Development of a new procedure for the assessment of particulate matter (PM) carbonaceous fraction on stone materials exposed to atmospheric pollution

The present study deals with the set-up and development of a new methodology to quantify the carbonaceous fraction (i.e., OC, organic carbon and EC, elemental carbon) in black crusts samples present on marble stone surfaces of historical buildings and monuments exposed to outdoor pollution. It is worth noting that OC and EC represent one of the main fractions of atmospheric particulate matter and, mainly EC, is responsible for the black colour of the crusts. The same method has been applied to resuspend known quantities of atmospheric particulate matter on marble mock-up specimens suitably realized to study the crusts' formation process starting from known quantities of the precursors in the formation process, i.e., PM and SO2, and submitting them to an accelerated aging process.