AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
SimpleGAMMA: Reduced Mechanism for Aqueous Aerosol SOA Modeling
Joseph Woo, V. FAYE MCNEILL, Columbia University
Abstract Number: 662 Working Group: Aerosol Chemistry
Abstract Recently, the McNeill Group developed the Gas-Aerosol Model for Mechanism Analysis (GAMMA), a zero-dimensional kinetic model that couples gas- and aqueous aerosol-phase chemistry for speciated prediction of SOA and organosulfate formation in the aqueous aerosol phase under ambient or laboratory conditions. Results from GAMMA simulations (McNeill et al. ES&T 2012) indicate that, under low-NOx conditions, organosulfate and aqueous-phase SOA formation is dominated by IEPOX ring-opening chemistry. In urban (high-NOx) environments, aaSOA is primarily formed via reversible glyoxal uptake. This suggests that it is possible to model the great majority of aqueous aerosol phase SOA mass using a highly simplified reaction scheme which is computationally efficient and suitable for coupling with larger-scale atmospheric chemistry models. We have therefore developed an abridged version of GAMMA, simpleGAMMA.m, which reduces the total number of tracked aqueous species from ~75 to 5 and the number of species partitioning between the gas and aqueous aerosol phases to 2 (glyoxal and IEPOX). Agreement (to within 40% of predicted SOA mass) between simpleGAMMA and the full version of GAMMA is observed under all conditions tested (between pH 1-4 and RH 40-80%), after 12 hours of simulation.