A sanitary product used to filter air into the mouth and nose

Mask is a kind of sanitary product, which is generally used to filter the air entering the mouth and nose, so as to block harmful gases, smells, droplets, viruses and other substances, and is made of gauze or paper.
Masks have a certain filtering effect on the air entering the lungs. When respiratory infectious diseases are prevalent, and when working in dust and other polluted environment, wearing masks has a very good effect.
Masks can be divided into air filter masks and air supply masks