Covid Mask Review

It looks like we will be wearing masks for a little while longer.  There is strong evidence that wearing a mask can help to stop the spread of Covid-19, and many states are requiring people to wear them out in public.   After making a few hundred masks for various organizations, I began to wonder, as I often do, which designs work best. 

Let me be clear from the beginning, I am not a medical professional (my background is engineering) and I don’t have access to fancy testing equipment. There is lots of evidence (like this) that heavy cotton can be effective at filtering virus sized particles, but clearly the fabric won’t filter anything if your breath doesn’t go through it. In an effort to test the different designs, my son came up with the great idea of using a vape to visualize what happens to our exhaled breath while wearing various masks.

First off, in most cases, an imperfect mask is still better than no mask. But, if you are interested in getting maximum protection from your mask, the most important thing is how tightly it fits your face. This controls how much of your breath actually goes through the mask. Air will always take the path of least resistance. Without a nose wire, all your breath will go straight up either side of your nose. If there are gaps on the sides of your mask or under your chin, that is where the air will go. I tested several types of masks and they are listed from worst to best. I have additional information about fit at the end.

Chin Mask.
For all of you out there who won’t wear a mask, or wear it incorrectly, you are being selfish and shortsighted. So you think “I am young and healthy, my chance of dying is really low. I should be able to do what I want.” Maybe you don’t care about the much greater chance of hospitalization and permanent damage to your heart or kidneys.

But, what about the people you are exposing to the virus? You go to the supermarket and you risk giving it to a person who works with the elderly, or has an at-risk child at home. Why is it that some people who claim to hold all life dear don’t have any problem with possibly killing their neighbor’s grandma?

Masks with Valves. I don’t think most people understand that masks with valves only filter the air on the way in. It doesn’t do anything for the air we exhale. Because we are wearing masks to protect others as well as ourselves, I would strongly recommend using a different type of mask.

Bandana Bandit Mask and Folded Alternative. I see lots of people using it. It looks comfortable and is reusable. I had no idea before performing this experiment how ineffective it is. But you can dramatically improve the performance by folding it down two more times so that you are breathing through 6 layers of fabric instead of 2.

CDC No Sew Bandana Mask.
This is from the CDC website but I don’t think it is that great. It is folded so many times (12 layers of fabric) that all the air goes over or under the mask. Personally I think you could just fold the bandana like I show in the second half of the Bandana Bandit video above.

Standard Rectangular Mask with and without a nose wire. You can see that without a nose wire, most of the exhaled air goes straight up either side of the nose. My personal opinion is that this is a great, easy reusable mask. Even without the nose wire, this mask is limiting how far the exhaled vapors can go.

If your mask doesn’t already have a nose wire, you can use a regular piece of tape to attach a wire, pipe cleaner, or unfolded paper clip to the outside of the mask (see my notes below).

Standard Paper Mask with a nose wire.
This mask is cheap and readily available. It doesn’t seem to be any better at filtering the air than the simplest reusable fabric mask and unfortunately, are ending up in land fills, waterways or as litter. For that reason I prefer a reusable mask.

3 Center Seam Face masks Compared. There are a lot of masks similar to this. The first one is the Florence face mask (previously called the Fu face mask) and the second one is my variation on the pattern and the third is the addition of a nose wire. Many of these center seam mask patterns have directions for a filter insert. Unless you are using a nose wire, the filter isn’t going to do any good since so little of the air flow will be going through it.

I like this style because of the way it curves up to cover my nose. Some of the other designs will ride up and get too close to my eyes. It is important to find a style of mask that is comfortable to you. If it doesn’t fit well, you will be touching it more often and be less likely to wear it. I believe that consistently wearing the mask is more important than any small improvement in design

This Pattern is called Best Fit
I wouldn’t say that this is the best, but what I do like about it is the use of craft/pony beads to make the straps adjustable. It also uses two pieces of wire held with electrical tape for over the nose. I think this works really well (see my recommendations about wire below). The downside to this design is the gathering at the sides of the mask. This causes space for air to escape out the sides. I much prefer pleats on the sides.

University of Florida, Prototype 2.
This pattern uses ties instead of elastic. I think that contributes to how well it fits. It is one of the best fitting masks that I measured. The fact that it sticks out from the face may make it less hot for the summer, but because it is so tight the fabric goes in and out with each breath which can be a little distracting.

AB Mask (By a Nurse for a Nurse)
Of the ones I tested, I believe that this is the best design. Not everybody likes the ties, but it results in a much better fit. The end of this video shows this same mask using elastic. As you can see the elastic pulls the edges of the mask together causing a gap on the sides of the face.

For people wondering if there is a difference in using batiks, quilter’s cotton, or heavy flannel, I wouldn’t worry about it so long as it is a heavy weight fabric. I ran this experiment with all those fabrics and there wasn’t enough of a difference for this VERY rough analysis to make a positive determination. If you are worried that it isn’t heavy enough, feel free to add one or two extra layers.

Medical Masks.
The first is a Kimberly Clark surgical mask with a nose wire and double sided tape, given to me at my doctor’s office.
The second is an N95 mask, left over from before the pandemic. (My husband is a woodworker.)

Not surprisingly, these work better than quilting fabric, but they should be saved for medical professionals. As you can see, without professional fitting, they still aren’t perfect.

Nose wire options
It is clear that nose wires dramatically improve the performance of masks but there is some question about what to use. If you are making a mask or looking to insert a wire into a reusable mask you should avoid pipe cleaners as they rust very quickly. I tried 18 gauge aluminum craft wire, but it broke after only a few washings. The best wire I found is OOK brand 18 gauge copper craft wire which can be found at Home Depot. My second favorite choice is Vigoro garden training wire also found at Home Depot.

What if you already have a reusable mask and it doesn’t have a nose wire?
Just tape a wire to the outside of a mask
Never fear, a small piece of tape and some wire and you are good to go. Because the wire is just taped on, and won’t be washed, you can use any sort of wire from a pipe cleaner to a straightened out paper clip.

As you can see from the video, a piece of tape can attach a wire to the outside of your mask and works just as well as an internal wire.

For those who Don’t Like Nose Wires.
I understand that there are people who don’t like the feel of the nose wire. I have seen plenty of people wear paper masks without bending the wire to conform to their noses. I wondered if there is anything that could reduce the air going up by the nose. A good friend of mine suggested goggles to hold that part of the mask against the face. That will certainly work, but not everyone has or wants to wear goggles when they go out. Instead I came up with two alternatives. The first is for people who are sewing their own masks.

Nose Pillows

I took two small triangles of fabric, stuffed them with batting and sewed them on either side of the center top of the mask.

Double Sided Tape
Adding a 4″ piece of double sided tape to the center top inside of the mask helps stick it to your nose. You will have to reapply the tape each time you go out and probably wouldn’t be good for all day wear.

Two alternatives to using nose wires.
This video shows a rectangular mask with nothing over the nose, then using nose pillows, then two sided tape then a nose wire for comparison. As you can see, the tape and pillows aren’t as good as a wire, but are significantly better than nothing

In conclusion, properly worn, well fitting face masks can help all of us stay healthy and help stop the spread of this virus. By being aware of which designs work better than others, and simple ways we can improve the fit of the masks we have, we can hasten the day when we won’t have to wear them every time we go out.

7 Replies to “Covid Mask Review”

  1. Great article. Got a lot out of the comparisons. Loved the way that was done. Kudos to your son for coming up with the demo ides and participating. Best reminder that the masks are not mainly to protect the wearer but to put those around you first.

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