Online tool helps you calculate risk of catching COVID-19 when gathering indoors

BOSTON — Since the start of the pandemic, the Centers for Disease Control and public health officials have been advising people to stay at least 6 feet away from others to prevent the spread of the coronavirus.

It’s guidance many have lived by but two MIT researchers say it’s dangerous and overly simplistic. They’ve developed a mathematical model they say is a better way to calculate risk level.

Because the equation is complex, the researchers developed an online tool where you can determine how long you will be safe in a room with someone who is positive for COVID-19 based on room type, size and even the ventilation and filtration system.

Say you just enjoyed a Thanksgiving dinner in a typical 20 by 20-foot room with a group of 10 people. No one was wearing a mask while eating, people talked normally (there was no singing), and the air was average humidity. Based on the model, it would be safe to be in the room for about 18 minutes. Adding coarse cotton masks would add two more minutes of safe exposure time, and opening windows to allow airflow would add another six minutes. Using surgical masks would increase the time to about two hours, according to the tool.

The researchers say the tool shows wearing masks correctly helps prevent the risk of transmission and increases the time you can gather with someone who has the virus and not catch it.

You can check out the tool here.

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