Numerous papers deal with the weathering of lime-containing building stones exposed to atmospherical sulphur oxides. The presence of such air pollutants is closely connected to the consumption of fossil fuels. Up to now it has only been possible to bring partial light upon aspects of the processes taking place during this type of action. Difficulties often result from the shortage of suitable methods to characterize quantitatively a rock and the changes in itby means of physical characteristic values, and also from the lack of a standard to which the data obtained may be compared. Of interest too is the question of how far artificial weathering results correspond to the actual behavior of the exposed rock on the outside of a building, and the question of how useful and reliable preservation measures are. Moreover, the role of media acting physically and chemically in the pore space are discussed, along with the phenomenological particularities of weathering profiles formed in the surface zone of the building stone as a result of attack by SO₂. In th is paper an attempt is made to give as complete as possible a state-of-the-art report in this field, evaluating literature and using personal judgement in order to provide a basis for further investigations.