Ultraviolet light reduces the growth of odor-causing microbes on the surface of the TruSens Air Purifier filter, allowing the reduction of odorous gases and a prolonged lifespan for the filter itself. Bacteria, viruses, mold spores and protozoa that are drawn in by the 360° filtration of the Z2000 are exposed to the germicidal wavelengths of UV light, and are rendered incapable of reproducing and infecting. The TruSens Air Purifier Replacement UV Bulb works with the TruSens Filter to draw in air from all directions, collecting pollutants such as basic household odors and airborne allergens. Dual Airflow and HEPA filtration act in tandem to collect all airborne pollutants and purge the entire room of harmful, airborne bacteria! The dynamic design allows the TruSens replacement uv bulb to last a lengthy 2-3 years, meaning you won't need to change it out very often. The indicator light on the Z2000 lets you know when it's time for a new bulb. Simply replace and resume purified air! TruSens Air Purifiers are available in 3 different models that correspond to room size. The Z2000 Air Purifier is meant for medium rooms up to 375 square feet (34.8 square meters). Clear your air with TruSens!