The design principle of N95 mask

The design principle of N95 mask. That is, the middle layer of melt blown nonwoven fabric is wrapped with inner and outer layer of nonwoven fabric, and the upper, lower, left, and right sides are thermally melted or sewn to close the edges. The middle layer of the 3M mask uses high-efficiency electrostatic filter cotton technology. The N95 mask relies on the static electricity generated by the non-woven fabric to absorb dust and droplets to achieve the filtering effect. If the mask is wetted by exhalation, the mask will lose its protective effect. In order to achieve the most effective protection, it is recommended to place a small piece of napkin in the mask. Try not to talk while wearing.

Viruses cannot be spread through the air. Viruses need to be spread by droplets. This is the most basic common sense. Droplets containing a large number of new coronaviruses are discharged into the environment through the mouth and nose when the patient inhales, exhales, sneezes, coughs, and gasps (asthma). Large droplets can fly 3 meters and finally fall to the ground. Small droplets can be suspended in the air for a short period of time, it can spread for 50 meters downwind and pollute the surrounding air. Influenza viruses with weak environmental resistance are transmitted in this way. Such transmission is more likely to occur in some crowded public places such as stations, schools, temporary work sheds, and prisons. In Hong Kong, there are cases of transmission between adjacent high-levels, so droplet transmission can involve contacts around pathogen carriers.