Note: I was curious what we were talking about this time last year, so I went into the archive and saw we were talking about farts!  I thought this post from last year was both informative and funny.  And since it’s still relevant, I figured I’d share it again. 

Question: I thought of an analogy today and I wonder what you think of it. If I fart indoors and I’m 6 ft away from someone, they will still smell it. If I fart outdoors and I am 6 ft away, they likely won’t. Could this be a helpful way to explain the dissipating effects of being outdoors as well as the risks indoors? Heck, I wouldn’t fart indoors even if I was 20 feet away, but I might risk farting outdoors (depending on the breeze of course) even if I was 3 feet away. The same thing can be said for COVID. (and a mask will, of course, help in any of the situations)

Answer: Your analogy made me laugh, thanks! And if people are confused about why outdoors is safer than indoors then I think your analogy is great! There are two questions that may arise in making this analogy though, and I raise the questions and answers because the internet raised them earlier in the pandemic:

1. If you can still smell a fart through your mask, what good is the mask doing for you?: As Trevor Makal, chemistry professor at University of Virginia explains that farts smell because they contain methanethiol, which is about 0.4nanometers (nm) in diameter. Meanwhile, most viruses range from about 20 to 400 nm — and SARS-CoV-2 is 60 to 140 nm in size. “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).” Most tight weave masks will block the virus, but because the odor molecule of a fart is so much smaller, the smell gets through. Masks== protect from virus, not from stink.
2. Can coronavirus be spread through farts?: No! Snopes did a factcheck on this one after online rumors were apparently flying and even Stephen Colbert did a bit (around minute 5:22). Basically, pants and other clothing keep the aerosol components of farts contained; it’s these aerosol components that carry wee bits of feces with them, which are the only components of farts that could be linked to disease; there’s evidence that the coronavirus can be found in feces, but as CDC writes, “it is unclear whether the virus found in feces may be capable of causing COVID-19. There has not been any confirmed report of the virus spreading from feces to a person.” Basically, as long as you wear pants when you fart and/or stay far away from other people when you fart, you will not spread any disease, including coronavirus. You’ll just spread some stink!