In addition to the filtering efficiency of the N95 mask, the closeness of the mask to the face is one of the important factors determining the effectiveness of the mask. Different types of masks have large differences in their suitability to the human face. Therefore, before using a mask, the suitability of the mask should be checked first. During the tightness test of the wearer's face, ensure that air can pass in and out through the mask when it is close to the edge of the face.
