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Development of Volatility Distributions of Biomass Burning Organic Emissions
Citation:
Sinha, A., I. George, A. Holder, M. Hays, AND A. Grieshop. Development of Volatility Distributions of Biomass Burning Organic Emissions. American Association for Aerosol Research Annual Conference, Portland, Oregon, October 14 - 18, 2019.
Impact/Purpose:
One of the major challenges in air quality modeling science is the ability to accurately predict the formation of secondary organic aerosol. Generally, these models have been underpredicting the amount of these organic particles that are produced through atmospheric reactions of primary emissions. One of the major reasons for these discrepancies is the lack of accurate measurements intermediate and semi-volatile components of biomass burning emissions. In this work, different types of biomass burning emissions will be characterized on a volatility basis to generate more accurate accounting of gas-phase organic emissions contributing to SOA. This work will improve air quality modeling predictions of SOA formation from biomass burning emissions.
Description:
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 and analyzed them using thermal desorption gas chromatography-mass spectrometry (TD-GC-MS) for targeted and non-targeted analysis of compounds with a wide range of volatilities. Current research involves using the volatile organic carbon (VOC) and S/IVOC measurements from these experiments and projecting them onto the VBS framework to understand gas-particle partitioning from these sources. We will develop volatility distributions of the organic emissions from woodstoves used for domestic heating, samples from in-situ and simulated open burning, and biomass cookstoves used in developing country households. We will conduct comparisons of VBS distributions within and across these sources to explore variability and identify any commonalities. We will also explore variation across the various fuel types, modified combustion efficiencies and appliance types and compare with speciated measurements and previous VBS distributions from the literature. The resulting volatility distributions and associated emission factors can be used to update emission inventories and simulate the gas-particle partitioning of biomass burning in chemical transport models.