Photocatalytic air treatment process under room light

A process for photocatalytically decontaminating a room having an interior defined by enclosing surfaces including vertical walls and a ceiling, comprising:

• covering at least a part of the enclosing surfaces of said room with a thin film of photocatalytic semiconductor material having a band gap energy;
• disposing in the room an electric lamp for emitting visible light with sufficient intensity to illuminate the room with said visible light, said lamp emitting substantially no wavelength component of less than 300 nm and emitting ultraviolet radiation having an energy higher than the band gap energy of said semiconductor material in an amount effective to photoexcite said thin film;
• and
• energizing said lamp to illuminate said room and to simultaneously impinge said ultraviolet radiation upon said thin film with an intensity of 0.001-1 mW/cm.sup.2, to thereby photoexcite said thin film with said ultraviolet radiation whereby contaminants brought into contact with said thin film are photodecomposed upon illumination of said room.

A process for photocatalytically cleaning a surface of a fixture located in a toilet room, said toilet room having an interior defined by enclosing surfaces including vertical walls and a ceiling, said process comprising:

• covering at least a part of the surface of said fixture with a thin film of photocatalytic semiconductor material;
• disposing an electric lamp in the toilet room for emitting visible light with sufficient intensity to illuminate the toilet room with visible light, for emitting substantially no wavelength component of less than 300 nm and for emitting ultraviolet radiation having an energy higher than the band gap energy of said semiconductor materials in an amount effective to photoexcite said thin film;
• and
• energizing said lamp to illuminate the toilet room with visible light and to simultaneously impinge said ultraviolet radiation upon said thin film with an intensity of 0.001-1 mW/cm.sup.2, to thereby photoexcite said thin film with said ultraviolet radiation whereby contaminants deposited onto said fixture are photodecomposed as said lamp is energized.