A team of researchers from IIT-Bombay has found out that infectious aerosols can linger in the air up to 10 times longer in “dead zones” in enclosed spaces.
These dead zones include areas above washbasins in washrooms, behind doors, corners, and around the furniture. Slow air circulation in these zones can potentially be the source of Covid infection transmission, the report ‘Effects of Recirculation Zones on the Ventilation of a Public Washroom’ which was published on November 2, says.
“Ideally, air in a room should be continuously replaced with fresh air for proper ventilation, but it gets trapped in areas behind the door, in corners, around furniture or behind some obstacle. While windows, fans, air conditioners and exhaust fans keep most parts of a room properly ventilated, in these dead zones, the air gets trapped and keeps going in a circular motion. Technically these are called recirculation zones. These zones were identified using computer simulation for the study,” said professor Krishnendu Sinha from the Department of Aerospace Engineering at IIT-B.
Researchers have showcased the significance of proper ventilation in closed rooms to mitigate transmission of Covid-19 using computer simulation. “The ventilation systems are often designed keeping in mind the air changes per hour value. This is assuming every corner is getting fresh air, but our simulations have shown us that some corners do not get fresh air as quickly as other open parts. If infected people are using it, then it is important to pump in fresh air swiftly in these zones,” said Sinha. Chances of infection are significantly higher in these dead zones as infectious aerosols can linger up to 10 times longer as compared to other well-ventilated parts of the room, the team found.
The team has recommended using additional fans or ducts facing the dead zones to mitigate the spread of infection. Using fans can help ventilate the dead zones. In their experiment they found that keeping a washroom door partially open, facing the basin, could be helpful too.
Credits – Source – https://economictimes.indiatimes.com/industry/healthcare/biotech/healthcare/coronavirus-lingers-longer-in-public-areas-washrooms-with-dead-zones-iit-b-study/articleshow/87785860.cms