Masks protect us from the coronavirus, indoors as well as out. But do you really need a mask outdoors? In some cases, you can go bare-faced, but you should still have a mask in your pocket just in case. Let’s talk about the factors you should consider when deciding if a mask makes sense outdoors. (When in doubt, wear one anyway.)
Outdoor air dilutes the virus
One of the problems with indoor environments is that some of the respiratory droplets that can carry the virus are tiny. Indoors, the air containing these droplets has nowhere else to go. That’s why outdoor dining makes more sense than eating indoors, for example. The risk isn’t zero; there have definitely been super-spreader events at backyard parties and very likely a certain Rose Garden political event.
Many factors contribute to whether an interaction is likely to be a higher or lower COVID risk, and being outdoors generally takes the risk down a notch.
Brief encounters are low risk
Next we have to consider what you’re doing outdoors. Considering that Rose Garden event for a moment, should you wear a mask if you know you’re going to be near other people for hours, shaking hands and hugging? Absolutely. In fact, you probably shouldn’t go at all. That goes double if you know the other guests have been disregarding safety measures until now.
But passing somebody when you’re out jogging is a different scenario. To understand this more intuitively, it may make more sense to think of someone with bad breath or who has been smoking recently. Would the scent be overwhelming if you’re in the same park with a few such people? Or would you just detect a mild whiff as they pass you on the trail?
Very brief encounters, like passing someone as you jog or bike past them, may not be zero risk, but they are very low risk. “Any single brief, passing exposure is low-risk, but such exposures might add up over time,” airborne transmission expert Linsey Marr told the South China Morning Post. Wearing a mask makes sense if you’ll be encountering many people while you’re outside. It’s also a reasonable precaution even if you won’t.
Decide based on circumstances
It makes sense to think of the different layers of safety, and use a mask as one of them. If you’re outdoors, exposures are short, and people are nearly always more than six feet away, the mask doesn’t add much protection. If you’ll be encountering many people—for example, on a busy city street—a mask is a helpful safety layer to include.
I don’t wear a mask for most of my outdoor walks and runs, but that’s because I know I’m unlikely to come within six feet—or even ten feet—of anybody else. I go for walks on a quiet neighborhood street where I rarely pass anyone and can cross the street if I do. I go for runs on paths where I’m often the only person there.
But since I prefer to jog without a mask, I’ve given up my favorite running path, the one…