Acidic deposition: State of science and technology. Report 19. Effects of acidic deposition on materials. Final report

All materials that are exposed to the outdoor environment are subject to degradation caused by natural weathering processes. Since the mid-19th century, air pollution has been suspected of accelerating the degradation of natural and man-made materials. Wet and dry acidic deposition, alone or combined with other air pollutants, probably contributes to this increased rate of damage. The goal of research concerning the effects of acidic deposition on material surfaces is to quantify an incremental effects due to wet and dry deposition of hydrogen ion, sulfur dioxide, and nitrogen oxides on mass loss and other forms of alteration. The goal has been pursued by the NAPAP both in the field and in laboratory test chamber experiments. It is the purpose of the report to review the literature on the impact of acidic deposition on the materials selected by the NAPAP for study, and to report the results of the NAPAP experimental research program on the chemical and physical processes that related to the impact of pollutants on material surfaces. The materials selected for study under the NAPAP program included zinc/galvanized steel and other metals, carbonate stone (as monuments and building facings), and surface coatings (paints).