Covid-19, known to be spread by inhaling virus-laden aerosols, can linger in public toilets 10 times longer than other open spaces, according to an alarming study by researchers at the Indian Institutes of Technology-Bombay, pressing the need for good ventilation of interior spaces. The Covid-19 virus travels inside tiny microscopic droplets or aerosols ejected from our mouths when we speak, shout, sing, cough, or sneeze. It then floats in the air, where it can be inhaled and passed on to other people. But in indoor spaces, it tends to linger more in dead areas like communal toilets, corners of a room, or around furniture, increasing the risk of transmitting infection.
In a new study, published in the journal Physics of Fluids, the IIT-Bombay team explored how airflow can mitigate the transmission of Covid-19 indoors by taking inspiration from the flow of air around planes and engines. Researchers have found that the chances of infection are significantly higher in a dead zone.
“Surprisingly, they can be near a door or window, or right next to an air conditioner blowing in the air. You might expect these to be safe areas, but this is not the case, ”Krishnendu Sinha, IIT-Bombay professor, said in a statement.
In toilets – found in offices, restaurants, schools, airplanes, trains and other public spaces – the use of water has been found as a major source of aerosols, and computer simulations of the Air flows in public toilets showed infectious aerosols in dead areas can linger up to 10 times longer than the rest of the room, researchers said.
“Computer simulations show that air travels on winding roads, like a vortex,” added Vivek Kumar, co-author.
“Ideally, the air should be continuously exhausted from every part of the room and replaced with fresh air. This is not easy to do when the air is trapped in a dead zone,” he said. Explain.
Currently, ventilation design is often based on air changes per hour. Although these design calculations assume that the cool air reaches all corners of the room evenly, computer simulations and experiments in a real bathroom show that this does not happen, Sinha said.
“The air change per hour is not the same for all parts of the room. It can be 10 times lower for dead zones. To design ventilation systems that are more efficient against the virus, we need to place ducts and fans according to the air circulation. in the room. Blindly increasing the volume of air through existing ductwork will not solve the problem, ”he suggested.