Vornado AC1-0038-43 AC350 True HEPA Filter Whole Room Air Purifier, Up To 220 SQFTThe Vornado AC350 Whole Room Air Purifier uses true HEPA filtration, the most effective filtration available, to remove up to 99. 97% of airborne allergens down to 0. 3 micron 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 AC350 uses a radial blower to intake and clean all the air in the room