The main difference between N90 and N95 masks is the degree of protection. Where n means not suitable for oily particles, while 90 and 95 represent the protective ability of the mask. Different degrees of protection represent different protection and filtering capabilities of masks, i.e. different filtering capabilities against micro dust, bacteria and viruses.
N95 mask indicates that under the test conditions specified by NIOSH standard, the filter efficiency of the mask for non oily particles such as dust, acid mist, paint mist and microorganism reaches 95%, while that of N90 mask is 90%. Therefore, N95 mask has better protection ability than N90 mask.