For your health, it is recommended to choose KN100 grade dust mask. It can provide more than 99.97% protection against ultra-fine dust.
Standard masks should meet the following requirements:
1, certified by the national standard.
2, the mask has three levels of KN100, KN95, KN90, of which KN100 has the highest protection rate.
3, masks according to the national standard size.
4, breathing smoothly.