KN90 masks can protect against viruses, KN90 masks are anti-particle masks. It can effectively filter not less than 90% of non-oil particles outside the body, and has a good barrier effect on airborne droplets, bacteria or viruses, but the protection ability is weaker compared to KN95 masks. The general population can play a good role in isolating viruses, and for people working in hospitals and epidemic prevention departments or quarantine departments, etc. it is recommended to wear and use KN95 masks. If the mask is dirty, broken, deformed and aging, it is recommended to replace it in time. At the same time, when the mask is not in use, it is recommended to be placed in a cool, dry and ventilated environment to extend the service life of the mask.