An experimental setup for in situ infrared reflection absorption spectroscopy (IRAS) studies of atmospheric corrosion of confined metal surfaces is described. Information about the drying process of confined metal surfaces and the chemical composition and growth rate of the corrosion products in the confinement was obtained during exposure to periodic wet-dry conditions. The drying process and the formation of corrosion products during periodic wet-dry conditions with different CO2 concentrations was studied. The decrease of the water bands from the water on the zinc surface was followed and the drying time of the confinement was approximately 6-8 h. The formation of corrosion products during the drying period was followed with in situ IRAS. The corrosion product formed under these conditions was mainly composed of ZnO with a smaller amount of Zn-5(OH)(8)Cl-2 . H2O with <5 ppm CO2 concentration in the air. When the CO2 concentration was 350 ppm, Zn-5(OH)(6)(CO3)(2) and Zn-5(OH)(8)Cl-2 . H2O were the dominant species in the corrosion product. With increasing CO2 concentration the amount of chloride precipitated as Zn-5(OH)(8)Cl-2 . H2O increased. This can be explained by the neutralization of the surface electrolyte by CO2 resulting in the precipitation of insoluble Zn-5(OH)(8)Cl-2 . H2O and Zn-5(OH)(6)(CO3)(2).