Covid and Masks: It’s all about the droplets.
I want to talk about droplets and how masks protect us from them. You may ask, “What are droplets, and why are you bringing it up?” Droplets are the tiny drops of saliva and other secretions that come out of our mouths and noses by the thousands when we cough or sneeze-- or speak, for that matter. The droplets contain the viral particles that infect us. Yuck. The closer you are, the more likely you will inhale them, unless you and/or the other person are protected by a barrier, such as a mask.
So you have two choices to avoid infection, stay far away, or wear a mask, or both. Or seal yourself in a giant hamster ball, which has been done; well, until the police show up.
I just wanted to discuss a few factors to make sense of why we wear masks and socially distance, and why some situations are more dangerous than others. Overall, it is common sense, but it is easy to forget these things, even for me, a physician.
The size of the viral particles or droplets are important, and in this case, the smaller the deadlier. With a cough or sneeze, droplets emerge as large and small droplets. The large droplets travel anywhere from only 3 inches up to 6 feet, but mostly within 3 feet of the person producing them. The small droplets are lighter and easier to ride the air, and travel at least up to 6 feet, but in a violent cough or sneeze, or with singing or yelling, they can travel up to 30 feet, which is ten yards, especially if an air conditioner is blowing at your back. That’s a Covid 19 First Down.
If you read this and say “Well, that’s gross; I’m definitely wearing a mask,” you do not need to read further if you don’t want to. But if you are a geek like me, I want to go a little further into droplet science.
Our likelihood of significant exposure and infection from a virus depends on one main factor: the concentration of viral particles at the time of exposure.
We are more likely to be infected when we encounter a large amount of droplets all at once than we would by just a few droplets. Although, theoretically, it only takes a few particles to infect a person, it really takes a large concentration of at least two- or three-thousand to infect someone. The concentration of particles depends on several factors: the sheer volume of secretions that are coughed or sneezed; the size of the secretion droplets, the concentration of viral particles per droplet, and the velocity at which they come out.
All of those factors are then mostly influenced by the distance of the particle source to their victim. The greater the distance, the greater the chance for the particles to fan out (dissipate) and drop toward the ground, away from the face, as the droplets travel. Thank goodness for gravity and wind resistance.
So I hope it then makes sense to say that staying at least 6 feet apart diminishes the risk of getting enough particles to get sick; and that avoiding being around groups of people, especially at least more than 10 people in one room, diminishes the volume and concentration of particles that are present at one time. I also hope it makes sense to cover your nose with a mask. I don’t think people always understand that respirations and droplets still go through the nose and not just through the mouth. After-all we swab the nose to test for Covid 19. No one, I hope, would wear only half of a bullet-proof vest.
So the question is whether wearing masks is effective or not. Honestly, we, the medical community or society, may not know with certainty until we look back in a year or two at the data. But for now, I have to believe that masks work. They stop the flow of particles from the infected person. Some particles still come out, especially within the first 1-2 feet from the person, but not in the same numbers, velocity, or distance as without a mask. If people around that person are also wearing masks, then the particles have a much less chance of getting into the noses and mouths of those people. There would be a double barrier.
To look at it another way, if you saw a bunch of kids playing dodge ball, and it’s a melee, hitting each other like at a trampoline park, you can see easily how a large number of particles, the dodge balls, behave in a small space, with multiple opportunities to hit someone. But if the kids spread out, you have a better chance of avoiding being hit. If you then put a fence (mask) between them and you, or, better yet two fences, then you are better protected from being hit.
So in light of the above information, I recommend the following to avoid getting Covid 19 or the flu, or any illness:
1. Stay at least 6 feet away from others that are outside of your immediate household.
2. Stay up to 30 feet away from people who are coughing, sneezing, yelling (sporting/political events), or singing (church, concerts, or kids making another Tik-Tok video).
3. Avoid groups larger than 10 people. I would personally avoid more than 5 or 6, but that’s just me.
4. Never assume that someone will not have Covid just because you know that person well or are related to someone outside of your immediate household. (“I’m safe with them. They’re good people.”) Viruses do not discriminate, so still keep social distance and wear masks around friends and family that don’t live in your home.
5. Wear your mask, and wear a good mask; one that stops tiny particles.
6. Wear your mask when going into someone’s home.
I hope this article has helped you understand the recommendations to wear a mask. Stay safe and remember to wash your hands and use hand sanitizer. And wear your mask.
Carey Roach, MD is Board Certified in both Adult Internal Medicine and Pediatrics-Combined. He practices primary care medicine at the Barg Family Clinic in Little Rock, Arkansas. His views are his alone, although based on research and experience, but do not necessarily reflect the views of the management and staff of the Barg Family Clinic.
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