Vincent Carroll — Should we be wearing masks outside?
Having misled the public initially on the usefulness of masks during the COVID-19 pandemic, government officials are now completing their 180 degree pivot, with Denver the latest large community to mandate that we wear masks in public indoor spaces.
If you read letters to the editor or follow social media, however, you know Denver’s mandate doesn’t go far enough for some people. They wear masks outdoors and expect everyone else to as well.
Are they right? Should government mandate face coverings outdoors, too?
Almost every aspect of the COVID-19 pandemic is fair game for debate, but given what we know at present, the transmission of the virus from people walking, running or biking outside appears unlikely, according to most accounts, if theoretically possible. So no, government should not mandate face coverings outdoors, absent new and more alarming evidence.
A study released last month that tracked 318 clusters of COVID-19 in China discovered outdoor transmission exceedingly rare. As the authors noted, “We identified only a single outbreak in an outdoor environment, which involved two cases.” For that matter, “All identified outbreaks of three or more cases occurred in an indoor environment, which confirms that sharing indoor space is a major SARSCoV-2 infection risk.”
Dr. Scott Gottlieb, the former FDA commissioner was so impressed he tweeted that the study raises the “chance for states to move services outdoors (religious, gym classes, restaurants, etc.)”
In another study, scientists captured air samples within two medical facilities in Wuhan, China, as well as in public places around the city. The New York Times reported, “Very little virus was detected in the air of the isolation wards or in the patient rooms of the hospital, which were well ventilated. But elevated concentrations were measured in the small toilet areas, about one square yard in size, which were not ventilated.”
Being outdoors is almost the definition of “well ventilated.”
“In the Wuhan research,” the Times continued, “no viruses were detected in most of the public places they studied, including the residential building and the supermarket.” The exceptions were “crowded areas outside of one of the hospitals” and — here I quote from the study itself — within “one crowd-gathering site about 1 meter to the entrance of a department store with customers frequently passing through.”
So an outdoor crowd might be problematic — except that we are talking about walking, running or biking in low-density communities like those in metro Denver.
Jonathan Kay, Canadian editor of quillette.com, cataloged 58 large COVID-19 infection clusters — superspreader events, or SSEs — and found that “almost all of the SSEs took place indoors, where people tend to pack closer together in social situations, and where ventilation is poorer.” The infection spread seems “to have involved the same type of behavior: extended, close-range, faceto-face conversation — typically in crowded, socially animated spaces.”
To be clear, some scientists do advocate wearing masks outdoors. But news articles also have quoted plenty of experts discounting the risk of a fleeting encounter on a sidewalk. From The Wall Street Journal: “If you are outdoors and appropriately distanced from other people, then it is highly unlikely you will be exposed,” said Henry Chambers, a professor in the Division of Infectious Diseases at the University of California, San Francisco.
I have worn a mask for weeks as a volunteer at a Meals on Wheels kitchen, and usually donned a mask within grocery stores. even before Denver’s mandate. But I am not going to torment myself about a remote possibility of infection when I am enjoying fresh air on daily walks.
I don’t wear a mask outdoors and have no intention of doing so. And I’m sorry if that makes some people uncomfortable. I will give them a smile and a wide berth and hope they understand.
A few days ago a motorcyclist passed me wearing a mask and no helmet. I suspect he has those two risk profiles exactly upside down.