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Air conditioners may raise COVID-19 risks, says disease expert

Jiji

As summer approaches, experts are raising the alarm that use of air conditioners to battle the heat may lead to heightened risks of COVID-19 infections.

The novel coronavirus is generally not transmitted through the air, instead being passed through droplets from coughs or sneezes, or by touching virus-contaminated objects. However, speaking with many people in enclosed spaces and in close proximity can lead to infection risks even without coughs or sneezes.

According to Masayuki Ishida, a doctor specializing in infectious diseases at Chikamori Hospital in the city of Kochi, large droplets usually fall to the ground quickly but smaller ones stay in the air for a longer period of time. The use of air conditioners can lead to tiny droplets that contain the coronavirus being carried on the flow of air, raising the risks of infection even for people who are some distance from infected individuals.

Ventilation is important to prevent such risks, but ordinary air conditioners for home use circulate air indoors and do not let new air in.

“It is desirable to have a change of air for five to 10 minutes every hour,” Ishida said. “Two windows facing each other should be opened to create a flow of air, but if there is only one window, an air circulator or fan should be placed on the opposite side to create a wind blowing toward the window.”

As for air purifiers, only high-performance models are considered effective in eliminating viruses.

“It is unclear whether the use of ordinary air purifiers is fully effective as a countermeasure against the new coronavirus,” said an official at the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan.

Air conditioning equipment maker Daikin Industries Ltd. has detailed ventilation methods on its website and is accepting telephone consultations.

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