Rumor identification: Mask thickness is not equal to the protection effect. Rumor analysis: 1, medical surgical masks: thinner, generally have three layers, from the outside to the inside are waterproof layer, filter layer, comfort layer, comfort layer is a layer of gauze, medical surgical masks can block 70% of pathogenic bacteria. 2, medical protection mask (N95 mask): commonly used N95 mask is actually divided into two kinds, one is anti-biological mask (blue-green), model 1860 or 9132; one is dust mask (white), model 8210. in the purchase should choose anti-biological medical protection mask, N95 mask can block 95% of the pathogenic bacteria. 3, cotton gauze type mask: thicker, the material may be cotton, gauze, wool, canvas, etc., because the material itself is not dense enough, can not play the purpose of infection prevention, can only block 36% of the pathogenic bacteria, or even lower. Special Note: Although medical surgical masks and medical protective masks are thin to the touch, they have high filtration efficiency and can effectively block virus invasion. And the general cotton masks on the market, although thick but basically does not have the role of preventing infectious diseases.