A Media Air Cleaner or Media Air Purifier is a device which removes contaminants from the air. These devices are beneficial to allergy sufferers and asthmatics, and at reducing or eliminating second-hand tobacco smoke. Commercial grade Air Cleaners are manufactured as larger units that can be affixed to an HVAC unit found in commercial building or residential homes.
It uses a filter, filter based purification traps airborne particles by size exclusion. Air is forced through a filter and particles are physically captured by the filter, making the air that passes through it cleaner. HEPA (High-efficiency particulate air) filters remove at most 99.97% of 0.3-micrometer particles, and are more effective for particles which are larger.