The coronavirus pandemic continues to remain elusive, with new information coming in every day about the virus, and ways to prevent it.

Masks, face shields, and gloves have become the new normal, and people are playing with different ideas to protect themselves in a world where isolation is difficult, if not impossible.

Also read: Most homemade face masks block large cough droplets, even as single layer, says study

According to a simulation by a Japanese supercomputer, plastic face shields are totally ineffective at trapping aerosols, making it an inefficient tool against COVID-19.

Simulation of aerosol activity

The world’s fastest supercomputer, Fugaku undertook a simulation whereby it was found that almost 100 per cent of airborne droplets smaller than 5 micrometres were able to escape through plastic visors which have become a common sight now.

One millionth of a metre constitutes one micrometre. According to a government-backed research institute, about half of larger droplets over 50 micrometers were also able to escape into the air.

Besides hand washing and sanitisation, aerosol transmission and ventilation are important factors in the transmission of coronavirus.

Also read: If you’re caught here without a mask, you dig graves for COVID-19 victims

Face visors have become common as global economies reopen, with shops across all sectors reopening.

Makoto Tsubokura, team leader at Riken’s centre for computational science, said the simulation combined air flow with the reproduction of tens of thousand of droplets of different sizes, from under 1 micrometre to several hundred micrometres.

Not an alternative to masks

To ascertain the role of face shield’s protection against COVID-19, the simulation took into account air flow and production of thousands of droplets of varying sizes. 

Makoto Tsubokura, the team head at Riken’s centre for computational science told the Guardian that face shields should not be seen as an alternative to masks, and further added that the effectiveness of visors is lesser compared to face masks.

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“This is especially true for small droplets of less than 20 micrometres,” he told The Guardian.

Small particles were able to escape through the gap between the face shield and the face.

Earlier, Fugaku had found that face masks made out of non-woven fabric are more effective than cotton and polyester masks.