A two-year exposure program of Portland stone and Monk's Park stone at 25 sites in southeast England revealed significant differences in weight losses, changes in surface roughness and chemistry at each location that can be attributed to the activity of air pollutants and salts. In particular it was shown that weight loss of exposed samples can be attributed to both solution and sulfation (the latter probably contributing an average of at least 39% for Portland stone, 44% of Monk's Park stone); that salt attack of sheltered samples is evident at Bletchley (brickmaking) and coastal locations; and surface roughness changes, measured by <i>Ra</i> values on a Surfcom plotter, appear to be particularly sensitive to processes of surface disruption, such as salt weathering. Analysis of SO₂ data at the sites showed significantly higher concentrations at London sites. The corresponding gradient in weight loss was gentler, probably as the result of the influence of other atmospheric variables. -- AATA