Views:3 Author:Site Editor Publish Time: 2021-06-07 Origin:Site
The role of the N95 mask is to allow air to pass in and out to maintain human life needs (retaining cavities), and to block the entry of harmful viruses, bacteria and dust (make the cavities as small as possible to block objects of a specific scale). The basic principle is to make the size of the ventilation holes that maintain breathing smaller than the size of the virus spacecraft (droplet aerosol), thereby blocking these "alien" attacks.
Take the N95 mask as an example, it can block 95% of particles above 0.3 microns (300 nanometers). The size of the new coronavirus is 69-220 nanometers, just below the lower limit of the N95 mask. Therefore, simply comparing the sizes of the two, ordinary N95 masks really cannot prevent the virus from passing through. This may be the basis for an article saying that ordinary N95 masks "cannot protect against viruses" and are "useless". But don’t forget that the standard for blocking particles of medical N95 masks is the same as that of ordinary N95 masks. The only difference is that medical masks have the added function of preventing high-pressure liquid splashing. This situation mainly occurs in hospitals during surgery. , Vomiting and other special high-pressure jet conditions. Therefore, ordinary N95 masks are not anti-virus, and medical masks N95 are also ineffective.
As mentioned earlier, N95 masks mainly block the virus-carrying carrier-virus spacecraft-droplets or aerosols. It blocks the transport ship and also blocks the large force of the virus. It is not ruled out that some viruses become the fish that slip through the net. However, these stragglers may not reach the lower limit of infection concentration. Even if we break through the first line of defense on the surface of the human body and enter the body, our own immune system can deal with it. Therefore, N95 masks can greatly reduce our chances of being infected by viruses. The higher the protection level, the better the protection effect.
So what is the scale of the virus spacecraft-droplet? , Most of them are between 0.74-2.12 microns. The filter standard is greater than 0.3 microns for N95 masks. Therefore, ordinary N95 masks, as long as they are qualified products that meet the standards, can stop the attack of the new crown virus. Moreover, the blocking of external particles by masks is not only a matter of scale, but a comprehensive protection by multiple means.