HEPA filter (High Efficiency Particulate Air Filter) applies to any device capable of filtering. HEPA filters can capture at least 99.97% of particles with a diameter greater than or equal to 0.3 m. They can filter out impurities and particles in the air, such as viruses, respirable dust, mites eggs and excretions, mold, dust, allergens, pollen, bacteria, dust mites or cigarette smoke, asbestos, various toxic dusts and aerosols from the air, dander, allergens from the fur of dogs or cats.