Unfortunately, I still have questions about what exactly your dean is referring to. If he was talking about the surgical/procedure masks that you see many people wearing on TV, then I would totally agree with his statement which is why I didn't really say anything about it the first time without more information. But, from that quote, it sort of seems like he is referring to N95's, in which case, I guess I take issue with the statement that they provide NO protection at all. It sounds like he's comparing an N95 to someone trying to use a bridal veil as respiratory protection against the flu.

But, again, context makes all the difference. For example, since an N95, by definition, lets 5% of the test aerosol through, some may consider that result to be the same as being useless since 5% may be enough to infect someone. <shrug> Not to be argumentative. I'm genuinely interested in the logic of what he's saying since on its face, it seems counter to everything things I've heard/read.

The point about the viral shape inside the droplet is interesting, although I have never heard any mention of that ever being an issue with filtration. If the droplet itself is much bigger than the individual virus particles, how the virus is folded doesn't seem like it would affect the shape or characteristics of the droplet itself. That's another potentially interesting piece to this puzzle.