N95 Mask is actually respirator (respirator), breathing apparatus is a kind of respiratory protective equipment, in design compared with average masks joint face more closely, can very effectively filtering particulates in the air. N stands for Not resistant to oil, which can be used to protect non-oily suspended particles. 95 means filtration efficiency greater than or equal to 95%, indicating that after careful testing, the respirator can block at least 95% of very small (0.3-micron level) test particles.
From the design, if according to the wearer's own protection ability priority ranking (from high to low): N95 mask > surgical mask > ordinary surgical mask > ordinary cotton mask.
If worn correctly, the N95's filtration capacity is superior to that of regular and surgical masks. However, even if the wearer fits the bill perfectly, the risk of infection or death is not 100% eliminated.
In all, KN95 is one of the levels specified in Chinese standard gb2626-2006, N95 is one of the levels specified in the US standard 42 CFR 84. The technical requirements and test methods of the two levels are basically the same. The filtration efficiency is 95% under corresponding standards.