Performance Evaluation of Photocatalyst Coating Systems Under Outdoor Exposure Condition Tatsuo Inukai＊1　Kenji Motohashi＊2 キーワード Durability, Outdoor exposure test, Photocatalyst, Soiling, Titanium dioxide 概要 This paper introduces the results of two series of experiments. In the first series of experiments, the effect of photocatalyst was confirmed through the decomposition of methylene blue in the laboratory by using ceramic tiles treated with titanium oxide. The effect was also confirmed after some degradation treatments for the tiles such as immersion into acid solution, immersion into alkaline solution, and sunshine carbon irradiation. In the next series of experiments, the outdoor exposure test under the pastoral and polluted ambient areas were conducted for the various exterior finishing materials treated with titanium dioxide. *1　Tsukuba Building Test Laboratory, Center for Better living *2　Building Research Institute, Dr. Eng. 9th International Conference on Durability of Building Materials and Components, March 2002