Dose-response functions as estimates of the effect of acid precipitates on materials

This paper presents a brief summary of the findings of the 8-year exposure program of the European Economic Commission, United Nations (UN EEC), on estimating the effect of acid precipitates on materials, including historical and cultural monuments. Presented and discussed are dose-response functions for structural metals and alloys (bronze, copper, weathering steel, zinc, aluminum, nickel and tin), stone materials (limestone and sandstone), paint coatings and glasses. The effects of dry and wet precipitates are discriminated and expressed as separate doze-response functions. The corrosion damage to the majority of materials is most of all aggravated by dry precipitates of sulfur dioxide, while copper and tin suffer concurrently from ozone. In the equations the term pertaining to the dry precipitates includes a complex temperature effect. Unlike the correlations obtained upon four years of tests, the new functions include an exposure time parameter which enables one to calculate the corrosion rate at any period of time and to estimate the service life of the object at a given critical rate of corrosion.