Medical experts are calling for wider use of face masks and better ventilation in crowded indoor areas amid growing concern COVID-19 can be transmitted via air particles.
ANU professor of global environmental health Sotiris Vardoulakis is among researchers who say the virus could be transmitted through aerosols that travel further and hang around longer than first thought.
"We initially thought the virus was transmitted through larger droplets - coughs and sneezes - which land on a surface, then we touch the surface then our [face] and get infected," Professor Vardoulakis said.
He said there was some evidence the virus could move through small particles called aerosols, exhaled by an infected person.
"We don't know how far these aerosols might potentially travel or how effective they are at causing infection," he said.
"It appears this would likely depend on the size of the respiratory droplets from the infected person and their speed, determined by things such as sneezing or coughing."
Professor Vardoulakis was among ANU academics who recently published the ongoing research,COVID-19 environmental transmission and preventive public health measures.
He said Australia should look to a broader take-up of face masks, including in coronavirus-free jurisdictions like the ACT, to minimise the potential risk of airborne transmission.
Ensuring indoor areas such as shopping centres and supermarkets were well-ventilated was also key, Professor Vardoulakis said.
"In the absence of conclusive evidence at the moment we think its important to make wider use of face masks and treat the virus as if it were transmitted by air," he said.
"This situation is evolving and our knowledge about the virus and its transmission is also evolving.
"We know this is probably happening to some extent, we don't know exactly to what extent."
Face masks are currently mandatory in Victoria and strongly recommended in NSW when physical distancing cannot be guaranteed.
Professor Vardoulakis argued there could be low-risk of community transmission in the ACT and residents should use masks in indoor spaces such as supermarkets and shopping centres.
The ACT government does not currently recommended the general public wear masks, but have advised the community to prepare.
Ventilation of indoors areas including aged care facilities, shopping centres and public transport would also reduce airborne transmission, Professor Vardoulakis said.
He said air conditioning and heating systems that recirculated air might increase the risk of infection, but noted HEPA filters and portable air cleaners could remove the dust and pollen particles that may carry the virus.
Natural ventilation, by opening a window or door, could also be effective Professor Vardoulakis said.
"We want to make sure we have good ventilation, so the air is not recirculated in enclosed spaces," he said.
"This dilutes any viral particles in the air, and reduces risk of infection."