We know that there will always be a nose bridge wire on the mask, which is used to fix the mask on the bridge of the nose, but some nose lines are not metal, but also plastic.
If the general disposable mask does not have a nose bridge wire, it cannot fit the mask well on the face. The top and sides of the mask will leak out. Wearing it while keeping a distance from the crowd can also play a protective role. However, in close contact, the protective effect of a mask without a nose bridge wire will be greatly reduced, which greatly increases the risk of infection. As a medical surgical mask, if there is no nose bridge wire, it is unqualified.