Before wearing the mask, after taking off the mask should be good hand hygiene. When wearing a mask, distinguish between the inside and outside of the mask and the top and bottom. Generally light-colored inside, dark-colored outside, with the nose bridge clip in the upper. Inside and outside, on the bottom do not wear the opposite, not to mention the two sides in turn to wear. When wearing a mask, the nose, mouth and jaw should be well covered. Put the thumb and index fingertips of both hands on the bridge of the nose, start from the middle position, press inward with your fingers and gradually move to both sides, shape the nose clip according to the shape of the bridge of the nose, so that the mask fits tightly on the face. When removing the mask, do not touch the outer side of the mask to avoid contamination of the hands. In the office, masks that need to be reused should be hung in a clean, dry and ventilated place after use.