We know now the main way the novel coronavirus that causes COVID-19 spreads is through the air in droplets an infected person breathes out. And we know that clouds of the tiniest of these droplets, called an aerosol, can linger in the air for up to an hour. This is why, until everyone is vaccinated everywhere in the world, masks are our best defense against the pandemic along with physical distancing and washing our hands.
So, sure, we’re all tired of wearing masks, just like we’re tired of staying home and wish we could visit friends and relatives on the other side of those closed borders. But images of ICUs and descriptions of “long COVID” help us to be patient… and reports of how contagious some of the variants can be are convincing of the danger that is still out there. We all want to avoid that.
So what’s the best mask available to us?
3 basic types of masks
There are 3 main types of masks: the N-95, disposable medical masks, and cloth masks. Keep in mind that any mask is better than none, but they are only as effective as the fit around your face. All air must be breathed through the mask in order to be filtered. Any air that escapes around the mask because of gaps in the fit can carry virus into the person’s airway or, in the case of someone who is infected, out into the air for someone else to breathe in.
I discovered that the Centers for Disease Control and Prevention (CDC) in the USA did some research on masks in January of this year. They found that there’s more than one way to get a high level of protection from the masks that are available to us.
The N95 mask
N95 masks, also referred to as respirators, are the gold standard and are strongly recommended for healthcare workers who are working closely with patients who have (or are suspected of having) the novel coronavirus. At the beginning of the pandemic, there was such concern that the public would buy up all available masks, along with no studies to prove they helped (since the virus was so new), that authorities told the public not to use masks at all.
However, it’s been over a year now… enough time to learn that the virus travels through the air and to manufacture all the masks the public might want to buy. I see N95s at my local Costco, always in stock, these days. But is it the best mask to wear when you go shopping or enter a public place?
It might not be. But you should be aware that an N95 mask is harder to breathe through because of its higher filtration. It also only works to filter 95% of particles you breathe in if it is fitted tightly to the face. When fitted properly, it will leave a reddened line or dent in the face where it seals after just a few hours of wear. You may need to adjust the ear loops by tying a knot in them to make sure the mask is pressed securely against your face. Many of us would be uncomfortable wearing one for any length of time unless we were required to do so for our work. You do get used to them after a while…
Medical procedure (surgical) masks
The flat, pleated medical procedure masks, also called surgical masks, are made with 3 layers of good quality filtering material but, because of their design, they typically don’t create a good seal around the face. This allows air to leak around the mask, reducing its filtering ability. The CDC’s study showed we could expect about 56% blockage of particles from a medical mask alone that is worn properly.
Knotting ear loops
Another method of improving the fit of a medical mask they tested, was to tie a knot in the ear loop close to the fabric then tuck in the sides. This pulls the medical mask more into the shape of the N95 mask, greatly reducing gaps on the sides and around the nose. One study found this alone improved filtration to at least 77% of particles.
Cloth masks
Homemade cloth masks were the first alternative suggested to medical masks that were difficult to find a year ago. The initial recommendation was to make one from 2 layers of tightly woven cotton fabric or heavy t-shirt material but, with research, that was upgraded to recommending 3 layers of different fabrics, ideally one of them being non-woven material. There are lots of patterns for sewn or folded masks (that don’t require sewing) on the internet and, of course, you can buy cloth masks anywhere now. I wish I’d known that I could have cut up a t-shirt for some protection on our trip home from Spain in March 2020! The CDC study found approximately 51% reduction in inhaled particles using a 3-layer cotton cloth mask, and this would very with the materials used.
One advantage of cloth masks is that they are washable, so you don’t have to worry about supply. Plus you can individualize them, adjusting the loops and shape if needed, so they fit your face snugly. You can even have fun with designs and colours—I love the “matching” look :) and comical ones. However, the filtering capacity varies widely depending on the fabric used. When I sewed masks, I put a pocket for a filter on the inside so users could increase the filtration according to changing recommendations. Blue shop towels were one recommendation for a non-woven filter, and I used these in my masks until the most recent recommendation – double masking.
Double masking
I started noticing people on TV wearing two masks in late January. It turns out that this technique is based on the research by the CDC mentioned above. The fabric medical masks are made from filters well – the problem is leakage around the edges of the mask where gaps often occur because of the curves of the face. Woven cotton, especially when cut on the bias (diagonal), and knitted fabrics have some stretch and can mold to the face better than medical mask material.
As well, when a mask is sewn, it can be sized and shaped to fit over the nose and chin and tucks can be added wherever they are needed to fit the shape of the individual’s face. When I was sewing masks for family and friends last year, I was surprised that a mask that fit most faces would gap badly on others or just be so large it would slide off and not filter at all. Faces come in all sizes and shapes! I ended up making 3 different sizes for adults and added extra tucks for my hubby’s masks.
So the CDC looked at 2 options: placing a well-fitting cloth mask over a medical procedure mask and tying the ear loops to improve the fit. Both approaches significantly improved the filtration ability of the medical mask.
Combining 2 methods
They tested combinations of either 2 masks used together, or a medical mask tied and tucked as described (and shown in the photo above). Here are some numbers from their studies:
Doubled or tied mask with a simulated cough (exhalation) and unmasked reciever – 85.4% reduction in particles exhaled
Inhaling with doubled or tied mask, with an unmasked source – 82.2% reduction in particles inhaled
With both the source and receiver with doubled mask – cumulative reduction in exposure of 96.4%
With both the source and receiver using a tied mask – cumulative reduction of 95.9%
The study also commented on mask fitters (small, shaped devices worn over a medical mask to seal it to the face), and covering a medical mask with a stretchy, close-fitting fabric, like a length of pantyhose fabric or a “gator” necesita scarf. Both these techniques were found in two other studies to give similar results to double masking. Mask fitters are also referred to as a mask seal or brace, and are worn on top of a face covering to improve fit. You can buy these already made or make your own. Here are some videos and instructions. The last example, on slide 35, is the simplest to make and, if making for yourself, you can just knot the elastic to fit rather than using slide clamps, if you don’t have access to these.
Can you just layer 2 medical masks?
No. The CDC notes that layering 2 medical procedure masks does not give similar results, as this does not improve the fit. They also recommend choosing cloth masks with a nose wire to ensure a good fit over the nose.
So, you might want to consider using an N95 mask, now that they are more readily available, if someone in your household has COVID or if you are in some other higher-risk situation. However, using a medical mask with either a well-fitting cloth mask over it, tying the ear loops to improve the fit, or using a mask fitter will work very well in most situations you will encounter in public. Now that variants are spreading, it's worthwhile to take that extra step to ensure good filtration and good fit for whatever mask you choose to use.
One last bit of COVID news…
As you know, I’m always reading quirky heath news. Here’s an interesting one for you. Flushing a toilet or urinal creates aerosols... and we know that those with COVID excrete the virus (they can actually detect whether anyone using the “facilities” in a building has it by doing a single test of its wastewater). So, the advice, if you need to use a public restroom, is to flush then get the heck out of there quickly. I'll probably wear a mask in public washrooms from now on, even when COVID is long over with…
References:
More scientists now believe COVID-19 spreads primarily through the air -- CTV News
Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 – Centers for Disease Control and Prevention (CDC)
Double masking can block 92% of infectious particles, CDC says – CNN Health
What you need to know about face masks as protection against coronavirus – CNN
How to make a Badger Seal – University of Wisconsin-Madison
Don't linger after you flush -- CTV News
