A newly released study confirms that sneezes and coughs stay airborne for longer distances than previously believed, according to a Massachusetts Institute of Technology press release.
The study, conducted at MIT, shows how a gas cloud is formed after some coughs or sneezes.
The gas cloud keeps potentially infectious droplets aloft over greater distances than previously believed, according to the release.
The study showed that the smaller droplets that emerge in a sneeze or cough may travel five to 200 times further than they would if those droplets moved as groups of unconnected particles.
The tendency of these droplets to stay airborne, resuspended by gas clouds, means that ventilations systems can be become more susceptible to transmitting potentially infectious particles than previously believed, according to John Bush, a professor of applied mathematics at MIT.
"When you cough or sneeze, you see the droplets, or feel them if someone sneezes on you," said Bush, co-author of a new paper on the subject, according to the release. "But you don't see the cloud, the invisible gas phase. The influence of this gas cloud is to extend the range of the individual droplets, particularly the small ones."
According to the study, the droplets 100 micrometers in diameter travel five times farther than previously believed.
Droplets 10 micrometers in diameter travel 200 times farther and those less than 50 micrometers in size tend to remain airborne long enough to reach ceiling ventilation units, according to the study.
"You can have ventilation contamination in a much more direct way than we would have expected originally," says Lydia Bourouiba, an assistant professor in MIT's Department of Civil and Environmental Engineering, and another co-author of the study, according to the release.