The masks we can buy now should be divided into three categories: N95 (including KN95), medical masks and ordinary masks. The difference is as follows.

1, N95 (including KN95) mask

First of all, it is clear that N95 is the American standard and KN95 is the national standard. Its characteristic is that it can filter 95% of 0.3um particles, which can block the virus. Used for airborne diseases.

2, disposable surgical medical mask

Medical disposable masks are usually divided into three layers: the outer layer has a waterproof layer to prevent water droplets from entering the mask; The middle layer has a filter layer, which can block 90% of 5μm particles; The inner layer near the nose and mouth is used to absorb moisture.

3. Ordinary masks

Including old-fashioned cotton masks, PM2.5 activated carbon masks, and sponge masks used to keep warm in winter. They are useless to novel coronavirus! Usually, this kind of mask can only prevent smog, and it is thick, sultry and has poor sealing with the face.

The role of mask

The function of the mask is to isolate dust, sandstorm, virus, toxic and harmful gases and smells, including droplets, and it also has a good filtering effect on the air entering the lungs. You must wear a mask when working and living in a polluted environment. If you have respiratory infectious diseases, you can also wear a mask to prevent infection.