Strictly speaking, it is not a N95 mask, but a medical protective mask. KN95 is a mask produced according to industry standards in China, and its protective effect is basically the same as that of N95 mask, except that it has no sterilization treatment and blood spatter prevention function. In terms of protective effect, three-dimensional medical protective masks (N95 masks) and KN95 masks are better than plane masks.
In China, the national standard for medical protective masks is GB 19083, the standard for KN95 is GB2626, and the standard for medical surgical masks is YY0469. What standards do they follow for masks? The publicity of the merchants and the steel seal on the mask cannot be used as a criterion for judging.
Test method for tightness of n95 mask
Positive pressure test: cover the mask lightly with both hands and exhale forcefully. If the air overflows from the edge of the mask, it means that it is not properly worn, and the metal strips on the headband and nose bridge must be readjusted.
Negative pressure test: cover the mask lightly with both hands and inhale hard. The center of the mask will sink. If air enters from the edge of the mask, it will be improperly worn, and the metal strips of the headband and nose bridge must be readjusted. It is important to note that the side with the metal strip should be inward.