Quantitative data on carbon fractions in interpretation of black crusts and soiling on European built haritage

There is wide recognition of the pivotal role of gaseous multi-pollutants and aerosols in determining the damage encountered on monuments and built cultural heritage in European cities. The main effects of atmospheric pollution on building materials in urban areas are soiling and black crusts formation. Furthermore, anthropogenic pollutants have changed over time, and attention now focuses on the contribution to damage layer formation of particles, particularly soot/carbonaceous ones, whose importance in determining air quality in urban areas is steadily increasing. However, the analytical tools and currently available data remain inadequate to attain a correct approach to black crust characterization and identification of causes of damage: there is a pressing need to discriminate and quantify the pollutant amounts, particularly that of carbonaceous aerosols, which deposit and accumulate on monuments and building surfaces, giving rise to surface blackening. The present work makes a contribution to filling this gap by presenting data on carbon fraction speciation and concentrations, obtained from the application of a specific analytical methodology on black surface layers in different European cities. As well as providing a preliminary data base, the information obtained turn out to offer some insight into past, present and future pollutant sources contributing to the damage on the built heritage.