4 ms·
> They certainly don't help with PM2.5 The requirement for a mask to be called KN95 is that it must filter out 95% of PM2.5 particles. > AQ is like that, cons
by flaviut 4y ago
> They certainly don't help with PM2.5
The requirement for a mask to be called KN95 is that it must filter out 95% of PM2.5 particles.
> AQ is like that, constantly for a big fraction of the year. Ever been to China or Mexico City?
Honestly, I'm not sure why those people don't wear a mask year round. I'd expect the rationale to be cultural, "no one else is doing it", rather than logical.