Acidic Deposition: State of Science and Technology. Report 21. Distribution of Materials Potentially at Risk from Acidic Deposition

摘要

One of the adverse effects of acids deposited from the atmosphere is the degradation of material surfaces. It is axiomatic that NAPAP's assessment requires a description (with broad temporal and spatial components) of the material surfaces that may be at risk. The document provides an account of the research activities that have been preformed in recent years toward this end, as well as new data collected and analyzed for this purpose. The report is configured in two sections: Section 1 deals with modern construction materials; Section 2, with cultural resources. The distinction is required because of fundamental differences between the two classes of materials. These differences include the rationales for selection of materials for various applications, their geographic patterns of use in relation to the pattern of atmospheric acidity, and the methods required to evaluate the societal costs of damage. An evaluation of the impacts of continuing deposition of acids on those resources deemed to require definite preservation will require consideration of current conditions based on past exposures and the tolerance of exposed materials to further decay.