Image of a nurse sporting an orange surgical mask

COVID-19: Are You Masking the Problem?

In Simple But Not Easy, I wrote about COVID-19 vectors of transmission. If you didn’t read it, please do so now so you you have a contextual basis for my arguments.

Who Can You Believe?

There has been a lot of contradictory advice over whether or not to wear a mask, surgical or otherwise, to prevent the spread of COVID-19. As of this writing, the WHO is still advising that if you do not have any [COVID-19] symptoms, you do not have to wear masks because there is no evidence that they protect people who are not sick. [UPDATE: the WHO revised it’s advisement on mask wearing on June 5th and again June 19th, 2020. I feel they need to do more to bring their advice in line with current best practises. ]

I’m sorry but this advice is both misguided and outdated! There is a growing body of evidence that airborne droplets or aerosols can stay in the air much longer than we thought and that masks do protect people who are not sick!

Even if there were no direct evidence that wearing a mask offered any protection, it’s still the prudent thing to do. Why take the chance?

Asian countries such as China and Taiwan have taken the lead when it comes to mask wearing and they have statistics to back up their effectiveness. And yet the stance taken by the WHO and others suggests that they still believe COVID-19 is not an airborne disease. According to CDC guidelines, Airborne transmission occurs by dissemination of either airborne droplet nuclei or small particles in the respirable size range containing infectious agents that remain infective over time and distance.

If you have contracted COVID-19 and you don’t know you are infected […] wearing a mask will reduce the spread from your own coughs, sneezes or even breathing.

The 2-metre (6-foot) physical-distancing rule is based on the premise that body fluid is expelled every time you cough or sneeze. The larger of these fluid droplets don’t fit the definition of airborne because they are thought to be relatively heavy projectiles that fall out of the air quickly.

However, new modelling and testing have confirmed that, while the heavier droplets do fall out of the air, the smaller droplets, or “aerosols”, can stay airborne for quite a long time, in some cases, long after the infected person has left the room. It all suggests that physical distancing is not enough!

How About Eye Protection?

A mask won’t protect your eyes if someone sneezes or coughs within the 2 metre (6 ft) higher-risk zone. One could also argue that suspended aerosols could still make contact with your eyes long after the cough or sneeze or beyond the 2 metre distancing, but at least your eyes don’t inhale particles like your noise and mouth can.

Just yesterday at Starbucks I saw a barista wearing a full plastic face shield like the ones that some healthcare professionals are using. That is one solution. The barista, however, was not wearing a mask under her shield as she should!

I also saw a woman on the bus wearing goggles with indirect vents. A quick search and I discovered “Splash Shield Safety Goggles” on Amazon that looked identical. These address the problem while being significantly cheaper than the full face shield.

What about the Mask Shortage?

One argument I often hear (from the WHO and others) is that the increased demand by the public for face masks contributes to the shortage of N95 masks and surgical masks needed by hospital workers. They site that as reason not to wear a mask.

However, the primary goal is not to contract COVID-19 so that we don’t become a burden to the hospital in the first place. Masks are a compliment to physical distancing and there are statistics to prove it that they contribute to flattening the curve, even if it isn’t to the same degree as our hand washing and cancelled events.

Sure, there is a shortage of masks for our healthcare professionals, but citing this as a reason not to wear a mask is broken logic. We are, after all, all in this together.

[2020-07-24 UPDATE: There is no longer a shortage of masks. You can buy 3-ply, non-woven fibre, surgical-style masks at most retailers and the less-effective washable fabric masks.]


Another criticism we hear is that improper mask use is worse than no mask at all. I agree that improper use of masks is a problem. I see it every day. This is a educational and behavioural problem not a mask problem!

If you are removing your mask to take a sip of your coffee then stop drinking coffee until you find a safe place to take off your mask. If you have to adjust or remove your mask, sanitising your hands first.

Forget Everything You’ve Been Told About not Wearing a Mask!

There is absolutely is evidence that masks do protect people who are not sick, and they do so in two ways:

  1. If you have contracted COVID-19 and you don’t know you are infected you don’t want to spread the infection to others. Wearing a mask will reduce the spread from your own coughs, sneezes or even breathing.
  2. If you are anywhere near an infected person who is not wearing a mask, your own mask will offer some protection against inhaling aerosols from the coughs, sneezes or breathing those who are infected.

Even if there were no direct evidence that wearing a mask offered any protection, it’s still the prudent thing to do. Why take the chance?

In addition to wearing a mask, your best defence is still a combination of physical distancing, hand sanitising, and not touching your face.

What Kind of Mask Should I Wear?

The highest level of protection comes from “filtering face-piece respirators”, better known as N95 masks, which are made of a non-woven fibre and provide a good seal around the edges. N95 is a NIOSH rating. The N mean that they are only rated for use in a non-oily environment. An R rating says it resistant to oil for 8 hours and a P rating tells us the mask is oil proof. The number is the efficiency. N95 masksare 95% efficient. N100 masks are about 99.97% efficient, which meets HEPA standards.

Some masks are fitted with an exhale valve. These masks offer a higher degree of comfort and protection to the people wearing them but, since the valve allows unfiltered exhalation, they offer no protection to bystanders. (It reminds me of the side-stream smoke problem with cigarettes.)

The next category would be the surgical mask. These masks are approved by the US FDA for medical and dental use. They offer less protection to the wearer than the N95s because they don’t provide a good seal around the edges. They are designed to protect the patient from the droplet exhalations of the operating room staff but are often used in patient settings to protect the medical professional from exposure by the patient.

Single-use face masks are similar to surgical masks but are not rated for medical use. They are economical and do offer some protection.

The last category I would call “improvised” or “DIY” masks. Any home-made mask, fits this category. The amount of protection depends on its fit and the materials used.

See CDC: Simple Respiratory Mask for how to improvise a mask from T-shirt fabric. Their tests shows that “a hand-fashioned mask can provide a good fit and a measurable level of protection from a challenge aerosol”. However, this Cambridge study suggests that fit factor, air resistance and filtration effectiveness vary widely with the material used. The most practical material seems to be about 2 layers of stretchy T-shirt fabric.

There is no question that an N95 or higher respirator mask provides the highest level of protection for the wearer. These should also be non-valved types to prevent your unfiltered breath from exiting the mask.

The Supply Problem

As N95 masks are currently in short supply, if you are not already suspected or confirmed positive for COVID-19 then you should leave the N95s to the medical professionals, at least until the current shortage is alleviated.

A surgical mask is your next choice. These too may be in short supply, depending on your locale. As with the N95s, you should leave these for the medical professions until such time as supplies are ample.

So that leaves us with the single use face masks or DIY masks. These will offer better protection than no mask at all, especially if you can combine them with maintaining physical distancing.

If you decide to make your own mask, keep in mind that a single layer of cotton does not provide enough protection. If you can use three layers of T-shirt cotton and still find it easy to breath, then use three layers. If you find it difficult to breath with three, then try two layers.

I would still wear a bandana in the absence of better materials, such as t-shirt cotton. The bottom line is any face protection is better than nothing.

Don't Forget...

  • keep your hands clean/sanitised
  • don't touch your face without first cleaning/sanitising
  • practise physical distancing
  • completely cover your coughs and sneezes
  • and finally, wear mask!!!

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