23 Oct, 2020
JERUSALEM WEATHER

No one has been jumping for joy over the current pandemic, but some people – for religious or family reasons – have been dancing and leaping into the air at weddings and other social or other celebrations. They should beware, according to Prof. David Katoshevski of the unit of environmental engineering at Ben-Gurion University (BGU) of the Negev in Beersheba. He warns that particles and droplets that may contain the COVID-19 virus float in the air for longer when you dance or jump. 

A device that measures the concentration of particles 

Katoshevski has been involved in the field of particle and drop dynamics in various systems – including spray/aerosol emitted from the respiratory system — for about three decades. As part of his research, he examined the distance that droplets emitted from the airways can cover and the length of time they stay in the air. 

 

Using a device that measures the concentration of particles in the air up to 10 microns (particles up to one hundred millimeters in size) that are capable of penetrating the respiratory system, he was joined by doctoral student Hamdi Abu Zaid and postdoctoral fellow Victor Molten to test the concentration of particles suspended in the air during dancing and jumping. 

Like a plane that takes off and carries air with it

They found that during an upward motion, dancers and jumpers drag with them the adjacent air and push microscopic particles upward; this extends their time in the air. “Like a plane that takes off and carries air with it, dancers and jumpers cause particles to rise, even though eventually they fall to the ground. When the person releases spray from his nose and mouth, the particles interact with each other and remain there due to the special flow field created. 

 

“If someone is infected with the COVID-19 virus, he emits a spray that will reach people who are dancing or jumping with him, and they are exposed for a long time,” the Technion scientist said.

For now, not a time to dance!

When the device was placed in the lab before the jumps, the values ​​(in micrograms per cubic meter) were significantly lower compared to testing during movement and jumps. “I wanted to show the public what concentration of particles are in the air while jumping and dancing. Since you don’t see them, it is difficult to realize that they are there. Thus celebrations, including during the upcoming Jewish festivals of Succot and Simhat Torah in which dancing are tradition, can be very risky, he concluded.