DESC: Effective at capturing 99.97 percent of airborne particles as small as 0.1 micron in size, this air purifier features a permanently charged HEPAtech Electret filter for more thorough cleaning. Designed for rooms up to 15 by 16 feet, the unit changes the air up to six times per hour, while a built-in ionizer, with a separate on/off switch, distributes negative ions throughout the room to enhance the cleaning process. The air purifier has an advanced activated carbon pre-filter that reduces cooking, tobacco, and pet odors, and its CADR-certified rating is 165 for dust, smoke, and pollen. Other convenient features include a whisper-quiet three-speed fan, a filter-change indicator, and a portable, space-saving design that allows the unit to be easily placed flush against a wall or in the corner.