Honeywell 50150 Permanent True HEPA Round Air Purifier The 50150 True HEPA air purifier removes at least 99.97 of common household particles as small as 0.3 microns from the air passing through it such as dust pollen mould spores tobacco smoke and cat dander. The carbon prefilter helps remove common household odors while helping to extend the life of the HEPA filter. The patented 360 degree air intake and discharge maximizes efficiency circulating the air and allowing for placement in any area of your room. This air purifier also features the IntelliCheck filter monitor to remind you when to replace the filters.