Hepa Filters

HEPA

HEPA is a type of pleated mechanical air filter. It is an acronym for "high-efficiency particulate air [filter]" (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm).

That micron size (0.3) is referred to by scientists as the MPPS, or the most penetrating particle size. Scientists have found that particles of that size evade air filters more than larger or smaller particles.

You can find HEPA filters in most air purifiers. These are small, portable units that may work for a single room. If you are considering buying a HEPA filter, find out how much air that the filter can clean. Be sure you buy one that is big enough for the room where you plan to use it.