Why it is better to keep the mask on when using public toilets (study)

Masked in the street, masked at the market, masked at work, and...masked in the toilet! Although it's tempting to want to take off your mask in the toilet to "breathe a little", a study suggests that it's rather a bad idea, at least when it comes to public toilets, and especially their urinals .

Researchers from the University of Yangzhou, in China, report indeed having observed that the flushing of public toilets can release and diffuse aerosols loaded with viruses which one is then likely to inhale. And so would flushing urinals.

In their study, published on August 18 in the specialized journal Physics of Fluids of the American Institute of Physics, the researchers detail their work of simulating and monitoring the movements of particles carrying the virus during toilet flushing.

In recent months, several studies have highlighted a probable contamination of faeces, suggesting a danger of transmission of the coronavirus in toilets. In addition, traces of Sars-CoV-2 are observed in wastewater, which is even turns out to be a good indicator of epidemic recovery.

Flushing a urinal, like flushing a toilet, involves an interaction between gas (ambient air) and liquid (water) interfaces. The result of flushing causes a wide dispersion of aerosol particles from the urinal, which the researchers simulated and tracked. And the verdict is quite concerning since the trajectory of tiny particles ejected by flushing a urinal "manifests with an external mode of spread, with more than 57% of the particles moving away from the urinal," Xiangdong Liu said. , co-author of the study.

Worse, the study reveals that the tiny particles ejected when flushing a urinal can reach the thigh of the man who uses it (at about 0.84 meters) in just 5.5 seconds. The same aerosols ejected by a toilet flush take 35 seconds to arrive a little higher, at 0.93 meters. This gives the toilet user a little more time to get away from the bowl. “The rise rate [of aerosols ejected by urinal flushing] is much faster than the toilet flush,” the researchers lament.

The face protection mask therefore seems more than recommended to filter these aerosols and avoid potential contamination, whether by the current coronavirus or by other viruses, responsible for the flu or even gastroenteritis.

Source: Eurekalert