HEPA is an acronym “high-efficiency particulate air (filter)”. This type of filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns. Filters, whether for an air purifier or other implementation, come with many benefits and claims.
All air cleaners need periodic cleaning and filter replacement to function properly. Always follow the manufacturer’s recommendations on maintenance and replacement.
What sets HEPA filters apart from the rest is their claims are more than just claims. In order to be called a HEPA filter, it has to be tested and approved. The Institute of Environmental Sciences and Technology dictates that a HEPA filter must trap 99.97% of particulates 0.3 microns or larger. This does not mean that the filter cannot trap particles smaller than 0.3 microns, because many HEPA filters can; it is simply the threshold that must be reached in order to carry the HEPA name.
How do HEPA filters work?
HEPA filters trap air contaminants in a complex web of fibers. Depending on the size of the air particle, this can happen in four different ways including inertial impaction, diffusion, interception, or sieving. Larger contaminants are trapped via inertial impaction and sieving. The particles either collide with the fibers and become trapped or are trapped while attempting to travel through the fibers. Medium-sized particles, as they move through the filter, are grabbed by the fibers via interception. Smaller particles are dissipated as they travel through the filter and eventually collide with fiber and are trapped.
