Early in the pandemic, health officials insisted that Covid-19 spread through droplets—through coughs and sneezes. In the medical canon, that’s how most respiratory infections were thought to spread. 1/ wired.trib.al/PFGbUeR
Some researchers disagreed. Linsey Marr, an aerosol scientist at Virginia Tech, suspected the coronavirus could hang in the air, infecting anyone who breathed in enough of it. 📷:Matt Eich 2/ 
As evidence mounted that Covid was airborne, Marr and other scientists teamed up to try to convince the WHO and CDC to update their guidelines—to advise people to wear masks and improve ventilation. 3/
But the agencies were unmoved, even as people kept dying. Marr and others realized they were fighting over the definitions of words: What is an aerosol, and what is a droplet? 📷:Matt Eich 4/
The researchers discovered that the battle of words hinged on a basic error in the physics of droplets and aerosols. For decades, papers and textbooks repeated the mistake until everyone accepted it as fact. 5/
Now, these scientific detectives have aired the mistake. The WHO and the CDC have changed their guidelines. It came too late to prevent Covid from stealing untold numbers of lives. But it might help make the future a safer place. 6/ wired.trib.al/PFGbUeR
Hard-Hitting Reporting. Provocative stories that will forever change how you think. Your first year is only $10: wired.trib.al/f3r0g6N
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