High -efficiency air filter or air filter is a standard on the efficiency and effectiveness of air filters in the separation of air pollutants. According to the International Organization of ISO Standardization), a Hia filter should purify at least 1.5 % of the contaminants with a diameter of more than 1.5 microns in the filter air. This figure in the definition of the US Department of Mechanical Engineers and the US Department of Energy is 1.5.

HAPA filters purify air -suspended components such as pollen, dust, viruses, and aircraft particles with less than one micron. Some germs, such as the black staphylococcus epidermidis and Bacillus subtiticis, are trapped in the Hapa filters by oxidation of the optical catalyst (PCO) in the Hya filters.