Using a public toilet? Mask up!

Think you do not have to worry about COVID-19 when using a public toilet? A team of researchers from Yangzhou University in China recently reported that flushing public restrooms could release clouds of virus-laden aerosols for you to potentially inhale.

If that is not enough, they have, after performing additional computer simulations, concluded that flushing urinals do the same. In Physics of liquids, the group shares their work with simulating and tracking virus-laden particle motions as urinals are played.

The work of researchers clearly shows that public toilets can be dangerous places for potentially being infected by a virus, especially during the COVID-19 pandemic. Other work has shown that both fecal and urine-based virus transmission is possible.

“To do this, we used a method for calculating fluid dynamics to model the particle motion that occurs with the action of spills,” Xiangdong Liu said. “The specific models are the fluid model volume and discrete phase model.”

Flushing a urinal, just like flushing a toilet, involves an interaction between gas and liquid interfaces. The result of the play causes a large dispersal of aerosol particles from the urine, which the researchers simulated and followed.

What the simulations reveal is disturbing. The flow of the small particles extinct by flushing a urinal “manifests an external type of spread, with more than 57% of the particles leaving the urinary tract,” Liu said.

But that’s not all. When men use urinals in a public toilet, these small particles can reach their thigh within 5.5 seconds compared to the toilet flush, which takes 35 seconds to reach slightly higher. Particles from urinals, however, “show a more violent climbing tendency,” Liu said. “The cooling speed is much faster than toilet flushes.”

Urinals are more commonly used in densely populated areas, and the researchers indicate that particles will travel faster and farther, posing a serious public health challenge.

This work underscores the importance of wearing a mask in public places, but especially in toilets.

“From our work it can be deduced that the urination flush actually promotes the spread of bacteria and viruses,” says Liu. “Wearing a mask should be mandatory in public restrooms during the pandemic, and anti-proliferation improvements are urgently needed to prevent the spread of COVID-19.”