You're right on the numbers, but the virus (assuming that it even exists) isn't air borne. Like SARS-CoV-1 (which was never isolated either), it stays in the air by being part of a water droplet, which usually is bigger than 0.3 microns. So an N95 could filter that. That being said, all the specs for masks are derived from testing on dummies under perfect conditions. The dummies don't touch or move their masks, or have exposed eyes and ears through which a virus can enter. In the real world, so many factors make wearing a mask an exercise in futility.