Recently, a set of videos have been circulating social media claiming to prove with scientific equipment that masks are extremely dangerous. The videos have been proof enough for many without a scientific understanding of chemistry and medicine that COVID-19 or not, we're better off not wearing a mask.

But what does the science say?

Many of you may be like me, finding mask-wearing pretty annoying. When I get home or into my car, I can't wait to take the stupid thing off. Why are they annoying, and why do they sometimes feel like it's hard to breathe?

When we aren't wearing a mask, air comes through our nose and/or mouth easily. It fills our lungs which diffuse the oxygen into our blood. Our lungs accomplish this by creating a low pressure environment in our chest. When this is exposed to the naturally high pressure of our atmosphere, high pressure moves into low pressure.

However, when we wear a mask, the air has a barrier to entry and this high to low pressure effect happens more slowly. To compensate, we need to make an even lower pressure environment in our lungs to get the same quantity of air in the same amount of time.

Having to use more effort to breathe can be stressful, but it's important not to confuse airflow with oxygen concentration. But isn't it bad to restrict your airflow? Not if you can increase it by breathing in harder. And that's why masks are annoying, but they still don't decrease oxygen concentration.

Even in the most restrictive of masks, O₂ and CO₂ can easily pass in and out.

The most restrictive masks in the consumer market are called N95. When worn snug to the face, these will filter out particles as small as 0.3 μm (microns). When we breath oxygen-containing air, Oxygen has about as much of a problem getting in as a dustmite would through a chain link fence.

When we breathe out, we expell a little Carbon Dioxide (CO₂). This also has no problem getting out of the mask even though it's twice as big on its longest side.

As an analogy, imagine I poured you a cup of tea and you drank the whole cup.

Next, imagine I poured you the same amount of tea, but in a heavier cup. Once you lift this one to your face, you will have exerted a greater effort to get it there, but you still get the same amount of tea.

For the same reason, you'll still get the same composition of air coming in the mask as you would from the outside.

Look at the diagram above showing the composition of everyday air. You'll notice there's a small percentage not shown here which accounts for very small components in the air like Argon.

If Oxygen levels decreased, that would mean Nitrogen (N₂) and CO₂ levels would increase. Given what we know, how could that be that oxygen didn't make it through the mask but these other very small molecules did?

What about these hazardous gas detectors?

In these videos we see what looks like scientific, professional equipment being used to expose (with scary warning sounds) a hazardously low oxygen environment! Should we panic?

Or given these masks are used during sometimes 12+ hour surgeries with no adverse effects, should we give into intuition that there may be some trickery going on here?

The explanation is pretty simple.

The test is essentially measuring a small reserve of non-moving air in between the man's face and the mask.

If you're wearing a mask and you're only getting your oxygen from that small pocket of air, you might as well wrap your entire face in plastic wrap. But if you're like really anyone, you're going to pull in air through and around the mask.

What is likely going on here at the moment the alarm goes off (remember, this is not a device meant to measure air in this way) is the man is breathing out. It just so happens, we know the composition of exhaled air.

The composition of CO₂ is 100-fold, but still very small and can diffuse through the mask to make way for a fresh intake of oxygen on inhale. However, during a constant stream of exhale, we easily see the oxygen concentration dips down to 16% as a result, triggering the alarm.

So how do we know masks are safe?

And if this isn't the way to measure oxygen, what is? It turns out that device is available pretty readily from your neighborhood pharmacy.

According to the American Lung Association, "If you have a symptom of shortness of breath or a known lung or heart condition, your doctor may use a pulse oximeter. The pulse oximeter, or Pulse Ox, is an electronic device that measures the saturation of oxygen carried in your red blood cells. Pulse oximeters can be attached to your fingers, forehead, nose, foot, ears or toes. The device may then be reused or disposed of...

The pulse oximeter, for example, a finger probe, uses a cold light source that shines a light through the fingertip, making the tip appear to be red. By analyzing the light from the light source that passes through the finger, the device is able to determine the percentage of oxygen in the red blood cell."

Later on, I'll show you real data from pulse oximeters showing masks are safe.

And what about the devices from these videos?

I decided to reach out to the manufacturer of one of the device shown in one of the videos

The device in question is the MX6 IBRID Six-Gas Monitor. When I wrote to the company, they immediately responded calling the act "misinformation"

Hi Adam,
You are probably questioning the need/safety of wearing a face covering/mask based on the videos and opinions of some that are floating around on the internet.
We have been getting many calls and e-mails regarding this because one of the videos shows our MX6 iBrid gas monitor being used in the misleading videos.
Please visit this link for a more researched explanation.
Dust masks have been used for many years in the safety industry without adverse effects.
Please call me with any questions.
Have a healthy & safe day!

According to the product manual for the IBRID MX6 Multi Gas Monitor,

"Sudden changes in atmospheric pressure may cause temporary fluctuations in the oxygen reading."

That's because it's designed to be used in a large space, not confined between a mask and someone's skin, where pressure will change with breathing.

The device has special manuals for the mining industry, refuge chambers, and mechanical pumps.

A warning label from the IBRID M6 manual. The device is primarily intended to measure large spaces and mechanical equipment. It is not a medical device.

It cannot be overstated, this is the wrong tool for the job.

But if you're still not convinced, here's yet another letter from a different manufacturer for a similar hazardous gas detector product from RKI Instruments:

RKI has been getting questions about using our gas detectors to check oxygen levels inside a mask. There is a video out that uses a GX-2009 to demonstrate oxygen levels inside a face mask, with the conclusion that the oxygen level is too low inside a mask and it is dangerous to be wearing a mask. In Ohio there is a bill to be voted on based on this that says wearing a mask is dangerous and so forcing people to do so should not be legislated.

It is very nice that our GX-2009 gets mentioned in the video! But the testing method and assumptions are incorrect. Otherwise everyone wearing masks would be passing out! Here is the video:

The sensor doesn’t react fast enough to be used for a test like this. When the wearer is exhaling, the oxygen level inside the mask will be very low, and the reading will go down. But, as soon as they start inhaling they will be drawing in fresh air. If inhaling and exhaling is only a few seconds each, the sensor cannot react fast enough to give the true instantaneous reading. The true reading would be that they are exhaling 14% to 18% oxygen, but inhaling 20.9%. But, due to the slower reaction time of the sensor, it will likely jump around 17% to 19% or so. Also, in the video they are only looking at the peak reading, so it will show the worst case.

If you put the GX-2009 right in front of your mouth without a mask on, and breathe in and out on the sensors, it will do about the same thing. In the video, he attempts to do this, but is breathing onto the face and top of the instrument, and even says the sensors are on the top. But the sensors are on the bottom. Since he isn’t breathing onto the sensors the reading stays at 20.9%. When the mask tests are done, they are putting the 2009 inside the masks in such a way that they are exhaling onto the sensors.

Medical professionals demonstrating mask safety with a pulse ox

But if you're like me and you want to see the evidence for yourself, here are tons of medical professionals performing the test the right way with the right equipment. Some of them took these results after working 10+ hour shifts!

Don't you want to get back to going to the movies, grabbing a beer with friends, shopping, and enjoying life like it once was? Just wear the damn mask!

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