By Rocky Swift
TOKYO, Oct 22 (Reuters) - Japanese researchers showed that
masks can offer protection from airborne coronavirus particles,
but even professional-grade coverings can't eliminate contagion
risk entirely.
Scientists at the University of Tokyo built a secure chamber
with mannequin heads facing each other. One head, fitted with a
nebulizer, simulated coughing and expelled actual coronavirus
particles. The other mimicked natural breathing, with a
collection chamber for viruses coming through the airway.
A cotton mask reduced viral uptake by the receiver head by
up to 40% compared to no mask. An N95 mask, used by medical
professionals, blocked up to 90%. However, even when the N95 was
fitted to the face with tape, some virus particles still sneaked
in.
When a mask was attached to the coughing head, cotton and
surgical masks blocked more than 50% of the virus transmission.
"There was a synergistic effect when both the virus receiver
and virus spreader wore masks," the researchers wrote in a study
published on Wednesday.
There has been a growing consensus among health experts that
the COVID-19 virus can be spread through the air. The U.S.
Centers for Disease Control and Prevention (CDC) revised its
guidance this month to say the pathogen can linger in the air
for hours.
A separate team of Japanese researchers used supercomputer
simulations to show that humidity can have a significant effect
on the airborne dispersion of virus particles.
(Reporting by Rocky Swift; Editing by Simon Cameron-Moore)