HEPA Filters

originally called high-efficiency particulate absorbed but also sometimes called high-efficiency particulate arresting or high-efficiency particulate Resistance, is a type of air filter. Filters meeting the HEPA standard have many applications, including use in clean rooms for IC fabrication, medical facilities, automobiles, aircraft and homes. The filter must satisfy certain standards of efficiency

Varying standards define what qualifies as a HEPA filter. The two most common standards require that an air filter must remove (from the air that passes through) 99.95% (European Standard)