thermal desorption gas chromatography-mass spectrometry (TD-GC-MS) for targeted and non-targeted analysis of compounds with a wide range of volatilities (saturation concentration, C* ranging 10^(-3)-10^7 μg/m3). We project VOC and S/IVOC measurements onto the VBS framework to gain insight into the gas-particle partitioning from woodstoves used for domestic heating, in-situ and simulated open burning and biomass cookstoves used in developing country households. Comparisons across sources indicate similar distributions for open and prescribed burns and are consistent with distributions from literature. We noted deviations in distributions for woodstove emissions with 20% in the particle phase at lower OA concentrations (<25μg/m3) compared to ∼40% for other fire types. These distributions were derived assuming compounds eluting at the same time as reference alkane standards have similar response factors as well. Current work involves validation testing with different classes of compounds (PAHs, methoxy-phenols etc.) to constrain distributions.