Wearing two masks together may be useful in blocking viruses, but wearing two masks together is not recommended. Wearing two masks can increase their ability to block viruses to a certain extent. Therefore, in some high-risk or high-risk areas, good protection can be achieved by wearing two masks. The protective effect of the mask mainly depends on the type of mask, as long as it is in line with the relevant production standards of medical surgical masks or N95 masks, and according to the requirements of wearing, a mask can achieve the desired protective effect. For viral infections, medical surgical masks and N95 masks are more effective. The key indicator of mask protection is airtightness, i.e. the fit and airtightness of the mask around the face. When you go out, you must pay attention not to go to crowded places, but also to wash your hands, open the windows more often to ventilate, and keep the indoor air fresh and circulating, and the temperature and humidity are appropriate.