kN95 mask can isolate smaller particles, and fit tighter to the face, it is not easy to leak air from the periphery, and the filtration efficiency of particulate matter can reach 95% under standard conditions.
The kn95 mask is not a disposable mask. In this special case (resource shortage), it can be reused. But there are conditions:
However, masks cannot be reused if people go to the hospital, come into contact with an infected person, or are suspected to be infected.