After the mask cover mouth, nose and chin some, constitute a medical mask and face seal space, by the suction force air through a mask when filtering harmful s

The haze weather is a state of air pollution, haze is to exceed the standard content of suspended particles in the atmosphere of the general formulation, especi

In modern society, serious pollution, air pollution that masks the rapid development of industry, we all know that dust masks can be bacteria or even anti-virus