The Japanese supercomputer shows that doubling masks offer little help in preventing viral spread

TOKYO (Reuters) – Japanese supercomputer simulations showed that wearing two masks gave limited benefit in blocking viral spread compared to a properly fitted mask.

The results partially contradict recent recommendations from the U.S. Centers for Disease Control and Prevention (CDC) say two masks were better than one at reducing a person’s exposure to the coronavirus.

The researchers used the Fugaku supercomputer to model the flow of viral particles from people wearing different types and combinations of masks, according to a study published Thursday by research giant Riken and Kobe University.

Using a single surgical-type mask, made of non-woven material, was 85% effective in blocking particles when worn tightly around the nose and face. Adding a polyurethane mask on top increased the effectiveness to only 89%.

Wearing two non-woven masks is not helpful because air resistance builds up and causes leakage along the edges.

“The performance of double masking just doesn’t add up,” wrote the researchers, led by Makoto Tsubokura.

Overall, professional-grade N95 masks were the best at protecting against infection, followed by non-woven masks, cloth masks, and finally types of polyurethane, the study showed.

The Riken research team previously used the Fugaku supercomputer to model how humidity can affect viral contagion and infection risks in trains, workspaces and other environments.

As the COVID-19 outbreak progresses, scientific consensus has grown that the virus spreads through the air and masks are effective in controlling the infection.

Rocky Swift reporting; Lincoln Feast montage.