4-stage hospital-type filtration. Detects air quality and automatically adjusts the fan speed to keep your air purified. True HEPA filter with antimicrobial treatment safely removes 99.97% of airborne particles as small as 0.3 microns, including allergens, viruses, and cigarette smoke. Proven to capture the airborne flu virus. Carbon filter removes odors and captures large airborne particulates. Aera+™ Mode for allergy and cold/flu seasons. Also features AeraSmart Sensor and PlasmaTrue™ Technology. Ultra-quiet operation. 225.13 x 16.00 x 8.13 in. 18.10 lbs. AHAM, CARB and Energy Star Certified. UL Listed. 3 year limited warranty.