According to Cambridge University scientists, when a person coughs without a mask, infectious particles can travel beyond two meters.
The study tested ten scenarios of a person coughing using computer simulations. It was found that each cough emits a different number of particles.
According to the models, most larger droplets will fall on nearby surfaces, but how far and quickly smaller droplets travel varies. In the absence of masks, a person with COVID-19 could transmit the disease to another person at a two-metre distance.
According to the CDC, people can catch COVID-19 from a variety of sources, from direct contact to the mouth, nose or eyes, from splashes or from dirty hands.
The number of particles can be very different even if the number of droplets stays the same.
He said that people should wear masks in indoor spaces such as offices, classrooms, and shops.
The MIT found that six feet was not enough to stop airborne transmission of coronaviruses indoors.
Bryan Bzdek, a research fellow at the Bristol Aerosol Research Centre at the University of Bristol, told Insider at the time that physical distance reduces exposure to the largest droplets, which travel like cannonballs and settle on the ground quickly.
The concentration of smaller aerosol droplets is always highest near the person's mouth and nose, which helps reduce exposure.
In May, the CDC said that if you catch COVID-19 by inhaling infectious particles further than six feet, you need to reduce your exposure to less than 15 minutes.
The researchers at Cambridge encouraged the use of masks.
They said that the vaccine, masks and ventilation are vital for containing the virus.
