When masks are needed outdoors
If you stop having a long conversation with someone who isn't vaccinated, masks are recommended. Even outdoors, the longer and closer you stand, the greater the risk of breathing someone else's air. One of the few documented cases of outdoor transmission occurred at the start of the pandemic in China, when a 27-year-old man stopped to chat outside with a friend who had just returned from Wuhan, where the virus originated. Seven days later, he had his first symptoms of Covid-19.
April 22, 2021, 9:03 a.m. ET
And masks are still recommended if you are out in a crowd. Standing shoulder to shoulder with strangers during an outdoor concert or protest can increase the risk, especially for the unvaccinated.
Recently, when she was hiking without a mask, Dr. Marr, she still tried to keep her distance from large groups when the path was crowded.
"When I passed a solo hiker, it was none of my business," said Dr. Marr. “But when I passed a group of 10 hikers in a row, I continued to step off the path. The risk is still small, but at some point there might be enough people for the risk to be felt. "
When the risk is lowest outdoors
Take your dog for a walk, ride a bike, hike a trail, or have a picnic with members of your household or vaccinated friends. These are activities where the risk of virus exposure is negligible. In such situations, you can have a mask in your pocket in case you find yourself in a crowd or need to go into the house.
"I think it's a little too much to ask people to put the mask on when they're walking, jogging, or biking," said Dr. Muge Cevik, Clinical Lecturer in Infectious Diseases and Medical Virology at the University of St Andrews School of Medicine in Scotland, where outdoor masking was never required. "We are at a different stage of the pandemic. I think external masks should not have been prescribed at all. This is where the infection and transmission does not take place."
“Let me run, maskless. Mask in your pocket, "tweeted Dr. Nahid Bhadelia, an infectious disease physician and medical director of the Department of Specific Pathogens at Boston Medical Center. “Given the conservative opinion I've had all year, this should show how little the risk of transmission outdoors is in general with short-term contact – and even less after vaccination. Keep the masks with you when you are stationary in a crowd and going inside. "
To understand how low the risk of transmission is outdoors, researchers in Italy used mathematical models to calculate the time it would take a person to get infected outdoors in Milan. They envisioned a bleak scenario in which 10 percent of the population was infected with Covid-19. Their calculations showed that it takes an average of 31.5 days of continuous outdoor exposure for a person avoiding the crowds to inhale a dose of virus sufficient to transmit an infection.
"The result is that this risk in the outside air is negligible if crowds and direct human contact are avoided," said Daniele Contini, lead author of the study and aerosol scientist at the Institute of Atmospheric Sciences and Climate in Lecce, Italy.
Even with more infectious virus variants floating around, the physics of virus transmission in the open air has not changed and the risk of infection in the open air is still low, according to virus experts. Pay attention to the infection rates in your community. As the number of cases increases, the risk of encountering an infected person increases.
When outdoor fun moves indoors
Dr. Cevik notes that debates over outdoor masking and articles featuring photos of crowded beaches during the pandemic have created the false impression that parks and beaches are unsafe and distracted by the much higher risks of indoor transmission. Often times, it is the indoor activities associated with outdoor fun – like traveling without a mask on a subway or a car for hiking, or visiting a pub after being on the beach – that pose the greatest risk. "People grill outside, but then they spend time inside chatting in the kitchen," said Dr. Cevik.
The more people vaccinated, the easier it will be to decide whether to be maskless outdoors. While no vaccine offers 100 percent protection, the breakthrough infection rate has been exceptionally low. The U.S. Centers for Disease Control and Prevention recently reported just 5,800 breakthrough infection cases in 75 million people vaccinated. And the C.D.C. said vaccinated friends and family members can safely spend time together without masks.
However, it's okay to keep wearing your mask outdoors if that's what you prefer. After a year of pandemic precautions, people can find it difficult to adjust to less restrictive behaviors. Sarit A. Golub, professor of psychology at Hunter College, City University of New York, said it was important that both the media and public health officials share the reasons people can change certain behaviors, such as masking outdoors.
"In the months ahead, 'normal life' will be safer, but I worry that some people may not be willing or able to relax pandemic restrictions in any meaningful way," said Dr. Golub. "I worry that people have internalized the fear messages without understanding the reasons for certain behavioral recommendations, and therefore the reasons they can be changed if circumstances change."
Gregg Gonsalves, assistant professor of epidemiology at the Yale School of Public Health, said he recently dated a group of parents, including many vaccinated doctors, who met in a New Haven park to mark a child's first birthday to celebrate. "We're all just standing around, all masked, and then we said, 'When can we be outside and take off our masks? "Said Dr. Gonsalves." If people are vaccinated and you are outdoors, masks are probably unnecessary at this point. "
But dr. Gonsalves said he understands why some people may not be willing to give up their masks outdoors. "Some of that is Covid Hangover," he said. "We were so traumatized by all of this. I think we need to have a little compassion for the people who are having trouble letting go."
Illustrations by Eden Weingart