Sulfur dioxide (SO2) and carbon dioxide (CO2) emissions have to be efficiently controlled due to environmental, economic and social demands. An interesting approach for SO, and CO2 separation/concentration is the use of supported ionic liquid membranes (SILMs). Ionic liquids (ILs) are very interesting compounds for this application since they have a negligible vapour pressure, leading to high stability and reducing solvent losses by volatilization to the gas stream. pIn this work, the permeabilities of air, CO2 and 10 vol.% SO2-air have been obtained using different SILMs. The permeability of air is one order of magnitude lower than CO2 permeability and it is also lower than the permeability of the mixture of air and 10 vol.% SO2. In addition, the selectivities of CO2 and the SO2 mixture have been obtained.