HEPA

Used in vacuums and air purifiers, HEPA filters are highly effective at blocking particles as small as 0.3 microns (a micron is 0.0004 inches), which can irritate airways or cause an allergic reaction. Equipment must be built to accommodate HEPA filters. They cannot be installed on non-HEPA vacuums, air purifiers and air conditioners, as air does not flow easily through them and can cause motors to burn out.