@flowermusickids @kprather88 @CDCgov Depends on the mask. CDC measured some 3-layer cloth masks at around 30-40% I think. Obviously not great, and worse if not worn properly, and some aren't even 3 layer or worse material.
It is probably possible to construct a cloth mask that is 90% or better, but most aren't.
@flowermusickids@kprather88@CDCgov取决于面具。CDC对一些三层布口罩进行了测量，我认为大约30-40%。显然不是很好，如果穿得不好会更糟，有些甚至不是三层或更糟的材料。
制作一个90%或更好的布面面具是可能的，但大多数都不是。