Masks block coronavirus transmission, but not completely: Researchers

TOKYO: Scientists at the University of Tokyo have shown that though masks can provide protection against airborne coronavirus particles, even professional-grade coverings cannot eliminate contagion risk entirely. The researchers set up a secure chamber with mannequin heads facing each other. One of the heads was fitted with a nebulizer, simulated coughing and expelled actual coronavirus particles. The other mannequin head mimicked natural breathing with a collection chamber for viruses coming through the airway.

According to the results of the research, cotton masks reduced virus intake by the receiver head by about 40 per cent as compared to when the head did not wear a face mask. An N95 mask, used by medical professional, blocked upto 90 per cent of the virus particles. However, even when the scientists taped the N95 mask to the receiver head, some particles managed to get through. On the other hand, when a cotton or surgical mask was attached to the coughing head, virus transmission was reduced by over 50 per cent.

The researchers wrote in a study published on Wednesday, October 21, that a drastic decrease in virus transmission was noted when both the coughing and the receiver head wore masks. This comes when there is a growing concern among the scientific community that the coronavirus particles can spread through the air. The United States Centre for Disease Control and Prevention revised its guidelines this month and said that the coronavirus particles can remain suspended in the air for hours. 

A separate team of Japanese researchers used supercomputer simulations to show that humidity can have a significant effect on airborne dispersion of virus particles.