The Honeywell true HEPA Allergen remover Tower is perfect for medium-large rooms. Its stylish design and slim profile allow it to be placed anywhere, even in tight spots. The true HEPA filter effectively captures up to 99.97 percent of the following allergens and particles: dust, pollen, pet dander, dust mite debris and smoke.* It also reduces odors, VOCs (volatile organic compounds), and certain germs. How the air purifier works: a fan continuously draws in airborne pollutants. The dirty air passes through the activated carbon Pre-Filter that traps large particles and absorbs VOCs, gases and odors. The air then passes through the HEPA filter that captures the really small particles*. The filtered, cleaner and fresher smelling air is then circulated back into the room. Disclaimers: *From the air that passes through the filter, 0.3 microns and larger.