The N series and KN series of masks

The N series of masks are American standards, the KN series are Chinese standards, the FFP series are European standards, and the KF series KN95 respirator manufacturers are Korean standards. The following number refers to the protection capacity, the greater the protection level, the higher. The diameter of water molecules in the presence of gas is about 0.4nm, and the overall particle diameter of the coronavirus is about 60-400nm. The cover cannot pass through particles with larger diameters, so it can block the virus. 95 refers to the efficiency of filtering such particulate matter up to 95%. The 90 series does not have the protection level of the 95, but it can resist more than 90% of the particles. In the FFP series, 2 basically corresponds to 95, and 3 has a higher filtration efficiency, reaching 99%.