The AeraMax® 190 Air Purifier effectively purifies air in medium rooms 200-400 square feet. The AeraSmart™ Sensor monitors the air quality and automatically adjusts the fan speed to keep your air purified. In addition, the True HEPA filter with AeraSafe™ antimicrobial treatment safely removes 99.97% of airborne particles as small as 0.3 microns, including pollen, ragweed and other allergens, viruses, germs, dust mites, mold spores and cigarette smoke. Extremely effective at removing influenza and cold viruses from indoor air (based on independent testing). Carbon filter removes odors and captures large airborne particulates. Filter Change Indicators let you know when it is time to replace your True HEPA (#9287104) or Carbon filter (#9324104). The air purifier also includes the Aera+™ Mode for allergy and cold/flu seasons and features ultra quiet operation.