New approach for the characterization of the carbonaceous fraction in black crusts samples present on a granite substrate

This research deals with the characterization of black crusts collected from an historical building in the city of Vigo. Black crusts can be formed as a result of different chemical and physical reactions between the stone surface and environmental factors (such as gaseous pollutants and aerosol particulate matter, PM). The black crust can be considered as a passive sampler of pollutants. For this reason, in order to fully characterize those samples, several techniques were used such as: XRD, SEM-EDS, CHN, TGA, FT-IR/ATR and IC. This integrated approach allowed us to gain information about the mineralogical phases and the elements within the crusts giving the possibility to identify the pollution sources causing the stone decay within the buildings, as well as the variability in composition depending on the exposure of the analyzed surfaces.