NSI Chairman’s Corner May 26, 2020
It’s 4 am and I am thinking about….
A COVID-19 PSA
Hopefully by the time you read this you will yawn and think “nothing new here,” which will mean that the Public Service announcement of how to minimize the second wave of COVID spread will have happened. As of this writing it has not, so I have been doing my part to try to get the message out in the wild world of media and politics.
I have seen some commentary about loud conversation (in bars) resulting in expelled particulates travelling up to 5x further than the 6 ft guidance everyone has memorized. But I haven’t seen any reporting that brings this down to the basic physics: the more an infected person is pushing air out, the further they will spread the virus. Get a number of infected people really exercising their diaphragms without wearing masks, even in a very large confined space (church, gym, basketball arena), and everyone will breath in some of their virus laden droplets.
Tells me we are making mistakes in what is being re-opened and that doing something like having people sit 6 ft apart in church is not going to stop the spread.
COVID, we are all pretty sure, is spread much more by air than by touch. So, understanding the physics of aerosol spread is critical. The general 6 ft separation for social distancing has very little applicability for anything other than people in a very large, still air space who are quiet or at most talking softly. Because of this, he “6 ft rule” we have all had beaten into our brains has only resulted in creating a completely false sense of security
I was thinking the other day about the number of Churches that became hot spots and why that would be. Came to the conclusion the primary culprit is not fixed by 6 ft social distancing.
If you think of the lung like an old-style bulb perfume atomizer, with a small squeeze you get a little, contained, spritz. Think of this as how you squeeze your lungs for normal breathing. Squeeze more, you get some scatter. This is speaking normally. Squeeze hard and you get spray that fills the room with perfume scent. This is shouting, preaching and, drumroll, singing.
My conclusion is the biggest cause of church infections is singing. Like the perfume atomizer, you squeeze hard and that spray will fill a room with scent. The atomized particles take a long, long time to settle. Of course, the perfume molecules are smaller than the COVID virus, so it won’t have the airborne time of perfume (a week or more in a confined room!). But we also know that convection in a room will keep a micro-particle aloft for hours (think dust particles you see in the sunshine coming through a window.)
Any time you are really pushing air out of your lungs: singing, shouting, huffing and puffing from exercise; you will fill a room with atomized particles from your lungs. The more an infected person is pushing out air (squeezing the atomizer ball) the farther and longer the virus carrying micro-droplets will carry. How long these stay aloft is dependent on convection, the HVAC system etc. But I am 100% confident that these droplets will extend way beyond 6 ft. As mentioned above, there is one report that just from loud talking (like at a bar) droplets can be projected around 30 ft. Given the limited HVAC systems most bars have, get two or three infected people in a bar, who are not wearing masks, talking loudly, singing, etc. and everyone in the room will breathe in some of their projected droplets. This probably explains the second outbreak in South Korea after they reopened bars. What’s by far the most popular bar in South Korea? Karaoke. (I know this because my son lived there for 2 years.) The combination of confined space and singing is a recipe for infectious transmission.
Of course, to produce even more aerosol projected even further, add sneezing and coughing. But there have been sufficient PSA’s explaining the need to cough/sneeze into your sleeve, so no need to repeat here.
With that in mind, here is what should NOT be done, indoors, without everyone involved wearing a good mask because the only good 6 ft social distancing will do is reduce the number of people in a room, which will reduce the probability of having an infected person in the room.
Now……back to the super spreader church cases. There are other mechanisms for spreading than the atomized spray. Someone coughing into their hand, then later shaking hands with others, who then touch their eyes and so forth. But by now, everyone understands the need to be more diligent with hand washing, avoiding such contact, and not touching your nose or eyes. So, I do not see these mechanisms as being much of a risk for causing a “second wave”.
The singing/shouting/huffing & puffing stuff, however, is very likely to result in virus spread. Until we get to herd immunity, these will inevitably result in deaths that could easily have been avoided with better understanding.
An aside…….I think there is also an explanation here for the extraordinarily high number of nursing home deaths we have seen. Many of these residents are confined to bed. The care givers, bless them, spend time in close contact with the residents; not just handling them, but also, at very close quarters, talking to them. How many of the residents are hard of hearing and the care giver has to elevate his/her voice? To increase vocal volume, you have to push out more air from your lungs, causing more virus to be released to the air in micro droplets that will linger. It is no wonder the transmission from care giver to nursing home resident has been so high. But easily avoided with the care giver wearing a decent mask.
To repeat myself. This analysis tells me we are making mistakes in what is being re-opened and that doing something like having people sit 6 ft apart in church is not going to stop the spread.
Be safe. Be well. Do good.
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