The plumes of aerosols – which spread everywhere in the room, in the event of an open toilet – can transmit infectious diseases, such as Covid-19, influenza or norovirus.
It’s a study you’re likely to think about every time you go to the toilet. A recent study by researchers at the University of Colorado, published in the scientific journal Nature and relayed by The Conversation, shows what happens when you flush without first lowering the toilet lid.
Every time you flush the toilet, it releases tiny water droplets, called aerosol plumes, into the surrounding air, which can spread pathogens.
A speed of 2 meters per second
To carry out their study, scientists from the University of Colorado used high-power lasers placed in front of a basin to illuminate the aerosol plumes, in order to image and measure their positioning and movements.
“Even though we expected to see these particles, we were surprised by the force of the jet ejecting the particles from the bowl,” John Crimaldi, lead author of the study, told The Conversation.
While scientists have long known that flushing toilets release aerosol plumes into the air, it is their movements that this study sheds light on. The green light from the lasers reveals that they are traveling at a speed of 2 meters per second, rapidly carrying these particles up to 1.5 meters above the bowl.
Important vectors of human diseases
The droplets are first projected towards the ceiling and the wall behind the toilet. They then fall forward and into the rest of the room. If this study is interesting, it is because these particles are loaded with bacteria and viruses contained in the faeces.
“Aerosol particles containing pathogens are important vectors of human disease”, explains John Crimaldi.
According to the study, small particles that remain suspended in the air for a period of time can expose people to respiratory diseases such as influenza or Covid-19 through inhalation.
Larger particles that settle quickly on surfaces can spread intestinal diseases like norovirus through contact with hands and mouth.
Close the lid tightly
In addition, toilet water contaminated with these feces may have concentrations of pathogens that persist after dozens of flushes. So if the toilet is in the bathroom, the particles can end up on a towel or toothbrush.
While this study shows the projection and movement of the aerosol plume, it does not directly address how they can transmit disease and the associated risks.
In the meantime, the researchers therefore recommend closing the lid tightly before flushing.
Source: BFM TV