Japanese researchers said on Wednesday that low concentrations of ozone can neutralise coronavirus particles, potentially providing a way for hospitals to disinfect examination rooms and waiting areas.
Scientists at Fujita Health University told a news conference they had proven that ozone gas in concentrations of 0.05 to 0.1 parts per million (ppm), levels considered harmless to humans, could kill the virus.
The experiment used an ozone generator in a sealed chamber with a sample of coronavirus. The potency of the virus declined by more than 90% when subjected to low level ozone for 10 hours.
"Transmission of the novel coronavirus may be reduced by continuous, low-concentration ozone treatment, even in environments where people are present, using this kind of system," said lead researcher Takayuki Murata.
"We found it to be particularly effective in high-humidity conditions."
Ozone, a type of oxygen molecule, is known to inactivate many pathogens, and previously experiments have shown that high concentrations, between 1-6 ppm, were effective against the coronavirus but potentially toxic to humans.
A recent study at the Georgia Institute of Technology showed that ozone may be effective in disinfecting gowns, goggles and other medical protective equipment.
Fujita Medical University Hospital, in Aichi prefecture central Japan, has installed ozone generators to reduce infection in waiting areas and patient rooms.
The university has also performed a clinical trial of Fujifilm Holdings Corp's Avigan drug on Covid-19 patients.