AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Chamber Simulation of Photooxidation of Dimethyl Sulfide and Isoprene in the Presence of NOx
Tianyi Chen, MYOSEON JANG, University of Florida
Abstract Number: 172 Working Group: Aerosol Chemistry
Abstract In the kinetic model of this study, to advance the photooxidation of DMS in the gas phase, the most recently reported reactions with their rate constants have been included. To improve the model predictability for the formation of sulfuric acid and MSA, heterogeneous reactions of gaseous DMS products [e.g., dimethyl sulfoxide (DMSO)] on the surface of aerosol have also been newly included in the kinetic model. DMS was photoirradiated in the presence of NO$_(x) using a 2 m$^(3) Teflon film chamber. The resulting chamber data was simulated using the new kinetic model. The model predicted that concentrations of both MSA and H2SO4 would significantly increase due to heterogeneous chemistry included in this study and this was well substantiated with experimental data. The model used in this study also well predicted the decay of DMS, the formation of other gaseous products such as SO$_(2) dimethyl sulfone (DMSO$_(2)), and the ozone formation linked to NO$_(x) cycle. To study the effect of coexisting volatile organic compounds, the photooxidation of DMS in the presence of isoprene and NO$_(x) has been simulated using the new kinetic model integrated with the Master Chemical Mechanism (MCM) for isoprene oxidation, and compared to chamber data. Both the model simulation and the experimental data showed an increase in the yields of MSA and H$_(2)SO$_(4) as the isoprene concentration increased.