Abstract View
Simulating Wall-free Aromatic Secondary Organic Aerosol Formation via Multiphase Reactions in the Presence of Electrolytic Inorganic Aerosol
SANGHEE HAN, Myoseon Jang, Chufan Zhou, University of Florida
Abstract Number: 531
Working Group: Aerosol Chemistry
Abstract
The impact of the Teflon reactor wall on aromatic secondary organic aerosol (SOA) formation are explicitly simulated by using the Unified Partitioning Aerosol Phase Reaction (UNIPAR) model integrated with the gas-wall partitioning (GWP) model. The formation of oxygenated semivolatile organic compounds (SVOCs) from the photooxidation of ten different aromatic hydrocarbons is simulated by using an explicit gas-kinetic mechanism (MCM v3.3.1). In the model, SVOC’s GWP and gas-particle partitioning onto preexisting particulate matter are kinetically processed with the absorption and desorption kinetics. The UNIPAR model simulates aerosol growth via the oligomerization of reactive SVOCs in both organic phase and aqueous reactions containing electrolytic inorganic salts. For the GWP model, GWP coefficient and the deposition rate constant of SVOCs are predicted by using a quantitative structure activity relationship (QSAR) employing SVOCs’ physicochemical descriptors. This GWP model is then incorporated with the UNIPAR model in the DSMACC-KPP platform and simulated SOA chamber data. The UNIPAR-GWP model simulates SOA data obtained using UF-APHOR chamber varying NOx levels, humidity, temperature, and seed conditions. In the absence of aqueous reactions, the underestimation of SOA due to GWP is significant raging 25% and 65% at the high NOx levels (HC ppbC/NOx ppb =3). In the presence of wet-inorganic seed, the impact of GWP on SOA was much small owing to rapid reactions of organic species in the aqueous phase.