N95 masks and how they work
In: Technology
N means it’s Not resistant to oil. 95 means it should, properly used, filter 95% of particles 0.3 μm or larger.
[NIOSH air filtration rating](https://en.wikipedia.org/wiki/NIOSH_air_filtration_rating)
It’s the same principle as a coffee filter, you have the layers in the mask itself that are very fine as to catch anything in the air that passes through it like dust, harmful bacteria, fine moisture droplets that may harbour virus particles, harmful chemicals from various sprays etc. This prevents said things from entering the respiratory system, hence protecting the wearer.
What differs these say from say generic surgical masks is they are generally designed to make a close ‘seal’ with the face of the wearer and has much better filtration quality as well as providing much better protection to the wearer. A generic looser surgical mask offers little protection to a wearer from outside contaminants and it used usually for the reverse purpose, stopping someone from distributing potentiontial contaminants into a sterile enviroment or to other people.
Filters work not by sifting out particles larger than the spaces between fibers, but by stirring up air so that particles collide with, and stick to, the filter media. The holes are larger than the particles being captured so that air goes through more easily. The key for making an effective filter is to have as many very thin fibers as possible that are sticky to the particles you want to capture.
N95 masks are optimized for water-based droplets, so the stickyness of the fibers applies to water-based particles, like the droplets that viruses may be suspended in.
Latest Answers