The GermGuardian AC4010E, 3-in-1 Table Top Air Purifier is the perfect air cleaning system to have in the home or office, and is ideal for small and medium size rooms. It is more than just a filter and has many levels of cleaning to help improve indoor air quality. Here’s how it works: A True HEPA filter captures up to 99.97 percent of airborne particles as small as . 3 microns in size, such as dust mites, mold spores, plant pollens, and pet dander. Titanium Dioxide (Tio2) in the combination filter is activated by the UV light to help fight the growth of bacteria, germs, and mold and decompose odor molecules caused by smoking, cooking, and pets. According to the American Academy of Pediatrics Allergy & Immunology, doctors recommend HEPA air filtration systems to reduce exposure to indoor asthma triggers.