Via Nature News & Comment: The snot-spattered experiments that show how far sneezes really spread. Click or tap through for the full article and a 3:47 video. Excerpt:
So, how do you get your research subjects to sneeze on cue?
“That's a question I get a lot,” says Lydia Bourouiba with an easy smile. The solution turns out to be surprisingly simple: just take a small, rod-shaped device, use it to tickle a subject's nostril for a few seconds, and — achoo!
For Bourouiba, a mathematician and fluid dynamicist, that sneeze is the pay-off. She and her team at the Massachusetts Institute of Technology (MIT) in Cambridge record the explosive aftermath in gross detail using one or sometimes two cameras running at thousands of frames per second. Played back in slow motion, the videos reveal a violent explosion of saliva and mucus spewing out of the mouth in sheets that break up into droplets, all suspended in a turbulent cloud.
The videos that Bourouiba has recorded in this way allow her to measure everything from the diameter of the droplets to their speed — data that help her to learn more about how these particles carry viruses and other pathogens to their next host.
She has shown that sneeze and cough particles can travel the length of most rooms and can even move upwards into ventilation shafts — suggesting that microbes in the droplets could potentially spread farther and over longer periods of time than current theories suggest.
Ultimately, says Bourouiba, her goal with this work is to ground epidemiology and public health in physics and mathematics. When trying to keep diseases from running rampant, she says, “we want to be giving recommendations that are based on science that has been tested in the lab”.
In practical terms, such insights could lead to maps showing the contamination risks in the vicinity of infected people, protective equipment optimized to shield hospital workers from specific kinds of germs, and better predictions of how diseases move through a population.