A perfect summer day is when the sun is shining, the breeze is blowing, the birds are singing, and the lawn mower is broken. - James Dent
Question #93230 posted on 07/16/2020 8:14 p.m.
Q:

Dear 100 Hour Board,

I came across a weird anecdotal story by someone who is anti-mask during the coronavirus pandemic. The gist of it was that they sprayed essential oils in the air and a grocery store employee wearing a mask could still smell it, so that was proof to them both that masks don't protect against coronavirus because the scent molecules are much larger than the coronavirus. I'm not on board with this at all but curious what should be said to refute the supposed science in this urban legend. I also don't know anything about how scents work and if smelling one while wearing a mask is any reflection on viral blocking capabilities. Help?

Thank you!

- The masked bandito

A:

Dear Masked Bandito,

I'm not an expert in this, by any stretch (I haven't even taken any Organic Chemistry classes), but I have a rough knowledge of how these things work and I thought I'd shed what little light I could on the matter (if I make any egregious errors, please let me know).

Now: you wanna see something gross?

(If you don't wanna see something gross then, uh...well I don't know how easy it's going to be to avoid seeing the picture directly following this text but you might want to try.)

Sneeze.jpg
(Source)

That would be an illustration of a sneeze, in case you couldn't guess. That is all of the little bits of fluid that rapidly exit your mouth when you sneeze. Very gross. Blech. Wear a freaking mask.

Now, think of the kind of mist that would be emitted by an essential oil sprayer. Obviously, I'm not doing a very scientific comparison, but to my mind I feel like most of the mist droplets exiting the sprayer would be smaller than those seen in the above picture. That's not to say that a sneeze can't produce a fine mist; we can see it in our sneeze picture wherever there's more of a cloud instead of clearly-defined drops.

This is relevant because the most common way of contracting the coronavirus is through contact with virus-carrying droplets produced by breathing, coughing, or sneezing. In most cases, the virus is not flying around willy-nilly on its own; it is being carried by moisture droplets, and these can be fairly reliably blocked by a face mask.

(I said this is true in most cases: recent research has indicated that, in certain situations, the virus can be airborne, meaning it travels through the air without aid of moisture. In this case, the virus could bypass a face mask, but again, you're much more likely to get sick if you come in contact with infected fluids.)

Now, from another angle: how sensitive is the human nose? In other words, how many scent particles do you need to inhale in order to actually detect a scent? I'm not very confident in my answer here, as most articles I found about nose sensitivity were talking about the range of different scents we can smell (around one trillion, apparently). The one article I found that talked about quantity came from a site that did not seem 100% reliable (though it also didn't appear 100% unreliable; I'd put it at maybe a 70% on the reliability scale). That article suggested that we can detect the smell of a skunk after inhaling only 0.000000000000071 ounces of the scent (that's 71 hundred-trillionths). The case in point is that we actually do not need to inhale very many scent particles in order to detect that scent, so if the masked grocery store employee could smell the oil, that doesn't mean that very much of it got through. Again, I'm no expert in these matters, but I believe that the amount of virus you come into contact with can affect the degree of your infection. In any case, if you asked me if I wanted to be exposed to a small number of viruses or a very large number, I'd take my chances with the small bunch.

But here's the deal: no one is claiming that wearing a mask is 100% effective against the coronavirus. No one is saying that we can eradicate the virus entirely by wearing a mask. Whether or not you contract the virus, unfortunately, is ultimately up to chance. HOWEVER, that's not to say that there is nothing we can do to improve our odds. We can lower our chance of contracting the virus by staying at home as much as possible. We can lower it by staying six feet apart from other people when we do venture outside of our homes. We can lower it even further by wearing masks in public so that, even if we can't always stay six feet apart from others, we are still somewhat protected.

Until a vaccine or some other preventative measure can be developed, there is an understanding that we can't entirely prevent people from getting sick. We can, though, take measures to make sure that as few people get sick as possible, and that we have enough resources to take care of those people who do contract the virus. And that's the whole point of social distancing, wearing a mask, etc. I know you know that already, I just felt like I needed to vent it out. Every day I hope that the people around me will take this all more seriously. Every day I'm disappointed.

-Frère Rubik

A:

Bandito,

Masks work better when worn by the infected person, right? By their logic, the fact you can't smell their stinky breath means it's working! Tell them that, and also call them a doo-doo head. 

Just kidding. Don't be mean. Tell them what Frère Rubik said. 

Babalugats

posted on 07/17/2020 12:15 a.m.
Nurse here (though I'm not going to claim professional expertise on this, as I do not manufacture or test masks, I just wear a lot of them),
Just want to third what Frere Rubik said and add a bit on the subject. As the good Frere said, the point of surgical/homemade masks is not to completely seal in/out viruses/smells - just to reduce how far you spray the virus.
N95 masks, on the other hand, are made to have a total seal and keep out the virus. To be used for medical purposes, you have to be fit tested, which is performed by donning an N95 and putting a giant bag over one's head, which is then sealed and injected with special perfumes. If you can smell them, then that particular brand and size of N95 isn't a fit, and you have to try again. Once you find a mask that fits - properly seals out these chemical smells - then you can safely use that, and only that, brand and size of N95. If you gain/lose much weight, you have to be refitted. You can see how this complicates the PPE shortages.
If you're curious about how N95s work, this video is pretty interesting (and short): https://www.youtube.com/watch?v=eAdanPfQdCA&t=2s

Thanks for doing your part to keep us all safer,
-C.S.
posted on 07/17/2020 12:15 a.m.
At the beginning of quarantine, I read a funny (but scientifically sound) response to the question "if a fart can make it through jeans, how can a cloth mask save you from coronavirus". Here is a link to the artcle.

https://www.dailymail.co.uk/sciencetech/article-8275855/Professor-answers-question-jeans-stop-fart-mask-prevent-coronavirus.html?ito=email_share_article-top