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Mitigating COVID Transmission Risk in Indoor Settings


Real science is never settled, and anyone who has certainty on such things is not qualified to discuss it.


I am unaware of any credible scientific study proving that masks as actually worn by the public do anything to reduce community transmission. Let alone the half dozen studies that would have to replicate such results to begin to achieve moderate scientific credibility. Let alone a randomized controlled study with a p-value of even -0.05. Junk science abounds for political purposes and that’s all there is from what I see.

The foregoing is different from saying “masks do not work”, because of course good masks properly fitted (N95/N100 particulate respirators) must surely have some benefit in at least some circumstances. But that is entirely different from the toy masks worn by most of the public, what with highly breathable masks now being marketed to avoid discomfort, thus making a mockery of the whole idea of masks blocking/trapping virus droplets. Ditto for masks worn repeatedly, masks below the nose or partially covering it, etc.


Hypothesis: COVID spreads primarily from plumes of virus-laden air spewed out by heavy breathing, coughing, singing, talking loudly or at length, etc. Think of a diesel bus exhaust pipe, and you get the idea—you can see how that filth spreads out from the tailpipe.

What might mitigate such transmission:

  • Masks, by blocking the plume, though ample COVID still escapes. See above.
  • Air movement: open windows that allow significant airflow, e.g., wind blowing in that disperses plumes.
  • Air movement: always-on fans that quickly disperse plumes. This is quite different form ventilation systems, which frequently have inadequate or weak air movement where people actually sit/stand.
  • Air cleaning: HEPA air filters (also de facto fans). Actively remove virii and dust and so on while also continually circulating air.
  • Zapping solutions like UV light in air ducts.

It’s clear from my wife and daughter being infected (and wearing masks in all their contact settings!) that transmission requires very little exposure, and that masks sure seem to have done jack shit for them. Still, the plume theory has as much credibility as anything I can think of.

Of course, if you spend hours in a room with an infected person, even with fans/ventilation there could be significant buildup of virus.

The Epoch Times: Fauci Says Mask Should Still Be Worn, Even If Vaccinated Against COVID-19

2021-12-20 by Katabella Roberts. Emphasis added.

...American Airlines CEO Doug Parker, Southwest Airlines CEO Gary Kelly, and United Airlines CEO Scott Kirby made the comments during a Senate Commerce Committee hearing on aviation issues, where they explained that the air quality on flights was far superior to that in many indoor spaces such as theatres, churches, and even hospitals, due to the planes’ high-efficiency particulate air (HEPA) filters.

Referring to the high number of airborne particles captured by HEPA filters, Southwest’s Kelly said, “I think the case is very strong that masks don’t add much, if anything, in the air cabin environment. It is very safe and very high quality compared to any other indoor setting.”

“I concur,” said Parker from American Airlines. “An aircraft is the safest place you can be. It’s true of all of our aircraft—they all have the same HEPA filters and airflow.”

However, Sara Nelson, president of the Association of Flight Attendants, pointed out that not all planes are fitted with the same quality of air filters, and said she believed that masks should continue to be worn during flights as part of a “layered safety protocol.”

WIND: the claims might be true, but if an infected person were next to you on an airplane, would you want their face turned towards you while the breath or talk?

It would be wise to turn on the air jet over yet seat, centered on your face. That air should be HEPA-filtered.

OTOH, how many times have you gagged on fumes from the jet engines, the stench coming from the airplane air vents? It might be filtered, but at the least there is no activated charcoal involved and maybe it’s filtered a lot less well than claimed.

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