I presume the comment about N95s not filtering smaller particles refers to the standard of filtering 95% of particles as small at 0.3 microns and viruses such as SARS-CoV-2 are much smaller than that. (0.1 micron) While I have no expertise as a virologist, it is widely explained that N95 masks stop smaller particles than 0.3 because of the way the particles move. That random movement makes it likely they will hit the fabric and stick. Additionally, an electrostatic charge attracts the smaller particles. In fact, the scientists say, the most difficult size particle for the masks to stop are those that are 0.3 microns. The masks actually do a better job of stopping microns smaller than that.