Four-stage hospital-type filtration that effectively cleans air in small spaces. The Smart Sensor detects air quality and automatically adjusts the fan speed to keep your air purified. A 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 effective at capturing the airborne flu virus. Carbon filter removes odors. Certified asthma & allergy friendly™ by the Asthma and Allergy Foundation of America. The air purifier also includes the Aera+™ Mode for allergy and cold/flu seasons and features ultra-quiet operation. Fellowes® 90. Air Cleaner Machine Type: HEPA/Carbon; CADR: 68 (smoke); 65 (dust); 75 (pollen); Maximum Room Size (Square Footage): 100-200 sq ft; Maximum Room Size: 9 ft x 9 ft up to 18 ft x 18 ft.