What is the protective effect of kn95 / N95 respirator with breathing valve?
kn95 / N95 masks also have breathing valve and no breathing valve. For respirators, the results of air permeability and filtration efficiency are always a pair of contradictions. If the filtration effect is good, you will often feel suffocated. The breathing valve is designed to relieve suffocation.
The exhalation valve and the inspiratory valve are mechanical switches. They close when inhaled and open when exhaled. The air passes through the filter "screen" once. When exhaled, the valve opens to reduce the sense of resistance. The problem is that people don't know if the mechanical switch will break down suddenly when they wear it, or if it will be stuck by small particles, so that the air carriers who don't pass through the filter layer can take advantage of harmful particles. Therefore, medical masks have no breathing valve. At the same time, we also call on the general public to choose kn95 / N95 mask or medical surgical mask without breathing valve as much as possible during the anti epidemic period, especially when the surrounding environment is relatively poor.