Wearing two masks delivers little additional benefit in blocking the viral spread of COVID-19 compared with one properly fitted mask, according to Japanese supercomputer simulations.
Using a single, good-fitting surgical-type mask, made of non-woven material, provides 85% effectiveness in blocking particles, Reuters reported. But adding a second polyurethane mask on top of the first one increased effectiveness to just 89%. And wearing two non-woven masks doesn't work, either, because air resistance within them forces air to leak out round the edges.
"The performance of double masking simply does not add up," wrote the researchers, led by Makoto Tsubokura.
"Researchers used the Fugaku supercomputer to model the flow of virus particles from people wearing different types and combinations of masks, according to a study released on Thursday by research giant Riken and Kobe University," Reuters wrote. "The Riken research team previously used the Fugaku supercomputer to model how humidity can affect viral contagion and the infection risks in trains, work spaces, and other environments."