Air conditioning units should be turned off as they could recirculate same air in a room and promote the spread of COVID-19, reports by engineering experts have shown.
Air conditioners are broadly categorised into two types – ones that take in air from the outside and expel it and the ‘split units’, which recirculate the same air, Shaun Fitzgerald, a fellow at the Royal Academy of Engineering, told The Telegraph.
A document by the Chartered Institution of Building Service Engineers also noted that air conditioning units that do not have a “dedicated source of outside air supply into a room… could be responsible for recirculating and spreading airborne viral particles into the path of socially distanced users”.
Fitzgerald added that opening a window while having the air conditioning turned on may be the best way to reduce the risk.
“The recommended strategy now, if you have one of these split units, is to throw the window open and sacrifice your desire for a cold or cooler environment,” he said.
“If there is a modicum of wind, it will move the air around. If you can’t open a window, turn the unit off.”
Also, in June, Qingyan Chen, a mechanical engineering professor at Purdue University, had cited what happened on the Diamond Princess cruise ship, where 700 out of 3,000 passengers got sick.
“After quarantine, many people still got sick on the ship and I suspect that the air conditioning system could [have] played a role there,” Chen told Business Insider.
“Air conditioners will take air and re-circulate it through the room, and it’s through that mechanism that these coronavirus droplets can be transmitted.”
A major study that raised concerns about air-conditioning in the wake of the pandemic was published on April 2 about a restaurant in China.
Researchers linked nine coronavirus infections in Guangzhou to one 63-year-old woman, and most of the patients did not have any direct contact with her, but sat on neighbouring tables at a restaurant.
The report implied that air-conditioning can help spread the virus, but because the droplets did not seem to blow far, in a restaurant with 83 people, only 10 got sick.
Therefore, they concluded, the air conditioner was likely to have spread the virus further between the affected tables.
A recent study by the University of Oregon and the University of California found the best way to ensure proper ventilation to limit viral spread is to open a window.
However, experts are skeptical as to whether the coronavirus can be spread through floating droplets in the air, though the World Health Organisation (WHO) has acknowledged this is possible.
As of Sunday morning, more than 12 million COVID-19 cases with over 550,000 deaths had been recorded globally.

The Cable