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The issue of environment protection, including the conservation of the monumental heritage worldwide, is related to atmospheric pollution, and its future therefore depends on air pollutant reduction. Carbonaceous particles emitted by combustion processes are the main factors responsible for the blackening of buildings. The identification and evaluation of the carbon species constituting the noncarbonate fraction of total carbon in damage layers, particularly in urban areas, are required in orderto investigate atmospheric deposition on building surfaces. Since noncarbonate carbon contains organic and elemental carbon originating from various human activities, its measurement and speciation are crucial to the protection and conservation of monuments and ancient masonry, playing an important role both in the proposal of mitigation strategies and in the definition of conservation treatments. The availability of a correct, accurate, and reproducible analytical method for a complete carbon balance is essential in studying the effects of atmospheric pollutants on the environment, including those affecting cultural heritage. A chemical-thermal methodology was set up, and its sensitivity, accuracy, repeatability, and reproducibility were tested on appropriate standard samples of composition similar to the black crusts on stones and mortars. The results indicate thatthe technique satisfactorily distinguishes among carbon species, particularly those of anthropogenic origin, allowing a reliable evaluation of their quantities in damage layers. In view of the difficulties encountered in applying the thermo-optical methods adopted for the measurement of carbon filters, the proposed methodology contributes to filling the current gap in suitable and reliable analytical procedures in the field of cultural heritage protection.

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The interaction between carbonaceous particles and stones used in historic buildings and monuments was investigated in a laboratory exposure system. Simulation experiments were carried out in a flow chamber where temperature, relative humidity, and SO2 concentration were controlled. Samples of carbonate stones (Carrara marble, Travertine, and Trani stone) were exposed for 150 days in air with 3 ppm of SO2 concentration at 25°C and 95% relative humidity. The stone specimens were coated with three types of carbonaceous particles (P1, P2, and P3) collected at the emission points of three oil‐fueled combustion sources: one centralized domestic heating plant and two electricity generating stations. For comparison, particles of activated carbon and graphite were also deposited on the stone samples. After exposure, samples were analyzed by X ray diffraction and infrared spectroscopy to identify the main chemical species, by ion chromatography to quantify SO4= and SO3= concentrations, and also by scanning electron microscope. The results show that the amount of SO4= formed increases in the presence of carbonaceous particles and is related to their heavy metal content.

The effects of carbonaceous particles and heavy metals in the interaction between sulfur dioxide and mortars were investigated in a laboratory exposure system. Simulation experiments were carried out in a flow chamber where temperature, relative humidity and SO 2 concentration were controlled. Samples of lime, pozzolan and cement mortars were exposed for 150 days in air with 3 ppm of SO 2 concentration at 25~ and 95% P,.H. The mortar specimens were coated with three types of carbonaceous particles, collected at the emission points of three oil-fueled combustion sources, and, for comparison, with particles of active carbon, pure graphite, iron oxide and vanadium oxide. After exposure, the mortar samples were analyzed by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIP,.) to identify the main chemical species, by ion chromatography (IC) to quantify SO;-and SOy-concentrations, and also by scanning electron microscope (SEM). The results show that the amount of SO 4--forming increases in the presence of carbonaceous particles and is related to their heavy metal content. iiiiiiiii!i~i~i R SUME