Composition and Chemistry of Crusts on Stone

This chapter will look at the composition of the crusts that disfigure our cultural heritage, particularly those developing on carbonate stones, focusing on their mineralogy, concentration of soluble salts and carbon fractions, with the aim of identifying the major pollution sources casing their formation. The changes in air pollution can be shown when comparison of modern soiling with historic black crusts is done in terms of mineralogy and geochemical characterization will also be discussed.