Surgical-style face masks can slightly reduce the risk of transmitting respiratory infections, but are they really a good strategy for protecting yourself? Yes and no—here’s the deal.
Masks don’t completely block out germs
When you breathe in, a mask filters the air and particles above a certain size cannot get through. That’s the idea behind wearing a tight-fitting N95 mask when there’s a lot of soot or smoke in the air, for example. Hospital staff treating suspected coronavirus patients are also recommended to wear an N95 mask to see those patients.
But when you see somebody wearing a mask walking down the street, it’s typically a surgical mask. Surgical masks aren’t designed to block particles of a particular size, and viruses are smaller than soot particles, anyway. That said, a mask can provide a little bit of protection against droplets of bodily fluids (think about the spray that occurs when you sneeze or cough).
But there’s another issue: surgical masks aren’t tight fitting. That means air can easily get in between the mask and your skin, so that you’re breathing some amount of unfiltered air.
The U.S. CDC has this handy chart on the difference between surgical masks and respirators, but the bottom line is they don’t recommend either one for everyday protection from other people’s germs. If you’re travelling, they recommend other measures, like washing your hands often and—as of an alert yesterday—avoiding unnecessary travel to China.
Masks stop you from getting your germs everywhere
The proper use of a surgical mask is not to protect yourself from other people, but to protect other people from your germs.
When you cough or sneeze, all those droplets will end up on the inside of your mask. Eventually you’ll get grossed out enough to change or clean your mask. This reduces the amount of potentially virus-laden droplets that people around you are exposed to.
That’s why surgeons wear masks during surgery (you wouldn’t want somebody breathing into your open wounds, even if they’re relatively healthy) and it’s why, if you go to a clinic when you have cold or flu symptoms, you might be asked to wear a mask in the waiting room.
It’s fine to wear a mask if you prefer
I personally wouldn’t want to wear a mask walking down the street, because I feel like everyone would be like: who’s that weirdo in the mask? It’s just not common where I live.
But masks are a lot more socially acceptable in Asia, where their popularity can be traced to the 2003 SARS epidemic. Maybe you’re protecting yourself from others’ germs; maybe you have a cold and want to be sure you’re not spreading anything anyway.
I wouldn’t be surprised if masks being commonplace means slightly reduced transmission of respiratory viruses. Masks may not help you avoid germs, but they’re also unlikely to hurt, so feel free to wear one if you prefer.