Hmm. Based on what I read, particles smaller than 0.3 microns have a widely "wandering" path of travel through the mask fibers on account of Brownian motion. My understanding was that 0.3 micron particles are the size that the N95 mask is least effective at blocking. Smaller particles are blocked more effectively, not less, until you get down to a scale so small that you pretty well exclude live biological material.

Not my original source, but discusses the same thing: https://multimedia.3m.com/mws/media/376179O/nanotechnology-a...

This is to say, 95% filtration is the worst the mask will perform, with particles of any size, as it relates to coronavirus.