At present, there is no clear conclusion on the optimal wearing time of N95 masks in foreign countries, including WHO, and China has not made relevant regulations on the use time of masks.
Some researchers studied the protective efficiency and wearing time of N95 medical respirator. The results showed that the filtration efficiency of N95 respirator remained above 95% and the respiratory resistance changed little after wearing it for 2 days.3 days filtration efficiency reduced to 94.7%.
The CDC advises that in the absence of a sufficient supply of masks, equipment may be considered for reuse as long as it is not visibly soiled or damaged (such as creases or tears).
