Impact of Acid Deposition on Materials for Cultural Properties in East Asia

摘要

The impact of wet and dry deposition of acid components to cultural properties was investigated on several materials: bronze, copper, carbon steel, marble etc., by exposing under indoor and outdoor conditions at regional levels in East Asia. The corrosion rates of copper were constant to long exposure period in all sites. Copper is very useful for complex air pollution index. The copper damage in Japan was affected by natural factors, such as meteorological conditions and sea salt. However, the damage in China and South Korea was significantly influenced by pollution factors, such as SO_2 in air. The deposition flux of S and Cl was involved in the damage of copper in Japan, however, the flux of S contributed largely to the degradation in China. SO_2 gas was absorbed in the wet surface of copper and S was deposited there. However, few S could be supplied from SO_4~- in rainfall to the surface of copper. Rainfall would clean up there. The material damage was more serious in China than in other countries.