GILDES, a computer-based model of atmospheric corrosion, has been used to simulate copper exposed at room temperature to 200 ppb SO2 in combination with either NO2 or O-3 at different concentrations. The GILDES model involves the five most important regimes in atmospheric corrosion (gas, liquid, deposition, electrodic, and surface) and includes 27 aqueous species and more than 60 aqueous reactions. Under these exposure conditions copper forms cuprite (Cu2O) and various copper sulfates in both SO2 + NO2 and SO2 + O-3 mixtures, and copper hydroxynitrate in SO2 + NO2 after an incubation time of 4 h. Among these experimental observations the GILDES model correctly predicts the formation of copper sulfate (in both SO2 + O-3 and SO2 + NO2 mixtures) and copper hydroxynitrate (SO2 + NO2). It is furthermore able to predict the formation rate of copper sulfate in SO2 + O-3 mixtures, but not the formation rate of copper sulfate and copper hydroxynitrate in SO2 + NO2 mixtures. (c) 2005 The Electrochemical Society.