I bought a mask recently, the grade is kn95. Can this level prevent smog? What level is good?

Kn95 can prevent smog. Kn95 is very good. When the concentration of PM2.5 in the environment is about 350μg/m3, the decline rate of PM2.5 exceeds 84% after actually wearing KN95 mask.

After wearing KN90 mask, the decline rate of PM2.5 was 8 1.5%. Wearing ordinary disposable non-woven mask has no effect on reducing PM2.5, and the results suggest that wearing an anti-particle mask is effective in foggy days. After the sampling port was covered with a mask, the reduction rate of PM2.5 by KN95 mask was more than 9 1%, and that by ordinary disposable non-woven mask was 45.5%.

Extended data

Wear a smog mask correctly.

First of all, be sure to wash your hands before wearing a mask and before and after taking it off; The color face of the mask is outward, and the side with metal sheet is upward; Fasten the rope to fix the mask, or wrap a rubber band around the ear to make the mask close to the face; The mask should completely cover the nose, mouth and chin; Press the metal plate on the mask tightly along both sides of the bridge of the nose to make the mask close to the face.

Avoid touching after wearing a mask; If you must touch the mask, wash your hands thoroughly before and after contact. Secondly, every time you put on a mask, you must check the air tightness. The mask should be close to the face to play a filtering role.

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