Photocatalytic Oxidation (PCO) is a reaction that occurs when Titanium Dioxide (TiO2) is exposed to ultraviolet (UV) light rays. When VOCs, gaseous contaminants, and odors come into contact with the PRO-Cell™ surface, they are converted to odorless, harmless water vapor and Carbon Dioxide. The titanium dioxide catalyst is activated by UV light which neutralizes biological contaminants such as bacteria, viruses, mold and fungi. When used properly, PCO is a powerful air sanitizer ideal for controlling air quality.