People spending a penny in public toilets should always wear a face mask to reduce the risk of getting coronavirus, scientists have warned.
A new study found that flushing urinals can release clouds of virus-laden particles within a speedy five seconds.
This is compared to a normal toilet at home which takes 35 seconds to spread.
Chinese scientists Yangzhou University simulated and tracked the movements of the air-borne bugs when urinals are flushed.
Their findings, published in the journal Physics of Fluids, clearly show public toilets can be "dangerous" places for potentially becoming infected from a virus during the pandemic.
Urinals are used more frequently within densely populated areas and researchers warned that particles will travel faster and farther, posing a "serious public health challenge."
The team said their findings underline how important it is to wear a mask within public places.
Other research has shown that both faeces and urine-based virus transmission is possible.
Researcher Dr Xiangdong Liu said: "We used a method of computational fluid dynamics to model the particle movement that occurs with the act of flushing.
"The specific models are the volume of fluids model and discrete phase model."
De Liu added: "The climbing speed is much faster than toilet flushing."
"From our work, it can be inferred that urinal flushing indeed promotes the spread of bacteria and viruses.
"Wearing a mask should be mandatory within public restrooms during the pandemic, and anti-diffusion improvements are urgently needed to prevent the spread of Covid-19."
