Maps of damage to marble tombstones in the urban region of Philadelphia demonstrate a close spatial correspondence with airborne pollutant concentrations. Mean recession rates on upper tombstone faces are an order of magnitude greater (3.5 mm per century) in the center of the city than they are 20 km away in the suburbs and countrside (<0.5 mm per century). Not only are more pollutants emitted in the city, but they are also concentrated in the city center by centripetal air movement into the urban heat island. Gaseous SO 2 appears to be the most damaging pollutant, as is shown by the presence of gypsum in urban stones. Although rainfall is important in removing sulfate reaction products, anthropogenically-induced acid rain has only a minor role in marble deterioration. High urban SO 2 concentration cause sufficient gypsum accumulation within the stones to exfoliate the durable surface layer. Old photos of tombstones in central Philadelphia cemeteries show that exfoliation greatly accelerated between 1930 and 1960, concurrent with increases in SO 2 levels. Recent improvements in air quality are likely to have slowed stone deterioration. -- AATA