Loud talking can leave coronavirus lingering in the air for much longer than previously thought, scientists say.
A US study claims that infected people can release thousands of droplets when speaking, which can then remain airborne for up to 14 minutes.
The findings, published in the Proceedings of the National Academy of Sciences, come after scientists used laser lights to study how oral spray travels.
As part of the study, a person was filmed saying the phrase "stay healthy" for 25 seconds in an enclosed space.
The location was then filmed for 80 minutes, to analyse how many particles remained in the air.
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Researchers at the National Institute of Diabetes and Digestive and Kidney Diseases in Maryland then studied the images, which showed that loud talkers can release thousands of fluid droplets per second.
This suggests that coronavirus can be spread through normal conversation, and not just coughs and sneezes.
"These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments," the authors said.
"It has long been recognised that respiratory viruses can be transmitted via droplets generated by coughing or sneezing.
"It is less widely known that normal speaking produces thousands of oral fluid droplets with a broad size distribution."
It comes as Brits are now advised to wear face masks on public transport and in enclosed spaces such as shops to slow the spread of Covid-19.
Earlier this week, Transport for London urged rail and bus passengers to cover their faces as some begin returning to work as per new lockdown rules.
The government has also advised face coverings in enclosed public spaces where you may be more likely to come into contact with people you do not normally meet, such as in shops.
Face coverings do not need to be worn outdoors, while exercising, in schools, in workplaces such as offices, and retail, or by those who may find them difficult to wear, such as children under two or primary aged children who cannot use them without assistance, or those who may have problems breathing whilst wearing a face covering.
The public is also being strongly urged not to purchase surgical masks or respirators, which are prioritised for healthcare workers.
