First of all, we will make a classification of the types of commonly used masks. There are three types of non-woven fabric masks, and each type is used in a different place.
The first is a two-layer mask. Generally, the two-layer mask is mainly used in food processing plants. There is no filter meltblown cloth in the middle, but two pieces of non-woven cloth are sewn together. Its main function is to prevent the substances in the mouth from entering into the food, such as saliva, slurries, colds, etc. in general, its weight is about 45g.
The second is a three-layer mask. The sandwich is a piece of filter melt spray cloth, which is suitable for medical structure, outdoor, dust factory and other places. Its composition is double-layer non-woven fabric + a middle layer of filter melt blown cloth, which should be mentioned here.
The third is a disposable four layer active carbon mask, which adds a layer of active carbon paper on the premise of the original three inner layers of non-woven filter paper, better improving the ability of filtering dust bacteria. That is to say, the gray and black masks you see. However, it's enough to wear a three-layer mask outdoors. Of course, it's OK to wear a four-layer mask.
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