I don't love wearing a mask. I must greet people with my eyes. I find myself yelling to be heard on rounds in the hospital. Small blemishes appear on my chin. Masks are bothersome. But I wear one. And though the mask covers my mouth, it speaks volumes.
It says I recognise we are all interconnected and I am making the choice to protect both myself and others. It also says I understand the ample evidence that masks can limit transmission of airborne illnesses.
In the midst of a pandemic which has left more than 150,000 Americans dead, it is our first line of defence.
So, as a pulmonary and critical-care doctor, it worries me that those who object to masks are increasingly using scientific sounding - but incorrect and misleading - discourse to promote their viewpoints.
This isn't just the usual idea that wearing masks somehow makes us less free, a premise which has created political turmoil throughout the pandemic, but the idea the act of wearing a mask can itself result in physical harm.
In a moment when we should be able to turn to science for collective safety, these claims instead make it all the more challenging for the public to separate fiction from reality.
Though much about Covid-19 remains unknown, we can say some things with certainty. The first is that wearing masks does limit the spread, by protecting others and those wearing them. We know now, from both laboratory studies and real-world data, masks are effective.
After a mask mandate for employees was put in place at the hospital system where I work, rates of coronavirus infections among health-care workers decreased.
On a more granular level, in late May two hair stylists in Missouri had close contact with 140 clients while infected with Covid-19. Everyone wore a mask. No one tested positive.
Despite such evidence, the internet is full of testimonials and even diagrams claiming masks lower oxygen levels and increase carbon dioxide. The idea here is that carbon dioxide is trapped within the mask and recycled when you breathe, leading to dangerously high levels in your blood, termed hypercapnia or CO2 intoxication.
While such conditions are possible under certain circumstances, such as in a severe exacerbation of emphysema or after a drugs overdose, this is not actually what happens when simply wearing a mask. The masks we wear in our daily lives, surgical masks or cloth face coverings, are not airtight. Carbon dioxide molecules are small enough to easily pass through.
That same rationale applies to the related idea that masks cause oxygen deprivation. The mask is not an impenetrable barrier. Just as carbon dioxide passes through and around a mask, oxygen enters. In fact, I have been wearing a surgical mask for 12 hours at a stretch at work, with an N95 mask when seeing coronavirus patients, and have never felt the dizziness or weakness characteristic of a low blood oxygen level.
With this in mind, some doctors have posted on Twitter about their normal oxygen levels after a long masked run. One layered six masks on his face while continuously measuring his oxygen level to prove it remained unchanged.
Of course, with severe lung disease, masks might be uncomfortable and worsen shortness of breath, and the far tighter N95 mask might pose some issues for those with severe lung disease if worn for long periods. But no one is recommending that the public wear N95s in their daily lives.
When you pause to think about it, it is rather amazing that a simple, harmless piece of material has the power to save lives.