Zróżnicowanie procesów deterioracji elewacji piaskowcowej XIX-wiecznego budynku Archiwum Państwowego w Poznaniu

Stone has been used in architecture since Antiquity. The processes of its deterioration in different buildings have always been associated with natural processes of its weathering (physical, chemical, biological). However, this situation has changed over centuries. Currently, air pollution (mainly in urbanised areas) has a significant impact on the accelerated weathering of stone monuments. The research presented in this paper concerns the deterioration of stone facade of the 19th century building of the National Archive in Poznań, where the latest factor (contemporary air pollution) plays the greatest role. Based on the ICOMOS glossary, selected forms of deterioration were described and classified in macro and micro scales. For this purpose, optical and scanning microscopy and X-ray diffraction were used. As a result of the research, lichen species composition and secondary mineralisation in the black crust were identified. Elements, such as: barium, zinc, lead, and iron, which were detected on the black crust, were directly related to anthropogenic pollution caused mainly by combustion and low emissions.