Ventilation Works

Image of open windows with sunlight streaming in

By Caitlin McCabe

Key to Preventing Covid-19 Indoors: Ventilation

Add this to the Covid-19 prevention toolbox: strong ventilation.

After urging steps like handwashing, masking and social distancing, researchers say proper ventilation indoors should join the list of necessary measures. Health scientists and mechanical engineers have started issuing recommendations to schools and businesses that wish to reopen for how often indoor air needs to be replaced, as well as guidelines for the fans, filters and other equipment needed to meet the goals.

“We didn’t focus on it enough initially,” said Abraar Karan, a doctor at Brigham and Women’s Hospital in Boston who treated Covid-19 patients. “We told everyone to stay home. We weren’t thinking about people congregating in public spaces.”

Driving the thinking is mounting evidence that the new coronavirus is transmitted through the air among people with prolonged exposure to the pathogen. Especially troublesome, epidemiologists and other scientists say, is evidence from numerous indoor outbreaks suggesting the virus’s ability to spread to others even when close contact is avoided.

The precise role that airborne transmission plays is still being debated by parts of the scientific community. Yet proponents of aerosol transmission say the evidence so far argues for the need to keep clean air flowing in indoor spaces where people gather.

Reopening schools and businesses should upgrade air systems, open windows.

Originally published on wsj.com September 1, 2020