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They say 90-95%. The thing is, to reach that you have to know how to wear one correctly! That means you have to be trained and fitted!

Basically, it’s not happening in the general public. Also, anyone that has warned a proper N95 mask, for any period of time, will tell you it’s not comfortable. Also, since COVID 19 has an animal reservoir, it’s everwhere, so you have to wear all the time.

When think about it, it doesn’t make sense.

As I understand it even the N95s are only 80% effective.

Not quite. It depends what you're trying to filter out, but an N95 by definition is at least 95% effective for particles 300 microns or larger. (N99 is 99% minimum, and Ps mean oil-resistant.) As you get smaller, the masks lose effectiveness for sure. Waay back in my posting history (year or so, so I'm not digging it out), I posted an older study on mask efficiency from before they got politicized. Properly sealed N95s are generally ~98% effective at the ~300micron size.

But one problem is that 2% - if there's viri present, and you're getting a 2% dose of 'em, you're still getting some, perhaps enough to infect you. And the longer you're there, the more you get - one minute with a 50% effective mask is "safer" than an hour with a 2% mask.

And this completely ignores the BIIIIG factors - most people aren't even wearing sealed N95s, they're using a torn tshirt or a scarf or bandanna or those crappy useless blue surgical masks (vape or smoke a cigarette with one - how much of the smoke goes around the edges of the mask? Usually 60-80% of it!). They aren't following proper decon procedures - no biohazard disposal, people touch all over it (the filter is full of whatever got filtered out!), they take em off and put em back on (HUGE NO-NO), they don't refresh (new sterile mask) every hour or so, they don't replace the mask when they get slightly wet (compromises filtration efficiency), and so on.

Even if the filter was 100% effective, how people use these makes them essentially 0% effective, if not the opposite and actually causing harm.