A new analytic methodology for the characterization of the carbonaceous fraction in black crusts present on stone surfaces

The aim of this research work is the development of a method to characterize and quantify the various components present in the black crusts that due to atmospheric pollution have developed on the surfaces of buildings and monuments. The carbonaceous fraction is the main cause of blackening of architectural surfaces and is involved in black crusts formation. A new methodology based on the use of TGA/DSC and CHN analysis has been set up in this work allowing easily to determine organic carbon (OC) and elemental carbon (EC). Four standard samples were prepared, with the aim to simulates black crusts composition, and analysed with the set-up methodology in order to validate it. The new method has been subsequently applied to the analysis of real crusts samples from monuments and buildings placed in cities heavily affected by atmospheric pollution.