A diffusion technique for the evaluation of surface reactivity: application to the study of SO2 deposition on marble

A svstem has been developed for studying the reactivity of marble. From measurement of SO2 concentration, a reactivity coefficient and the corresponding deposition velocity bave been calculated. As an example of the usefulness of the method, the reactìon of marble with SO2 alone and SO2+NO2 has been investigated. An enhancement on the deposition of SO2 has been found when SO2 and NO2 bave been combined at high relative humidity (r.h. = 90%), at lower relative humidity (r.h. = 50%), NO2 does not affect the rate of SO2 reaction on this surface.