How about -- what's the max viral load one can sustain for it not to pass the 1st layer immune system? Is there really a 1st and 2nd layer? Can I resist it without getting antibodies? How much more effective is a KN95 / N95 mask in terms of viral load vs the others?
And why don't we have more high powered venting fans and permanent outside events and require building to open their windows or remove their walls in climates where that'd work?