Unsettling 3D simulations have underlined the risk of catching coronavirus on public transport, and why capacity on trains and buses have been slashed in NSW.
An infected passenger talking on public transport can spray and coat others with microscopic droplets which can transmit the deadly virus, University of Oregon research found.
Graphic visualisations show just how easily coronavirus can spread and move through the air in confined spaces, like public transport, offices and restaurants.
A study has shown how the spread of the coronavirus can occur on public transport, with droplets moving through the air and infecting other passengers. (Hexagon)
The models underline why maintaining safe social distancing is so crucial, to stop the spread of COVID-19.
"If you are breathing and talking obviously droplets don't travel as far, but they can travel far enough to affect your friend sitting opposite you, or someone who's chatting to you," University of Leicester respiratory scientist Dr Julian Tang told the BBC.
"That's the key distance. How far do [infected droplets] have to travel to infect someone else?"
He said if you can smell alcohol or food on someone's breath, then you are inhaling what they are breathing out.
Dr Kevin Van Den Wymelenberg from the University of Oregon told the BBC the virus could spread further than many realise.
"It's really impossible to completely eliminate risk," he said.
"But what we showed was a concept for how you could reduce transmission.
"The good news is that there are things you can do to make safer spaces."
His team's modelling of a restaurant environment showed how an infected diner sitting at a table can infect many others.
Using an open window to bring fresh air into the restaurant moved droplets through the air in a less dangerous way than air conditioning, the research showed.
Other University of Oregon models showed how a carrier of the virus working inside a kitchen or office can easily contaminate a hard surface.
People who then touch that area can be exposed to the coronavirus. It is unknown how long COVID-19 can last on a hard surface.
The research underlines why Australian health experts have persistently instructed the public to avoid touching their faces.