The difference between masks is that the manufacturing process of masks is not complicated. If carefully divided, there are cotton masks, non-woven mask, polymer masks, activated carbon powder filter masks and activated carbon fiber felt pad masks. We usually use cotton masks, which can be bought in most supermarkets, including disposable masks.
Disposable masks The protective ability of disposable masks is of course the lowest. Although disposable masks can filter more than 95% of bacteria, they are not airtight. You can try to catch water with a disposable mask, and the water will soon seep down. So you can't prevent viruses, you can only block large particles of dust and so on.
Medical surgical masks Medical surgical masks can block particles larger than 4 microns in diameter, and there are mainly three layers (of course, most other masks are also three layers), which are waterproof layer, filter layer and comfort layer from outside to inside. This kind of mask has better air tightness and penetration resistance. In this epidemic, this kind of mask is the most cost-effective mask.
Medical protective masks This kind of masks have the highest level of safety protection, such as N95 masks, which have become "network celebrity products". N95 shows that under the test conditions specified by NIOSH standard, the filtering efficiency of mask filter material for non-oily particles reaches 95%. Of course, 95% is not an average, but a minimum.
The US Department of Labor has recommended the use of N95 masks to prevent air-borne diseases such as influenza and tuberculosis. N95 mask can also prevent virus, but no matter which mask can not be used for a long time, it should be replaced every few hours.
How do masks prevent viruses? For viruses, droplet transmission is the main route, and viruses enter the body through dust attached to the air. So in theory, as long as we stop the dust from attaching to the virus, we can definitely stop the virus. In addition, as mentioned above, only medical masks can block particles with a diameter greater than 4 microns. Therefore, the mask is the most economical anti-virus way at present, but it is also limited to outdoor use. Staying at home is the safest way to protect.
Masks can not only prevent viruses brought by others, but also prevent them from being transmitted to others if flu symptoms appear. In fact, the mask is a simple protective cover, which has a similar effect of slight isolation. Therefore, wearing a mask is a very simple and effective way for the health of yourself and others.
Air, like water flow, will flow to the place with low resistance first. For the mask, if it doesn't fit the face, the virus in the air will leak in from the gap between the mask and the face. On the other hand, if a person wearing a mask sneezes, the same thing will happen, and the virus will leak into the air. Even if you wear the mask of the best material and don't wear it correctly, it won't have any protective effect.