Views:2 Author:Site Editor Publish Time: 2021-08-02 Origin:Site
Since the outbreak of the novel coronavirus-infected pneumonia, masks have become a scarce item that has been snapped up, especially N95 masks, which have become the most sought-after protective equipment. "You must wear a mask when you go out, and you must wear N95 masks" seems to have become the consensus of many people. Do you know how N95 masks protect against the new coronavirus?
First of all, we must popularize science about the particle size in the real world. The particle size of the general virus bacteria is between 0.3-1.1μm, while the particle size of the new coronavirus is between 0.06-0.22μm. Next, let's take a look at the principle of N95 mask blocking particles:
The principles of N95 masks to block particles are as follows:
Settling effect: Large particles settle on the filter fiber by themselves under the action of gravity.
Inertial impact: Due to the large inertia, large particles cannot follow the airflow to bypass the filter fiber, and hit the filter fiber to be filtered.
Interception effect: When the medium and large particles pass through the filter fiber, they are intercepted by the fiber because of its too large radius.
Diffusion: Small particles are affected by the thermal motion of molecules and present the trajectory of Brownian motion, causing them to deviate from the direction of the airflow and "hit" the fibers.
Electrostatic attraction: If the filtered fiber has a certain amount of static electricity, the particles in the airflow will be easily attracted by the static electricity and be filtered out.
Of course, the above five mechanisms work comprehensively to protect particles of various sizes as a whole. Moreover, once the particles come into contact with the fibers and are blocked, it is difficult for them to escape due to the influence of molecular forces and accumulate little by little on the mask.
Although the particle diameter of the new coronavirus is only between 0.06-0.22 µm, in fact the spread of the new coronavirus mainly relies on droplets and droplet nuclei as carriers (the diameter of droplets is generally greater than 5 µm, while droplet nuclei are less than or equal to 5 µm. , Generally greater than 1µm), floating aimlessly in the air, so N95 masks are also sufficient for blocking.