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The Limits of Mask Ordinances

Masks are important. But there are a lot of indoor risks that recent mask mandates don’t address.

Alex Wong/Getty Images
D.C. Mayor Muriel Bowser

Washington, D.C., has become the latest major city to require masks outside the home. Mayor Muriel Bowser signed the executive order on Wednesday; it will last for at least the next two and a half months, and those who violate the rule could face a fine as high as $1,000. “Basically, what it says is if you leave home, you should wear a mask,” Bowser said at a press conference. Walking your dog, waiting for the bus, riding on public transportation, and in taxis and ridesharing arrangements—any time you’re likely to come in contact with a person, which includes being within six feet of them “for more than a fleeting time,” a mask is required.

The mask mandate drops into a complicated environment. Masks clearly help prevent the spread of SARS-CoV-2, the coronavirus that causes Covid-19—with cloth masks mostly serving as what the experts call “source control,” blocking what comes out of a person’s mouth. Anti-maskers, complaining that masks infringe upon their freedom, have become a serious problem for many business owners as well as policymakers trying to bring the pandemic under control. Bowser’s order was announced as D.C. cases rise once more, after finally slowing in June.

At the same time, masks have their limits in controlling the pandemic—and while normalizing their use is important, it’s not the only measure needed to slow the spread of the coronavirus.

Although Bowser’s mandate requires masks while ordering food at restaurants, diners may take off their masks to eat. There are also exceptions for people who are drinking or smoking, engaged in “vigorous outdoor exercise,” under the age of 2, working alone in enclosed offices, interacting with someone who is deaf or hard of hearing, or medically unable to wear masks. Masks are also not required at home. While all of those exceptions make sense, they also highlight major flaws in making public mask-wearing the primary way of fighting Covid-19.

“Time spent indoors is one of the biggest risk factors for transmission of SARS-CoV-2, the virus that causes Covid-19,” Joseph Allen, an assistant professor of exposure assessment science at the Harvard T.H. Chan School of Public Health, told me. Staying outside, masked but also at a distance, helps lower the odds of getting sick, and improving ventilation indoors also helps immensely. Researchers have started suggesting all of these measures in the past few months, as evidence accumulated that the virus can be transmitted via airborne particles if there’s insufficient air circulation, something that’s far more likely indoors than outdoors.

Yet mask requirements don’t do much to address indoor transmission. In D.C., as in many areas where mask requirements have been imposed, restaurants and bars remain open. Despite distance put between diners, a recent study from JPMorgan found that card expenses toward restaurant dining were “particularly predictive” of later virus spread. While removing masks to eat, as the current D.C. order allows, makes logistical sense—science has come a long way, but we still haven’t figured out how to eat while keeping a mask on—it also highlights how hard it actually is to make indoor dining safe.

“Six feet is good, obviously 10 feet is better, but if you’re around a lot of people, even if you’re within six feet, you should still be wearing a mask,” Saskia Popescu, a hospital epidemiologist and infection preventionist, told me. When it comes to managing risks, she also recommends making decisions based on the environment you’re in. “Do you have airflow, do you have natural ventilation, how small is the space? And then, is it an enclosed space with a lot of people—you look at how many people are in that environment with you and for how long.”

Airflow is a particularly complicated factor. Many restaurants, offices, homes, schools, churches, and other indoor spaces involve ventilation systems that recirculate at least part of the air. In one case study of a restaurant in Guangzhou, China, a diner with no symptoms sat in front of an air-conditioning vent, which pushed viral particles through the air—more than six feet—and sickened diners downwind. Those outside of the vent’s path were fine.

“If you can’t bring in higher rates of outdoor air, you want to increase the filtration of the air that is recirculated,” Allen told me. That can be done by installing high-quality filters in the existing heating, ventilation, and air conditioning systems or by using portable HEPA filters in the rooms themselves. But as of right now, local ordinances focused on mask-wearing don’t require that. People who live, work, or eat in buildings where the air is recirculated but not well filtered may never even know that they’re at higher risk. “Look, we know how this is spread,” Popescu said. “People in close contact for prolonged periods of time, like household contacts—that’s the high-risk interaction that’s going to get people sick.”

While wearing a mask is important, the broader policy solutions that could help contain Covid-19, though expensive, are well known by now. Investing in widely available and quick-turnaround tests and contact tracing is perhaps most important. Upgrading building ventilation is another. So is strengthening the social safety net with sick leave, safe housing, universal health care, unemployment, and other policies—all of which will help halt workplace transmission for people with Covid-19.

Relying solely on masks to control the pandemic is more difficult for those who face discrimination because of their mask-wearing. There have been accounts of racism against masked people of color, including a case in May where two Black men were escorted out of a Walmart by an armed guard because they were wearing masks. Georges Benjamin, executive director of the American Public Health Association, called it “the masking-while-Black phenomenon.”

“We tell everybody: wear a mask,” Benjamin told me. “Of course, many African American men don’t want to wear a mask because they’re afraid of being profiled.” Wearing a mask in a bank, for instance, seems particularly risky for many people—but especially people of color, Benjamin said. There may also be racial disparities in how mask mandates are enforced, with people of color more likely to be stopped and fined.

Joshua Santarpia, an associate professor of pathology and microbiology at the University of Nebraska Medical Center, told me that he wishes people had more guidance from health officials on which materials are best for masks and how to wear them properly—including putting them on and taking them off without becoming infected in the process. “I really need, want, someone to come in and say, please, make your mask like this, do it like this,” he said. He recommended making different standard sizes and widths, like shoe sizes. “We need better masks for people—better fitting, better quality,” he said.

Santarpia also cautioned against relying too much on a mask to protect yourself without taking any of the other necessary precautions. “If you’re going to go to the store, going to do whatever, right, wear a mask. But don’t think that your mask gives you an excuse to do things exactly the way you’ve always done them,” he said. “Just because I’m wearing a piece of fabric over my face doesn’t mean I can go in a crowded bar and expect that that guy, you know, five [feet] away from me who’s got coronavirus isn’t giving it to me, because he probably is.”

Normalizing mask use is an important part of addressing the coronavirus pandemic. But it’s not the only answer. Making indoor environments safer while continuing to expand quick, free, easily available testing, contact tracing, and treatment will be decisive in getting the current pandemic under control—and preventing pandemics in the future. Donning masks is vital. It’s not magical.