Présence constante de cendres volantes industrielles dans les croûtes noires d'altération superficielle de monuments français en calcaire compact

The fly-ash contents of the weathering black-crusts of six French monuments in compact limestone, located in diversely polluted environments, were studied by Analytical Scanning Electron Microscopy. They are compared to those from ambiant air of one monument and to those sampled in the electrostatic precipitators of two EDF power stations, coal and heavy oil-fired. The various fly-ash populations are comparable in granulometry, morphology and elementary chemical composition. Their role in growth of weathering black crusts cannot be neglected