Is it better to wear two masks?
Some people wear two masks. They wear a surgical mask inside and a KN95 outside. They think it is more effective. In fact, it is not. On the one hand, it will affect the air tightness of the mask and cannot breathe out the body well. On the other hand, the discharge of gas will hinder the body's exhalation and inhalation, increasing a certain resistance, thereby increasing the risk of infection, not only does not play a better protective effect, but also affects the human nasal cavity membrane.