The effects of atmospheric pollutants on the deterioration of stone work in Venice was studied during 1972-74 by measuring aerosol composition and HC1 and SOub>2 concentrations. Aerosol acidity, sulfate particulate matter, and SOub>2 concentrations showed seasonal variations; that of SOub>2 being the most significant due to variations in meteorological conditions and urban and industrial output. Microscopic and microchemical analysis of the stonework showed crack formation to occur by two processes; penetration by Hub>2SOub>4 containing solutions and NaC1 and crystallization of soluble salts.