With the increase in the number of new coronavirus infection cases, people are becoming more and more aware of "wearing a mask", but what kind of mask to buy, how to wear a mask, and how to take off a mask? There is a lot of knowledge in this.
So many masks, how to choose?
Generally speaking, there are three common protective masks: protective masks, medical surgical masks and ordinary cotton gauze masks.
Protective masks (N95, KN95)
The N95 mask we often talk about is one of the nine anti-particulate masks certified by NIOSH (National Institute of Occupational Safety and Health). "N" means non-oily particle filtration, "95" means that the filtration efficiency is not less than 95%. KN95 is a mask that meets China's GB2626 mandatory national standard, similar to N95 (if the mask is only marked with "95% filtering bacteria", it does not count as an N95 mask). N95 masks play a vital protective role for front-line protection personnel and isolation personnel in epidemic areas. Because the virus does not exist alone in the air, but is spread by attaching to suspended particles in the air, such as droplets in the mouth. The droplet diameter is generally 1-5 microns. N95 and KN95 masks can isolate up to 95% of 0.075-micron particles, so they can effectively prevent the spread of the virus.
There are two types of commonly used N95 masks, one is the blue medically certified bio-repellent mask (1860/9132), and the other is the white ordinary dust mask (8210, etc.). Although it is said that the blue bio-repellent mask has better anti-bacterial effect, the white dust-proof mask can also block most of the bacteria and microorganisms. Both types of masks have anti-bacterial effects. Blue medical protective masks are currently in short supply, and are given priority for frontline personnel. Therefore, for most small partners, choosing white N95 masks is sufficient.
Medical surgical mask
Medical surgical masks generally have three layers. From the outside to the inside, there are a waterproof layer, a filter layer, and a comfort layer. The blue layer is the waterproof layer, and the white layer is the comfort layer. Therefore, it needs to be blue outwards and white inwards. Do not wear it backwards. Compared with N95 masks, medical surgical masks can only block 70% of the pathogenic bacteria, and the validity period is only about 4 hours, while N95 is usually 24-48 hours.
Ordinary cotton yarn mask
Ordinary cotton gauze masks are mostly made of cotton, gauze, wool, canvas, and velvet. The material itself is not dense enough, so most may only block about 36% of pathogenic bacteria. Of course, if there is really no way and stay away from the epidemic area, to prevent droplet infection, self-protection, and reduce the risk of infection, choosing a gauze mask with more than 9 layers is also an option, and the advantage is that it can be washed and used repeatedly.