@exsibilation @FinchTH I mean if any old cloth filtered well, we wouldn't have all these high tech filtration materials. It is probably possible to make a cloth mask that filters at 90% or so, but it requires a mix of very specific cloths, and still harder to breathe. Mostly pointless.
@exsibilation @FinchTH 我的意思是，如果任何旧布过滤得很好，我们就不会拥有所有这些高科技过滤材料。可能有可能制造出过滤率在 90% 左右的布口罩，但它需要混合非常特殊的布，而且仍然更难呼吸。大多是无意义的。