Read on Twitter
I just saw a post about "If a fart can make it through underwear and a pair of jeans, how can a mask made of cloth save you from covid? Asking for a friend..[sic]" Well, firstly, thank you for the question! As a scientist (specifically a chemist, I am absolutely qualified to 1/9
answer this question! Let& #39;s consider the size of the molecules that make up the stink smell in farts. We& #39;ll focus on one particular example, as the others are similarly sized (when compared to the size of a virus). Methanthiol (CH3SH), like a number of thiol (-SH) containing 2/9
molecules, smells! When you work with it enough (as I have), it smells like incredibly intense garlic; though many would just say it smells putrid. If you want everyone to hate you, walk through a hallway carrying an open container of thiol compounds. Ask my former student 3/9
and colleagues, they all remember that day! Well, CH3SH is a rather small molecule with a diameter around 4*10^-10 m (0.4 nm, about 1.6*10^-8 inches). By comparison, viruses typically range in diameter from about 20 nm up to about 400 nm (J. Biol. Phys., 2013, 39(2), 215), 4/9
with COVID-19 being around 60-140 nm (Cell. Mol. Immun., 2020, https://doi.org/10.1038/s41423-020-0407-x).">https://doi.org/10.1038/s... The difference in sizes of the COVID-19 virus and a common odorant in farts is 2-3 orders of magnitude (100–1000 times the diameter of the smaller methanethiol). An N95 mask is capable 5/9
of filtering 95% of a test aerosol containing average particle size of 300 nm (from the CDC: https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/).">https://blogs.cdc.gov/niosh-sci... Basically, an N95 mask has a tight weave pattern with multiple layers that serve as a barrier to larger structures (like viruses, or simply spittle). 6/9
While the benefits of a specific mask will depend on the fabric and construction of the mask (not to mention how it is worn), having some form of barrier between an infected individual and a healthy individual is far superior to open air allowing for the transfer of virus 7/9
(along with other matter) between those individuals. Lastly, to argue that “since I can smell a fart through a mask, there& #39;s no point in wearing a mask to protect me against viruses” is like securing a medieval castle with a gate to keep out invading horsemen, 8/9
but arguing that because roaches can still enter that there is no point in having a gate. Clearly you have not considered that the horseman is the greater threat. 9/9
Thanks to everyone who has been interacting with this thread! I realize I slipped up with one of my replies. The peeing/jeans picture is not mine. I& #39;m not sure of the source of that particular image that was shared by someone else as a reply. Sorry for any confusion!
