We’re arguably spending more time indoors than ever during the coronavirus pandemic. And with summer coming, we’re likely going to seek reprieve from the heat with air conditioning and fans while we’re in the confines of our walls.
So does all this put us at a higher risk for contracting COVID-19? What’s the deal with ventilation, and why is it so important? And what’s the risk difference between being outside compared to being inside?
Here’s what you should know:
The virus does spread more easily indoors.
The virus is more easily transmitted when you’re in closed areas, where there’s less ventilation or room for airflow. This is especially true for small spaces, like elevators.
“In such a tightly enclosed space without vigorous air movement for a short period of time, I’m afraid you might be exposed,” William Schaffner, a professor of infectious diseases at Vanderbilt University, told Business Insider.
Some evidence suggests sunlight may also be useful, but more research needs to be done. A study in The Journal of Infectious Diseases also showed that 90% of coronavirus particles deactivated within 10 minutes when exposed to UV rays from sunlight, according to a report from HuffPost UK. (This isn’t to be confused with temperature or warmth from the sun, which doesn’t have an effect, according to the World Health Organization. And you shouldn’t just assume that the sun will disinfect everything and make you safe.)
Health experts recommend people get outdoors when they can as a way to improve their physical and mental health, especially during a time that’s incredibly taxing on the mind and body. Just avoid group activities, like team sports, crowded playgrounds, etc. Walking, running and biking are all good ways to reap the benefits while still staying pretty safe.
Air conditioning or poor ventilation inside can theoretically spread coronavirus ...
Many people freaked out when a study of an air-conditioned restaurant in Guangzhou, China, found coronavirus spread to separate families eating in the restaurant. Each group was sitting near the air conditioner, and the direction of the airflow seemed to correspond with who got sick. Approximately 10 patrons became ill.
This can happen in more confined spaces, including your home. Indoor circulation of the virus typically occurs if you’re in range of the respiratory droplets a person expels into the air when they sneeze, cough or even just talk. These respiratory droplets are often “heavy,” meaning they can float in the air for up to a few feet before they fall to the ground.
As Mount Sinai Health System notes, “if someone in the house who is infected with the virus is coughing and sneezing and not being careful, then tiny virus particles in respiratory droplets could be circulated in the air. Anything that moves air currents around the room can spread these droplets, whether it is an air conditioning system, a window-mounted AC unit, a forced heating system, or even a fan.”
The virus may also be “aerosolized,” meaning tiny, lighter-weight particles of the virus can mix into the air with dust and dirt and spread around through the air ― and potentially through an AC system ― rather than falling to the ground pretty quickly because of their size.
A July report in the National Review also found that while evidence on AC and coronavirus is still mixed, there is some data that suggests an indoor cooling system could play a role in virus transmission.
In a piece for The Harvard Gazette, Edward Nardell, a professor of environmental health and of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health, pointed to Southern states in the U.S. as an example. A host of factors have played a role in the rise in cases in states like Florida and Texas, like mass reopenings and a lack of mask-wearing. However, Nardell also said that the hot weather luring more people to stay inside in air-conditioned spaces could be an additional contributor.
“The states that, in June, are already using a lot of air conditioning because of high temperatures are also the places where there’s been greater increases in spread of COVID-19, suggesting more time indoors as temperatures rise,” Nardell said.
“As people go indoors in hot weather and the rebreathed air fraction goes up, the risk of infection is quite dramatic,” he continued.
... but that risk can be easily mitigated by following recommended guidelines.
Experts stress that all of this shouldn’t cause panic. If COVID-19 was more airborne, we’d likely see higher rates of infection than we already do, infectious disease experts have told HuffPost.
Also, most important, your risk of catching the virus indoors can be lowered if you take some precautions.
Experts say that opening windows can help flush out virus particles and keep the air more free-flowing. Opening blinds and shades may also help your mission to reduce transmission. And if you have control over your AC, make sure your filtration is in top shape.
“One thing you can do if you are a homeowner and have a forced-air heating and cooling system is to ensure that the air filter in your unit is replaced according to the filter instructions .... Some filters are designed to remove particles such as respiratory droplets,” according to Mount Sinai. (Your indoor air quality is also important to your health, regardless of the coronavirus.)
Additionally, your proximity to an infected person matters. This is why social distancing is so important, whether you’re out on your daily walk, at the grocery store or taking care of a sick person at home.
The closer you are to someone who is contagious, the more likely you are to come in contact with respiratory droplets that can make you ill. Experts recommend keeping 6 to 8 feet of space between you and people who are not in your household (even without feeling sick, many people can still be coronavirus carriers).
Your risk of contracting the illness ― whether you’re inside or outside ― is lower overall if you follow the hygienic guidance put out by your local health officials and the federal Centers for Disease Control and Prevention.
That includes covering your mouth when you sneeze or cough, washing your hands and avoiding touching your face. Make sure to wipe down all high-touch surfaces, like doorknobs, countertops and handles.
And finally, wear a mask when you go outside if you live in an area where it’s required or recommended that you do so. Sure, it’s annoying ― but it’s also worth it. It can better protect you and others from those viral droplets.
Taking care of yourself ― even if it feels like an overreaction ― is the best way to control the spread.
This story has been updated to include more information that’s now known about indoor and outdoor spread.
Experts are still learning about the novel coronavirus. The information in this story is what was known or available as of press time, but its possible guidance around COVID-19 could change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.
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