The decay of natural building stone in an urban atmosphere like that of Vienna is mainly due to the attack of different air pollutants, especially with regard to the highly porous calcitic sandstones and limestones predominantly used in buildings and monuments in and around the city. As air pollutants appear not only as gases but also as aerosols, and sulfurous components may be the most important but by no means the only ones attacking a carbonatic building stone, studies on the combined effects of different air pollutants on stone weathering in the laboratory seem to be very important in this connection. The main effort of artificial weathering must of course always be to produce damage similar to that found outside in a natural environment. Therefore, at least in the first stage, a comparison with the nature and progress of stone corrosion in a steadily recorded urban atmosphere is desirable. This is the subject of Research Project Nr. 4836 supported by the Fonds zur Förderung der wissenschaftlichen Forschung in Österreich , which started at the beginning of 1983. In a specially developed climate chamber, chemical weathering of natural stones under various conditions is simulated. Besides, corrosion progress of exposed stone samples at different sites in the city of Vienna is investigated, measuring simultaneously the immission rates of air pollutants. The first results show that sulfatic aerosol deposition on stone surfaces might be ineffective in contrast to sulfurous gases, and that sulfation of calcitic stone material may be initiated in iron containing minor constituents such as marly inclusions. Finally, further proposals are discussed in this work.