Droplets from the mouths of people who are talking loudly can linger in the air for up to 14 minutes before disappearing, a new study reveals.
The findings, which were published in the Proceedings of the National Academy of Sciences, could have a big impact on our understanding of COVID-19 and its transmission.
Public health officials know that SARS-CoV-2 and other respiratory viruses are transmitted via direct contact and when the virus is present in droplets released when someone coughs or sneezes.
Someone's speech also releases oral fluid droplets into the air, so researchers wanted to investigate how many were produced and how long they remain airborne.
The research team asked people to repeat phrases and harnessed the power of so-called sensitive lasers to visualize how the droplets moved in a stable environment. They estimate that a single minute of loud speaking generates at least 1,000 virus-containing droplets.
Some patients produce a much larger amount of the virus than average, however, which could push the number of virus-containing droplets “to well over 100,000 per minute of speaking,” the researchers write in their paper. Their findings indicate that the droplets stay airborne for longer than eight minutes, and sometimes as long as 14 minutes.
One note of caution: The tightly-controlled study did not examine or measure the types of temperature change or air circulation that you would find in almost any real-world environment.
Experts believe the study indicates the need for widespread adherence to wearing masks in public as a way to prevent COVID-19 transmission.
As of Thursday afternoon, there were more than 1.4 million infections and at least 84,985 deaths from coronavirus in the United States.