AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Organic Aerosol-sulfate Interaction: Evaluation of Thermodynamic Effects
GAUTHAM SEKAR, Shunsuke Nakao, Clarkson University
Abstract Number: 652 Working Group: Aerosols, Clouds, and Climate
Abstract Recent studies suggest that biogenic SOA formation is enhanced by anthropogenic emissions. One of the possible mechanisms is the interaction between organics and sulfate. A number of experimental studies investigated organic-inorganic interaction through chamber experiments using different kinds of seed particles in different conditions. However, the complex interplay of thermodynamics and kinetics of organic-inorganic containing system, such as effects of water, pH, sulfate, ionic-strength, mass-transfer, remains uncertain.
We aim at improving the understanding of thermodynamics of organic aerosol-sulfate interaction with the focus on salting-in and salting-out, theoretically and experimentally. In order to reduce complexities of coupled thermodynamics and kinetics in typical chamber experiments, we will develop a new experimental approach that isolates thermodynamic partitioning between external mixtures of aerosol within a smog chamber. Hygroscopicity measurements will be used to track partitioning of organics into inorganic particles. We developed a theoretical emulator of size-resolved cloud condensation nuclei measurements to evaluate feasibility of the new approach. We will present results of proof-of-concept experiments and comparison with the emulator model. We will use AIOMFAC model to estimate activity coefficients of organic-sulfate-water mixture.