ABSTRACT
The physical, chemical and mineralogical characteristics of sandstone surfaces are changed by the depositing of dusts as well as gaseous and liquid pollutants from the air or from rainfall which react with the dusts or with the substrate. Measurements of immission rates of the single pollutants Danneker (1986), Kraus (1985), Krumbein (1988), Mirwald (1986), as well as investigations of crusts from different historical monuments Blaschke (1986), show that physico-chemical as well as chemicalbiological processes are initiated by the concentration of pollutants which destroy the original surface of the sandstone or change it in a negative way. A layman can recognize this from the changes of colour, surface structure and the outer appearance. In order to stop the weathering process the detrimental substances have to be removed and further measures have to be undertaken.
