Meh...virus particles do not travel through the air by themselves, so what needs to be measured is the size of the moisture globules they travel on.
Sand will pass through a mesh screen, but wet sand will not.
Hey Mac, thanks for repeating the leftist nonsense. When you are wearing a thin piece of fabric over your mouth and you are coughing, sneezing, or just breathing all the covering does is act like a viral reservoir and acts like a sieve to reduce the size of the “moisture globules” so that they can travel further and also are spread more consistently with every breath that you take.
What you are spreading is unfounded nonsense thought up by your self appointed government overlords. There is absolutely ZERO clinical evidence that a thin piece of cloth worn over someone's mouth helps prevent an infected person from spreading this virus. There is not even much evidence that masks manufactured to capture dust particles do much if any good. But public policy where we are at does not dictate what type of covering must be worn and even encourages a single layer of T-shirt cotton, or handkerchief material.