Current N95 and other N95 equivalent masks such as the KF94 and the KN95 masks all utilize meltblown fibers that use a static method where an electrostatic charge is used to have particulates stick to the fibers.  As a characteristic of static, when these fibers are exposed to moisture, the filtering efficiency drops around 30%. 

 

Unlike the meltblown fibers, nanofibers filter through micro-pores that are formed from its physical properties and not static.  

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For this very reason, N95 masks, KF94 masks, and KN95 masks cannot be washed or sprayed for reuse because the contact with moisture reduces their ability to block particles from 95% or 94% to around 65%.