D200 In-Duct Dual lamp PCO Photocatalytic Oxidation UV Air Purifier The D200 Kills up to 99.9% of existing mold, mildew and airborne viruses and will prevent them from ever growing again and spreading. By killing and preventing airborne contaminants you will be less susceptible to allergies, asthma, breathing problems, headaches, dizziness, neurological problems and other long-term health problems caused by mold, mildew and airborne viruses. The D200 utilizes Photo-Catalytic Oxidation, the combination of Ultraviolet (UV) light and Titanium Dioxide (TIO2), to kill volatile organic compounds (VOC) in the air as they pass through the D200 before they enter the duct system and spread throughout your home or office.