Isotopic analysis of black crust samples from the Monza Cathedral (Italy): a preliminary study

The degradation of historical buildings surfaces through the formation of black crusts is a process mainly related to air pollution. The origin of air pollutants can be determined by measuring the stable isotope ratio of their main elements. In this study, the results obtained from the isotopic analysis of BCs taken from the historical Monza cathedral, an important monument placed in Monza, a highly polluted city of Northen Italy, are discussed. In particular, stable isotope ratios of carbon, sulphur and oxygen of two black crust samples (namely MD and MS) were measured by Isotope Ratio Mass Spectroscopy. The obtained δ13C, δ34S and δ18O values suggest that anthropogenic pollution is responsible for the formation of black crusts on the façade of this cathedral.