During the pneumonia epidemic of novel coronavirus infection, masks are more scarce, so N95 masks can be reused.
Although the filtration efficiency of N95 masks decreases over time, they can be reused if they are stored and used effectively, but there is no definitive conclusion on the best time to wear N95 masks.
Note that before wearing the N95 mask repeatedly, wash your hands according to the protocol and avoid touching the inside of the mask when wearing it. The mask should be replaced immediately if it is contaminated, wet, or broken, and the use time should be shortened in high-risk environments.