I got into an argument on FB with a medical doctor who is also a personal friend. She spouted the general received wisdom & I counter argued -- not my usual mode. I usually try to respect the doctors as knowing more than I do, but in this case I don't think so. So here was the argument
Position of Dr
I think some people need to take a course in logic and logical fallacies. We need science, not intuition. N-95 masks (very tiny pores which can filter out viruses) protect the wearer, surgical masks (which viruses can pass through) decrease the transmission from an infected individual.
What I'm reading online is that hand washing is only about 20% effective in preventing transmission of colds and flu. I don't think it's going to be much better than that at preventing COVID-19 transmission. Also, what I'm reading online is that ordinary surgical masks have a range of protectiveness -- certainly not 95% like the N-95 masks, but still somewhat. I saw one estimate of 30-60%, which would be higher than hand washing. We're also seeing less spread of the virus in countries like Taiwan and Japan, where everyone is wearing masks. I'm not buying this business of the surgical masks having no protective effect. I think that's a distortion.
I saw an article online that one layer of a torn up tee shirt will block you from inhaling 50% of airborne virus. That's better than nothing.
If you walk through a grocery store, even if you keep 6 feet away, you're only two seconds away from breathing in what the next person has exhaled. The studies I'm seeing online are that COVID-19 remains airborne for between 1/2 hour and 3 hours. Certainly, it's still going to be there for 2 seconds. The surgical mask is better than nothing.
Also, the mask keeps you from touching your nose and mouth.
I TA-ed pre-med physics. I wasn't all that impressed that everyone understood basic Newtonian mechanics.
The reader may wish to read this article from Columbia University
It seems to me that, even if the mask only gives you 50% protection, that's better than nothing, when you're talking about a potentially fatal virus.