Black crusts collected from monuments and historic buildings were analyzed. The analytical methodology adopted involved a preliminary characterization or the samples by means of X-ny diffraction (XRD). optical microscopy (OM) and scanning electron microscopy (SEM-EDAX). The anions present were quantified using ion chromatography (IC). Differential thermal analysis (DTA) and thermogravimetric analysis (TGA), combined with combustion techniques, allowed the quantification of the products of degradation and atmospheric deposition. In addition. the carbon of atmospheric origin was identified and quantified in its carbonate, non-carbonate, elemental and organic fractions.