The CREON 2000 effectively uses ultra violet light. Because the patented CREON 2000 process makes the rays of the ultra violet light part of the system, which is installed in the air ducts and is shielded by the duct walls, the light is directed only at the harmful microbes circulating through the system and, when the system is properly installed, will not be dangerous to anyone in its proximity. Q: Other ultraviolet air cleaners on the market lose their effectiveness after a few weeks of use. How does the CREON 2000 maintain effectiveness consistently? With other ultraviolet air cleaners, the dust is attracted to the bulb and attaches to it, much as metal is drawn to a magnet. The surface of the bulb gradually accumulates dust and blocks out the UV light, which diminishes its effectiveness. To keep those systems working, their bulbs must be cleaned often. In contrast, the CREON 2000 has a unique built-in air dynamics light protection system that prevents the settling of dust particles