This HEPA filter is effective against 99.99% of airborne pollutants and viruses, producing the cleanest home air possible. Its multi-filter system begins with a plasma generator that produces both positive and negative ions (most units only produce negative ions) to generate Hydroxyl (OH), which inactivates airborne particles and viruses by robbing them of hydrogen. Next, a washable anti-bacterial pre-filter catches larger airborne particles. Air is then passed through a HEPA filter that captures 99.97% of particles down to .3 microns, and a nano-silver mesh which neutralizes airborne bacteria. The final stage is a washable carbon filter that removes smoke and odors; most other carbon filters cannot be washed. This cleaner has a Clean Air Delivery Rate of 180 cubic feet per minute (CFM) for tobacco smoke and dust, and 190 CFM for pollen, rates which have been tested and certified by the Association of Home Appliance Manufacturers. Odor and dust sensors automatically adjust the fan speed as needed and alert you when filters need replacing. A light sensor activates a "quiet" mode at night. Rated to filter the air of a space up to 280' sq. Programmable remote included. 21 3/4" H x 16 1/4" W x 8 1/2" D. (17 lbs.)