company news about What's the material of HEPA filter?

HEPA filters, or high-efficiency particulate air filters, are defined by how well they have been rated to filter particles, not by how they are made. To meet the HEPA standard, a filter is estimated to remove 99.97 percent of particles that are 0.3 microns (or micrometers) in size from the air that passes through them, though this means that particles smaller than 0.3 microns can escape the HEPA filter.

In practice, HEPA filters are made from a variety of materials, including “coarse glass fibers, coated animal hair, vegetable fibers, synthetic fibers (such as polyester or nylon), synthetic foams, metallic wools, or expanded metals and foils,” according to the EPA. These fibers are tangled together randomly and compressed into paper-like sheets. The sheets are pleated to increase the surface area that the air passes through, and mounted onto a frame made of cardboard, plastic, wood or metal. Manufacturers might add other elements to a HEPA filter, such as a pre-filter to screen out larger particles, activated carbon to help remove odors and gases or a chemical treatment to make particles stick to the fibers.