How much do you know about KN95 masks?

1. What is a KN95 mask? KN95 is a Chinese standard mask. It is a type of mask with particulate filtering efficiency in our country. Because the new coronavirus is mainly transmitted through droplets, N95 means that it can filter 95% of the particulate matter in the air. The filtering ability of KN95 is better than that of ordinary masks and medical masks. If ranked according to the priority of the wearer's own protective function, the KN95 mask has the highest protective ability. 

2. The specific structure of KN95 masks Medical masks and protective masks are non-woven materials, composed of directional or random fibers, usually multi-layer structure, mainly composed of three layers, usually called SMS structure. At present, the highest number of layers in China is 5 layers, namely SMMMS, KN95 masks with higher protection level are 5 layers, 2 layers of meltblown cloth + 3 layers of non-woven fabrics, which can filter more than 95% of fine particles. 

3. How long can KN95 masks be used for? Compared with other types of masks, the price of KN95 masks is relatively high. Many friends have questions, can KN95 masks be reused? Of course, no problem. Some researchers have conducted relevant studies on the protection efficiency and wearing time of KN95 masks. The results show that: KN95 masks are worn for 2 days, the filtration efficiency remains above 95%, and the breathing resistance changes little. After 3 days, the filtration efficiency dropped to 94.7%. The application time of KN95 will vary according to different environments. For example, in the case of direct contact with bacteria and viruses, it usually lasts 6 to 8 hours, and no more than 8 hours. If used for general protection, the mask should be discarded when it comes into contact with blood or droplets. If the mask is damaged, it should be discarded. It should be discarded when breathing resistance increases. If this is not the case, the general guideline is to use two per week, or five working days if the maximum is one. 

4. Precautions for wearing KN95 masks 1. Wash your hands before wearing the mask, or avoid touching the inside of the mask while wearing the mask to reduce the possibility of mask contamination. 2. Distinguish the inside, outside, top and bottom of the mask; the printed side of the KN95 mask is facing out; one end of the metal strip/sponge strip is above. 3. Do not squeeze masks with your hands, including KN95 masks, which isolate viruses on the surface of the mask. If you squeeze the mask with your hands, there is still a chance of being infected. 4. Make sure that the mask fits tightly to the face. The simple test is: After putting on the mask, exhale forcefully to prevent air from leaking from the edge of the mask.