Deterioration of pentelic marble, Portland limestone and baumberger sandstone in laboratory exposures to gaseous nitric acid

The effects of gaseous nitric acid on three calcareous stones (Pentelic marble, Portland limestone and Baumberger sandstone), used extensively in historic buildings, have been investigated under different conditions of relative humidity, mass of stone, nitric acid concentration, grain size of stone and flow rate of nitric acid mixture. It was found that all three stones are good sinks for gaseous nitric acid. Pentelic marble proved to be more vulnerable at relatively high humidities in spite of its low porosity. The other two stones behave similarly in spite of the difference in their chemical constitutions. Apparently this difference is counterbalanced by their great difference in porosity.