It is best to change the KN95 mask every four hours.If the face mask is contaminated,it should be replaced in time.
Ordinary people can wear it for a few days.If the face mask is not sufficient,as long as the kn95 mask is not damaged,no pollution,or patients who have not been in contact with infectious diseases,they can wear it repeatedly.If you have chronic respiratory disease,heart disease or other diseases with symptoms of dyspnea, you can use the kn95 mask with a breathing valve,so that you can breathe easier.Healthy people can wear kn95 face mask without exhalation valve,or economic disposable surgical face mask.
