Under normal circumstances, KN95 standard masks can be used for 3 days if there is no epidemic situation, but now it is more severe to go to the new type of pneumonia epidemic. The doctor’s recommendation is to replace it every 4 hours. If you go to a crowded place, it is appropriate 1-2 Replace every hour. If the KN95 mask is contaminated, such as in a crowded place or in an epidemic area, if the KN95 mask is sneezing or coughing from the other side, it is contaminated and needs to be replaced in time.
Medical KN95 masks can generally be used for 3 days, but in the current situation, it is recommended to replace them every 4 hours. It also depends on the surrounding environment. If you are walking in the community, KN95 masks can be worn multiple times without going far away. Just change one a day, but if you are going out to a crowded place, it is recommended to change it every 4-6 hours, and just 2 masks a day.