Even in non-pandemic times, public restrooms never really felt like the most hygienic spaces. Now, Chinese researchers have shown that flushing public toilets can release virus-rich aerosols that could easily be inhaled.
To carry out the study, researchers from Yangzhou University in China modeled the flow of particles when urinals are flushed using computational fluid dynamics. Understanding that urinal flushing mixes gasses with liquids, they found that 57 percent of the flush flies away from the urinal in an aerosolized form. What’s more, the mist showed a “violent climbing tendency,” according to one of the researchers, which saw it rise to thigh height in just 5.5 seconds. For comparison, the aerosol from a toilet flush takes 35 seconds to reach roughly the same height.
Considering that the current virus has been found in both stool and urine samples (although it’s unclear whether the infection can spread that way), the study certainly suggests that extra caution be taken in public restrooms.
“From our work, it can be inferred that urinal flushing indeed promotes the spread of bacteria and viruses,” said researcher Xiangdong Liu. “Wearing a mask should be mandatory within public restrooms during the pandemic, and anti-diffusion improvements are urgently needed to prevent the spread of COVID-19.”
One such improvement might be the use of more waterless urinals that don’t require flushing.
The study has been published in the peer-reviewed journal Physics of Fluids.