The quality of the protective mask is directly determined by the material
The most popular masks sold online are mainly divided into two types, one is the US N standard mask, and the other is a mask with activated carbon. Some businesses have also identified the "PM2.5-proof" category in N-standard masks, which looks very tempting. So what is the basis of the protection of these hot-selling masks, is it "reliable to prevent PM2.5"?
Liu Liying, a researcher at the Beijing Institute of Labor and Shelter Science, hinted that the protective effect of masks is directly related to the materials used. Because the fundamentals of the masks are not different, the goal is to block the human respiratory tract from the outside air. Just according to the different goals, the tailoring design of the masks and the materials used are different.
The materials used by the American N standard masks are different. Some manufacturers also use polypropylene spunbond non-woven fabric as the front and back protective layer, and polypropylene ultra-fine melt-blown non-woven fabric as the middle layer. Some also use electrostatic filter cotton as an intermediate layer. These materials are relatively strong in filtering ability. During the N standard test, 0.3 micron particles are used, which is a very high standard in masks.
"Preventable PM2.5" is not scientifically sufficient
However, some activated carbon medical masks are filled with activated carbon. The primary effect is to block the taste and filter the suspended particles. Therefore, in foggy days, masks filled with activated carbon are not recommended. The surgical masks that have been popular before only filter the exhaled air to prevent patients from being infected. It has limited ability to protect itself and does not recommend it. So as far as protection is concerned, industrial masks are better. However, there is no necessary basis for such claims as "preventing PM2.5". At first, these industrial-grade masks have no scientific test data on the particles detected by PM2.5. Second, these The particles used in industrial-grade mask tests are all 0.3 micrometers, and no one uses exceptional particles, but there are differences in the results of isolation. So it is impossible to say which one will prevent PM2.5. Which one is unpredictable. So this kind of statement is more a means of selling by merchants, and lacks sufficient scientific basis. "