Non-woven mask: One is pure cotton absorbent gauze or knitted fabric with various non-woven fabrics in the middle; The other is directly sewn with non-woven fabrics. The filtration effect is good, but the air permeability is slightly poor. The latest variety is that the surface and back are made of non-woven fabrics with filter paper in the middle, which makes non-woven mask's filtering effect by going up one flight of stairs.
Gauze masks are made of sparse cotton cloth and are mainly used in working environments with low concentration of harmful gases and vapors. The filter box contains only adsorbent or sorbent.