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an important site of degradation. The discoloration or "frosting" of latex paints was reported to be caused by the concentration of sulfur dioxide, nitrogen oxide, or hydrogen sulfide pollutants. Strength losses in wood may be caused by hydrolytic degradation of the hemicelluloses and a sulfonation reaction of the lignin. Acid deposition on nylon shortens the potential service life for outdoor fabrics. Interestingly, light accelerates the attack of atmospheric sulf uric acid on nylon. The strong program on Metallic Corrosion clearly indicated that the conventional classification of environments into marine, industrial, and rural is no longer adequate. In addition to corrosion of cultural resources such as bronze statues, the discussions covered the corrosion of automobiles, reinforcing steel, bridges and other architectural materials, and indoor equipment. The effect of acid deposition on the corrosion behavior of many specific steels and other materials was reported. The effects of certain enviroments were also addressed. The particularly severe automotive environment in the Northeast United States, for example, is due to the combination of acid deposition and the use of road de-icing salts. The session, Economic Effects, reported on the methods used to assess the costs of materials degradation due to acid deposition, and on the difficulty in accurately assessing these costs. Also discussed was the response of manufacturers and householders to pollutant-induced damages. The economic costs are potentially huge, given the ubiquitous nature of exposed buildings, infrastructure components such as bridges and transmission towers, and cultural resources. The irreversibility of the damage is most important when considering cultural resources. In the United States, costs of metallic corrosion associated with acid deposition were assessed at 0.15% of the GNP, or about $5 billion in 1984. Economic damages to building materials alone were estimated at $2 billion annually. Based upon this presentation, the annual cost of materials degradation by acid deposition in the United States is over $5 billion and could be as high as $25 billion. Summary While the Symposium provided much information on the wide range of materials affected by acid deposition, it became evident that there is much to be done regarding future research and funding. For example, only 2.5% of the budge of the National Acid Precipitation Assessment Program is directed toward the study of materials degradation. A better understanding of the nature and mechanisms of materials damage by acid deposition could reduce or even eliminate this type of damage, and would lead to
huge annual dollar savings. The Symposium proceedings will be published as a volume in the American Chemical Society Symposium Series.
32nd International Field Emission Symposium George Smith Oxford University
The 32nd International Field Emission Symposium (IFES) was held in Wheeling, West Virginia, July 14-19, 1985. The symposium was organized by Professor S. S. Brenner, Department of Metall
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