At present, the common masks on the market can be divided into three types according to the mask making materials and manufacturing processes, including medical surgical masks, medical protective masks (N95 masks), and ordinary cotton yarn masks. Medical surgical masks generally have three layers, from the outside to the inside are a waterproof layer, a filter layer, and a comfort layer. The comfort layer is a layer of gauze, and medical surgical masks can block 70% of pathogens.
N95 masks commonly used in medical protective masks (N95 masks) are actually divided into two types, one is a bio-proof mask (blue-green), whose model is 1860 or 9132; one is a dust-proof mask (white), whose model is 8210 . Citizens should choose bio-protective medical protective masks when purchasing. N95 masks can block 95% of pathogens.
Cotton gauze masks may be made of cotton, gauze, wool, canvas, and velvet. Because the material itself is not dense enough to prevent infection, it can only block 36% of pathogenic bacteria.
Experts say that citizens should choose the first two masks. For the purpose of self-protection and reducing the risk of respiratory infections, the first two masks (that is, medical surgical masks and N95 masks) can be used.
If it is to go to general open-air public places without close contact with respiratory patients, it is sufficient to wear medical surgical masks without over-protection. However, if you come into contact with a patient suspected of having a respiratory infection, you need to wear a biologically-resistant N95 mask for effective protection.