Chemical relations between atmospheric aerosols, deposition and stone decay layers on historic buildings at the mediterranean coast

To evaluate the effects of the environment on weathering of historical buildings in the Mediterranean Basin, an elaborate study has been carried out at four monuments, with specific interest directed on the action of air pollution and marine salts. The composition of the atmosphere around the monuments has been investigated by monitoring the aerosols and the total deposition. These results are combined with the stone decay phenomena to interpret the deterioration at the respective monuments. In Eleusis, Greece, a highly industrialized area, high concentrations of heavy metals and sulphate are found in the aerosols and deposition and in the decay layers of the stone, while the marine influence is obscured, in spite of its location close to the sea. In Malta and in Cadiz (Spain), the influence of the sea dominates in the stone weathering process. In Bari (Italy), next to the effects of marine aerosols on the stone decay inside and outside the building, high concentrations of sulphate are observed on the outside stones. The aerosols and depositions reflect a relatively small influence of anthropogenic derived elements; this points out the action of gaseous SO2 on the stones.