Titanium dioxide (in powder form) is a shiny white solid substance that is used as a pigment in paints and paper. When heated, it turns yellow and when cooled, it regains its original white colour. In daylight it turns into a semicunductor and is therefore used in solar cells to convert solar energy into electricity. The advantages for concrete elements using titanium oxide include their better resistance to weather conditions, self-cleaning concrete surface, and its brighter and lighter look. The evidence also show that such a concrete surface binds nitrogen compounds from the air under the influence of UV radiation and thus cleanses the environment.