Original title: Medical surgical mask, N95, KN95 mask, 3m mask, a little dizzy What is a medical surgical mask? What are N95 and KN95 masks? What is a 3m mask? I can't tell the difference clearly. The surgical mask is a mask worn by medical staff at work, mainly used in medical outpatient, laboratory, operating room and other high-demand medical environment, with relatively high safety factor...