Well there's also the issue of range, those 30% of particles might well have far less velocity. Which might be all that you need in a well ventilated area, or m

Well there's also the issue of range, those 30% of particles might well have far less velocity. Which might be all that you need in a well ventilated area, or might be a meaningless difference in a busy room. Frankly I don't know, and I don't mind admitting I don't know. What worries me greatly though is that at some point saying you didn't know was misconstrued as an attack on ideology. I mean if I had to guess I'd go for something blocking 99% of the viruses at least 70% of the time over something blocking 70% of the particles at least 99% of the time. Of course it depends, but one of those works to some extent at least 70% of the time, while for the other it is unclear. But really it depends. If we're talking about umbrellas those two scenarios result in you getting roughly equally wet, yet if we're talking about bullet proof shields I'd take my chances with the shield stopping most bullets at least some of the time over the one stopping only 2 out of 3 bullets.