Sharp's new Air Purifiers use both passive as well as active technology to enhance air quality. Triple filtration is the passive technology that consists of a Pre-Filter, an Active Carbon Filter, and a True HEPA filter. The True HEPA and Active Carbon filters are replaceable and last up to 5 years. You can even clean the Active Carbon Filter and Pre-Filter! Plasmacluster¿ technology is the active technology that releases positive and negative ions into the air to deactivate impurities. With AHAM certified CADRs (Clean Air Delivery Rates), an elegant design and possibly the quietest air purifiers in the industry, Sharp provides a solution to your air quality needs!