Friday, May 15, 2020

Experiment shows human speech generates droplets that linger in the air for more than 8 minutes

Public health authorities recommend wearing a face covering to prevent spreading droplets that could contain the coronavirus. (Sergio Moraes/Reuters)

By Joel Achenbach

Ordinary speech can emit small respiratory droplets that linger in the air for at least eight minutes and potentially much longer, according to a study published Wednesday that could help explain why infections of the coronavirus so often cluster in nursing homes, households, conferences, cruise ships and other confined spaces with limited air circulation.

The report, from researchers at the National Institute of Diabetes and Digestive and Kidney Diseases and the University of Pennsylvania, was published in the Proceedings of the National Academy of Sciences, a peer-reviewed journal. It is based on an experiment that used laser light to study the number of small respiratory droplets emitted through human speech.

The answer: a lot.

“Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second,” the report states.  Read more >>