The Vornado AQS15 Air Purifier uses Vortex technology, exclusive to Vornado, to circulate clean air throughout the entire room(s). Because if the air isn't being circulated, the air cleaner is only cleaning the immediate area around the unit. This home air cleaner actually does 6 air changes per hour in an area of up to 230 sq. ft.! The Vornado AQS15 uses HEPA filtration which removes up to 99.97% of airborne pollutants including: pollen, dust, mold spores, pet dander, smoke, odors and more. Uses a two-stage filtration with a PreSorb® prefilter which confines larger particles before air continues through the HEPA filter. Both filters are disposable and easy to replace. Ideal for use in nurseries, bedrooms and offices. Does not emit ozone.