Disposable masks are not medical masks, disposable masks are mainly made of two layers of non-woven fabrics, while medical masks have the role of filtering bacteria and particulate matter, consisting of three layers, two layers of fiber non-woven fabrics, the middle sandwich layer plays a role in filtering bacteria. Its effect is not the same, medical masks in the normal air flow, for aerosol filtration efficiency of not less than 95%, generally in line with the N95 and above grade, able to block airborne diameter <5μm infectious agents, or close contact with the infectious agents transmitted by droplets, and disposable masks do not have such a protective function. But note that medical masks are valid, generally valid for three years, more than the expiration date of the effect of filtering bacteria will be greatly reduced.