Yep, it’s nothing more than a geometry problem. The holes in commonly-worn masks, including surgical masks, range from about 1,000 to 5,000 times larger than the Wuhan coronavirus. As you say, using a mask to prevent COVID is as absurd as trying to keep mosquitos out of your yard with a chain link fence. Even the vaunted N95 mask has been proven to have no effect on preventing transmission. Yet there are still many, even a few on here, who cling to a superstitious faith in masks. Keeping a rabbit’s foot with them would be just as effective.
How large is a CO2 moleucule?
This paper implies that masks trap them.
While true that Covid viruses are much smaller than holes in face masks, it is also true that much disease is spread from sneezing and coughing which spreads contaminated water vapor. The water vapor droplets are larger than mask holes so are mostly stopped on the mask’s exterior along with the germs. The viruses become inactive in about 3 days which is why I rotate 4 masks, using a different one each time I go out. My only exposure to the public is a food shopping trip every 3 or 4 days and 1 or 2 bank trips each month which my partner drives me to. So maybe 10 hours a month using a mask and never more than one hour at a time.
I am 84, thus not pregnant, a child or a youth. It is a real problem for people who might have to wear one all day for a job or other long time period. I also looked at research on social distancing. Droplets spread by sneezing or coughing have generally fallen below face level in 4 feet and below chest level at 6 feet. So I try to maintain some distance in public. Some people are real antisocial by not covering their mouth when sneezing or coughing, and they should stay home or mask in public if something causes them to do this frequently.
My partner gave me a respiratory illness from babysitting his grandson when his son a doctor begged him to babysit for 12 hours because he had used up all his sick leave (maybe RSV?). I was intermittently ill for 3 months and always wore my mask if I had to go out for food or money. I had no desire to spread my illness to others. So mask wearing should be a matter of common sense and courtesy, not rigid law.