N95 type mask is the certification level of the U.S. respirator, certified by the U.S. National Institute of Occupational Safety and Health. The mask in a standard environment such as a certain temperature, humidity, specified standard gas flow is 85L gas per minute through the volume, able to filter more than 95% of non-oil particles, that is, aerosol-type objects, so the name N95, that is, able to filter more than 95% of very small 0.3μm diameter non-oil particles. If you can filter more than 95% of the particles such as aerosols, this kind of mask may be less used and less seen, called N99 mask, is a better defense effect of a mask. N95 mask defense effectiveness is very good, basically can filter all droplets, in the usual prevention can be applied. It is not necessary to use a mask with a higher level of protection than N95, but you can use a medical surgical mask for protection, which has the same protection efficiency as N95 mask. N95 masks can protect for 1-2 days, but if used for medical purposes, they are also single-use masks and should be discarded promptly. Content source: Dr. You Lai