How to distinguish the front and back of a disposable mask
Many people may think that the positive and negative sides are the same, as long as Dai Yanshi is done. In fact, this is not the case. The function of the front and back of the mask is different. Many masks use a three-layer design type, in which the filter layer for filtering bacteria is located in the middle, the outer layer is a waterproof layer, and the inside is a water-absorbing layer. If it is worn backwards, the water-absorbing layer will become a waterproof layer, and the waterproof layer will become a water-absorbing layer, which will cause the saliva to adhere to the surface of the mask, and the more it accumulates, the more the mask may get wet and the mask will lose its filtering function.
Judge by color
Generally, we see a blue medical surgical mask, the blue side is the outside, and the light-colored (white) side is the inside (attached to the face). There are also pink and black, which can also be judged according to this principle.
Judging by printing
If the logo or brand name is printed on the mask, it is easy to judge that the embossment of the logo or brand name is usually printed on the outside, and then you can know which side is outside by looking at whether the word is positive.
Judging by the direction of the fold
The direction down is outside.