The study, which was conducted by researchers at the US National Institute of Diabetes and Digestive and Kidney Diseases and the University of Pennsylvania, used a laser to determine the number of respiratory droplets released through human speech. The researchers found that just one minute of loud speaking releases at least 1,000 droplets that can linger for as long as 14 minutes, possibly carrying the coronavirus.
“Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second,” the report concluded, adding that researchers’ observations confirmed “that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments.”
“This direct visualization demonstrates how normal speech generates airborne droplets that can remain suspended for tens of minutes or longer and are eminently capable of transmitting disease in confined spaces,” the authors wrote.
However, study did not directly involve the novel coronavirus or any other diseases. Rather, it looked at how many oral fluid droplets are released per second and how long they linger in the air. Researchers are still unsure whether COVID-19 can spread through aerosol droplets, and it is unclear whether the lingering droplets observed by the study could carry enough virus particles to infect someone.
“This study doesn’t directly test whether the virus can be transmitted by talking, but it builds a strong circumstantial case that droplets produced in a normal close conversation would be large enough and frequent enough to create a high risk of spreading SARS-CoV-2 [the virus that causes COVID-19] or any other respiratory virus between people who are not wearing face masks,” Benjamin Neuman, a virologist at Texas A&M University-Texarkana, who was not involved in the study, told the Washington Post about the report.
The study’s findings provide evidence that it may be beneficial to wear masks in public spaces, which is currently being recommended by the US Centers for Disease Control and Prevention (CDC).
