Scientists at Japanese Research Institute Riken and other entities used the supercomputer Fugaku to study how coronavirus droplets spread beyond.
A simulation shows that coughing while wearing a cotton mask reduced the spread of droplets by about 70 percent, while a non-woven mask was 80 percent effective.
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Researchers said although face shields can prevent the spread of large droplets, the preventative device is limited in blocking fine particles.
The study also showed how droplets spread when someone coughs repeatedly in an auditorium or concert hall.
The particles did not go very far when the subject wore a mask.
But, a person not wearing any face coverings transmitted droplets to the row in front.