HEPA filters are never mentioned as frequently as this year,due to the increase demand of masks and N95 respirator  during Coronavirus pandemic.

Formerly,HEPA filters are mostly used for industry,and you can find details at the main menu item “industry application for air filter”

At the begining of Covid-2019,volunteers sew mask for hospitals.But a cotton mask really do no help for virus.Then people konws about N95 and 3-ply masks has HEPA filters in.See what is HEPA filters at page HEPA filters and high efficency filters

Above is a picture tells the use of HEPA filters for capturing virus.The HEPA filters in masks are usually H13/H14,and the material are Melt blown cloth or PP