| 摘要 |
PROBLEM TO BE SOLVED: To provide a concrete block which can clean contaminated air without requiring a large area for installation or without damaging the appearance. SOLUTION: The concrete block 2 consists of an aerated concrete block 4 and a surface layer 6 formed on the side face of the block. The surface of the block 4 has lots of recesses and projections 10. The surface layer 6 is formed by spraying a mixture of titanium dioxide (TiO2 ), cement, filler and water on the side face 4A to form a thin layer so that the surface of the layer 6 is formed into a rough surface 12 following up the surface state 10. In a daytime, when the surface layer 6 is irradiated with sun rays, titanium dioxide causes photocatalytic reaction to change nitrogen oxides into nitric acid as a final state by the photocatalytic reaction and nitrogen oxides are maintained as nitric acid on the surface layer 6. The contaminant such as nitric acid held on the surface layer 6 is washed out and removed from the surface layer 6 by rain. |
