Dispersion and photochemical oxidation of reduced sulfur compounds in and around a large industrial complex in Korea

In this study, the environmental behavior of reduced sulfur compounds (RSCs: H2S, DMS, CS2, DMDS, and CH3SH) was investigated in an area influenced by strong anthropogenic processes based on a numerical modeling approach. The RSC emission concentrations were measured from multiple locations around the Ban-Wall industrial complex (BWIC) in the city of An San (AS), Korea, during a series of field campaigns held between August 2004 and September 2005. These emissions were then used as input for a CALPUFF dispersion model with the 34 dominant chemical reactions for RSCs. The impact of RSC emission on SO2 concentrations was assessed further in the study areas. The model study indicated the possibility that RSCs emitted in and around the BWIC can exert a direct impact on the ambient SO2 concentration levels in its surrounding areas with the most prominent effect observed during summer. Our prediction indicated that a significant fraction of SO2 was produced photochemically in and around the BWIC during the summer (about 30% of total SO2 concentrations) and fall events (∼20%). These photochemical productions of SO2 were mainly ascribable to H2S (∼60% of total contributions) and DMDS (∼25%) out of all five target RSCs. Meteorological contribution (dispersion) to SO2 concentration level was also highest during summer.