NEWS RELEASE                                                                                     October 2020

A BB Gun in Bear Country is Like a Cloth Mask at a Rally

Grizzly bears are as tough to stop as the coronavirus. Even relatively high powered guns may not stop the charge. No one would recommend a BB gun for protection. Yet a BB gun to stop a bear is as illogical as a loose fitting inefficient mask to protect against COVID.

When the guidance is to wear a mask without specifying  the level of protection, it is equivalent to telling people that any kind of gun will protect them in bear country. The false sense of security could be doing huge damage. Some studies show that 70 percent of the COVID cases occur in people who are wearing masks. This coincidently ties into the likely efficiency of a cloth ill-fitting mask. If everyone is wearing inefficient masks you would expect only 20 percent better protection than if no masks were worn.

Mask inefficiency is a subject many experts are avoiding because they worry that this fact will be used to persuade people not to wear masks at all. Some experts such as Professor Osterholm of the University of Minnesota express the opposite view. He worries that people will feel safer than they should and will venture into risky situations with a false sense of security.

What is particularly puzzling is that no one argues about the physics and yet there is no major campaign to encourage use of efficient and tight fitting masks.

  • Medical personnel in the best PPE are close to 100% protected against the virus even if the virus load is extremely high.
  • If everyone wore this garb for four weeks the virus would be gone.
  • The virus is only 100 nanometers or 0.1 microns in diameter.
  • It is frequently carried on 1 micron and larger droplets.
  • These droplets evaporate.
  • The salts remaining after evaporation vary in size but are much smaller than the droplet.
  • Large droplets captured on the inside surfaces of masks are either divided into smaller droplets by air flow back and forth or they evaporate.
  • Particles adhering to media surfaces will very likely not become airborne but particles in droplets which evaporate can penetrate the mask or flow out the leaks around the mask periphery.
  • Most masks worn by the public are loose fitting. The amount of air circumventing the media is often 50% or more.
  • It is misleading to judge the mask fit by the leakage of all particles. It is the small virus which will act like perfume or cigarette smoke and penetrate any opening.
  • Most masks have a very low efficiency on perfume or cigarette smoke and therefore are just as inefficient on viruses.
  • When you combine the virus which is inhaled around the periphery of the mask with the virus which penetrates, it is likely that the total efficiency is as low as 20%.

Inefficient Loose Fitting Cloth Mask


This is assuming that the wearer has the mask in the proper position.

Efficient Tight Fitting Mask


An efficient tight fitting mask will only allow 3 percent of the virus to penetrate and 2 percent to be inhaled through the periphery.

It is very important that this mask knowledge be continually assessed and debated. Engineers and aerosol scientists cannot disregard the physics just described. The one variable where the medical community has superior knowledge is the viability of the virus. Does the virus initially captured in a large droplet become inactive as the droplet evaporates and it becomes airborne? The opposite seems be true with documented cases of aerosol viability 24 hours after exhalation.

Does a massive instantaneous dose of virus cause more harm than if that dose is metered out over 15 minutes?  There is some evidence that the opposite is true. Some super spreader events such as the Washington state choir imply that continuous exposure over an hour is likely to cause transmission.

If in fact reliance on cloth masks is as dangerous as relying on a BB gun in bear country, it is very important to gain a consensus on the dangers. The daily alerts and webinars included in Coronavirus Technology Solutions provide a forum to analyze all aspects in depth. Click here for more information

Bob McIlvaine can answer your questions at  847 226 2391 or email This email address is being protected from spambots. You need JavaScript enabled to view it..