Sulfur dioxide, present in the atmospheres of agricultural production, is an active stimulator of corrosion processes. We studied the protective effectiveness of compositions based on rapeseed oil (RM) and Emulgin as a corrosion inhibitor (CI) in the corrosion of carbon steel St3 in a 0.5 M NaCl solution in equilibrium with sulfur dioxide depending on the exposure time of the electrodes in the working environment. Model atmospheres were created in sealed plastic containers. The initial concentration of sulfur dioxide in the range from 0.1 to 10 vol.%, the ratio of the volumes of the gas and liquid phases, equal to 1.4 were chosen. It has been established from viscosity-temperature curves that Emulgin has a thickening effect in relation to PM, due to the formation of micellar structures. It has been established that the mass transfer of moisture through the oil films of RM with Emulgin increases with an increase in the SO2 concentration and the duration of the experiment and decreases with an increase in the Emulgin concentration. The corrosion rate of carbon steel in the gas and liquid phases increases with an increase in the initial concentration of sulfur dioxide in the air. It has been established that films of non-inhibited PM provide the protective effectiveness of carbon steel in a 0.5 M NaCl solution in equilibrium with the gas phase, containing up to 0.001 vol.% sulfur dioxide, in 92-93%. 7 - 10 wt.% Emulgin, it is advisable to introduce into the protective film at an equilibrium concentration of sulfur dioxide in the gas phase of more than 0.001 vol. %.