It seems just about every time a media outlet runs a story about people being irresponsible during the COVID-19 pandemic, some editor slaps in a photo or video clip of people gathered on beaches.
But beaches are getting an unfair rap, and such displays only sow confusion among the public because they fly in the face of sensible intuition — and science.
It’s critical to understand how the novel coronavirus — aka SARS-CoV-2 — actually causes infection. Erin S. Bromage, Ph.D., associate professor of Biology at the University of Massachusetts Dartmouth, puts it succinctly: “Successful infection=exposure to virus+time.”
In any enclosed space, or amid a tightly packed crowd, both time and exposure (i.e. more viral particles) are likely to increase, including if air is being recirculated. It’s critically important to reduce the chance that you are expelling virus in such environments by wearing an effective mask — more on that below.
But outside, it’s a totally different ball game.
“If you are sitting in a well-ventilated space, with few people, the risk is low,” Bromage says. “(R)emember, it is ‘dose and time needed for infection.”
“Outside, things like sunlight, wind, rain, ambient temperature and humidity can affect virus infectivity and transmissibility, so while we can’t say there’s zero risk, it’s likely low unless you are engaging in activities as part of a large crowd (such as a protest),” Angela Rasmussen, a virologist at Columbia University, told Vox.
The risk is so low, in fact, that it’s not far from zero. When The New York Times went in search of a documented outdoor transmission, it rummaged up a single case out of 7,300 studied in China — that’s less than 0.0000014 percent. And that patient had been closely speaking with an infected person, not riding a bike, walking a beach or jogging.
If you walk past someone outdoors, Bromage explains, you would “have to be in their airstream for 5+ minutes for a chance of infection. While joggers may be releasing more virus due to deep breathing, remember the exposure time is also less due to their speed. Please do maintain physical distance, but the risk of infection in these scenarios (is) low.”
“Viral load” is the number of particles being expelled into the air via breathing, coughing, sneezing, even singing or shouting. Generally, the more violent the expulsion, the more particles are expelled. Research has found that the novel coronavirus can travel more than 25 feet and remain viable in air for up to three hours, but only in tightly confined laboratory conditions. With any ventilation at all, i.e. almost any outdoor environment, expelled virus is scattered almost immediately, reducing concentrations to below transmission levels.
Public confusion, even skepticism, regarding masks is not entirely the fault of the public. After first insisting that masks were not necessary, U.S. health officials did a sudden about-face, urging the wearing of virtually any kind of mask when in public (without bothering to note that masks are unnecessary outside).
On Aug. 7, a group of researchers at Duke University published a clever study that used lasers to count droplets emerging from the mouths of people wearing 14 different types of mask and no mask at all, demonstrating that al masks are not equal.
According to the study, N95 masks used by hospital workers provide the best protection for both the wearer and those around them (excepting those with an exhalation valve), followed by surgical masks and fabric masks of at least three layers. Meanwhile, droplets expelled through a single-layer cloth mask (think neck gaiters, bandanas and knitted masks) were reduced in size, making them more likely to remain airborne for longer, rather than falling to the ground.
“There’s a lot of controversy and people say, ‘Well, masks don’t do anything.’ Well, the answer is some don’t, but most do,” one of the study’s co-authors, Warren S. Warren, professor of physics, chemistry, radiology and biomedical engineering at Duke, told the Washington Post. “If you can see through it when you put it up to a light and you can blow through it easily, it probably is not protecting anybody.”
Cynics might take this as evidence that scientists are just messing with us, but it’s precisely the opposite. Called upon for advice early in the pandemic, scientists offered their best judgment in the absence of clear data, but science didn’t stop there. Following the scientific method, the Duke researchers devised an experiment, resulting in data that now puts us all on firmer ground.
- In enclosed spaces or a crowd, always wear an N95, surgical or mask of at least three cloth layers. Thinner, more convenient masks may make things worse.
- There is no need to wear a mask well-ventilated, outdoor spaces. It’s advisable to maintain physical distance from others and definitely don’t join a crowd.
- Go to the beach! A beach — or park, trail or forest — is as safe a place as you can be.