For disposable masks, it has a certain service life. Under normal circumstances, if you wear it continuously for more than 4 hours, you need to replace it with a new mask. If the mask is deformed, contaminated, or damaged, it needs to be replaced immediately. Otherwise, the protective effect of the mask will be affected, and the protective effect of the mask will be greatly weakened, so attention must be paid. Moreover, disposable masks cannot be cleaned and cannot be used again even after cleaning.
The outer layer of disposable masks tends to accumulate a lot of dust, bacteria and other dirt in the outside air, while the inner layer blocks the exhaled bacteria and saliva. Therefore, the two sides cannot be used alternately. If the disposable mask is moistened by exhaled heat or saliva, its function of blocking germs will be greatly reduced. Therefore, it is best to prepare a few more masks for replacement.