The Vornado AC550 Whole Room Air Purifier uses true HEPA filtration, one of the most effective filters available, to remove up to 99.97% of airborne allergens down to .3 microns in size. The Vornado Whole Room Purifier actively circulates and filters all the air throughout a room. Without powerful circulation, the air cleaner is only cleaning the immediate area around the unit. The AC550 uses a radial blower to intake and clean all the air in a room – up to 335 sq. ft . Precision engineering allows the blower to operate quietly, despite its powerful air flow. The AC550 uses a combination of 2 HEPA and 2 carbon filters to trap Dust, Pollen, Pet Dander, Smoke, Bacteria, Mold Spores, Dust Mites, and more. The carbon prefilter both adsorbs odors and traps larger particles. When in ‘auto mode’, advanced dust sensing technology detects the level of dust in a room, fluctuating the cleaning cycle up or down, depending on the air quality. Features 4 speeds, push button electronic controls, filter replacement indicator, sleep mode and industry leading 5 year limited warranty. Two (2) True HEPA Filters (MD1-0022) and Two (2) Carbon Prefilters (MD1-0023) included. This product does not emit ozone.