Six feet. As Covid-19 has torn through the world, that distance has come to define daily life. Six feet is how far we stand from other shoppers or the space we try to maintain while catching up with a friend.
It’s painfully clear that our world has been constructed for a reality that no longer exists. Crowded subway cars, packed restaurants, and bustling sidewalks all pose a threat every time someone nearby sneezes, talks, or even just breathes.
Eventually, architects and engineers will reconstruct the world around us to take into account the pandemic—and others that may follow. Temporary plexiglass barriers and markings on the floor may give way to designs that favor privacy and small groupings of people to limit the spread of pathogens. “You’re going to see a style where things look safe to reassure people,” says Aaron Betsky, director of Virginia Tech School of Architecture + Design. “We’re going to make things that reassure people that there’s not something hiding somewhere that’s going to come out and bite them or make them sick.”
Betsky suspects we may see a resurgence of the aerodynamic and streamlined design of the 1920s and ’30s, a time which brought us, among other things, hospital rooms with rounded corners, making them easier to clean. The reimagining of cities and architecture in the wake of pandemics has been going on for centuries. In the 1800s, after cholera killed tens of thousands of Parisians, Georges-Eugène Haussmann razed overcrowded medieval neighborhoods to make way for the wide avenues and parks we know today.
The trouble is that the science informing our decisions about how to redesign our public spaces is rudimentary at best. Studies in the early 20th century argued that infectious droplets fell within a few feet, in line with the 1-meter distance the World Health Organization recommends as safe today. But a 2003 study of SARS, a coronavirus closely related to the one that causes Covid-19, indicated that droplets can spread farther. It showed that SARS could be transmitted to others as far as 6 feet away from an infected person while traveling on an airplane. The Centers for Disease Control and Prevention recommends maintaining a distance of at least that—or “about two arms’ length”—from other people.
The latest thinking is that the disease spreads both via large droplets that fall to the ground and tiny airborne ones. “It’s a continuum,” says Lydia Bourouiba, an epidemiologist who studies fluid dynamics at MIT, whose recent work demonstrated that “turbulent gas clouds” can carry pathogens 27 feet. She was among 239 scientists who signed an open letter to the WHO urging the organization to consider airborne transmission of Covid-19 in its guidelines. The agency recently updated its advice to say the virus can be airborne in poorly ventilated, indoor spaces.
Variables such as temperature, humidity, and airflow can all affect how effective that 6-foot distance really is. Indoors, without a mask, 6 feet isn’t really all that safe, says Gabriel Isaacman-VanWertz, a scientist at Virginia Tech who studies the way particles change in the atmosphere.