Ice and snow are common materials in the environment and reactions over ice surfaces have some significant impact to the atmosphere. Aimed to understand atmospheric S(IV) oxidation processes near ice/snow surfaces and bromine deactivation/activation, we have studied SO2 uptake on HOX-treated ice surfaces and oxalic acid on ice. The study has been carried out in a flow reactor at 190-240 K. Uptake coefficients were determined as a function of surface coverage, temperature, and ice film thickness. Kinetic results are discussed in terms of the Eley-Rideal mechanism. This study suggests that the uptake of SO2 is enhanced by the presence of HOBr or HOCl molecules near the ice surface.