Black crusts grown on varied stone substrata from historical buildings under different air quality scenarios (SE and NW Spain)

This work addresses the characterization of black crusts (BCs) collected from stones of different nature, i.e. granite and carbonate stones (limestone, marble and travertine) taken from diverse historical buildings located in NW (Vigo) and SE (Granada) Spain subjected to dissimilar environmental and air quality scenarios. Likewise, filters located adjacent to the sampling areas were analyzed to evaluate particle dry deposition components in order to assess the ambient air quality of the selected buildings and its impact on the growth of BCs (natural passive pollutants markers). To this end an array of complementary analytical techniques was used, i.e.: Stereomicroscopy (SM), Polarized Light Microscopy (PLM), High-Resolution Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (HRSEM-EDX), X-ray Diffraction (XRD) and Fourier Transform-Infrared spectroscopy (FT-IR).