Gauze masks cannot effectively protect against the new coronavirus, so they are not recommended. At the same time, because cotton masks, sponge masks and activated carbon masks are mostly made of gauze, cotton, sponge and canvas, the material is not dense enough and the gaps are large, so they cannot effectively block the new coronavirus, so they are also not recommended. It is recommended that the general public use medical surgical masks, medical protective masks, medical care masks and industrial particulate protection masks such as N95 and KN95. In addition, going out less is also the key to prevent the virus, and the public should take care to avoid public places with heavy traffic.