This study examines the local oxidation chemistry of reduced sulfur compounds (RSC) in the urban air. The chemical conversion of RSC (such as DMS, $CS_2,;H_2S,;DMDS,;and;CH_3SH);to;SO_2$ was modeled using a photochemical box model. For our model prediction of the RSC oxidation, measurements were carried out from an urban monitoring station in Seoul (37.6$^{circ}$N, 127.0$^{circ}$E), Korea for three separate time periods (Sep. 17~18; Oct 23; and Oct. 27~28, 2003). The results of our measurements indicated that DMS and $H_2S$ were the dominant RSC with their concentrations of 370${pm}$140 and 110${pm}$60 pptv, respectively. The conversion of DMDS to $SO_2$ can occur efficiently in comparison to other RSC, but it is not abundant enough to affect their cycles. The overall results of our study indicate that the photochemical conversion of the RSC can contribute ≶ 20% of the observed $SO_2$.