Recently, a Japanese supercomputer generated simulation demonstrated that plastic face shields are not sufficient in trapping respiratory aerosols suggesting that they are not effective at all in preventing the coronavirus spread. The simulation combined airflow and production of thousands of droplets of varying sizes to find the effectiveness of face shields in protection against COVID-19.
The world’s fastest supercomputer, Fugaku calculated that almost 100 per cent of airborne droplets which were less than 5 micrometres in size could escape the plastic visors. It is concerning as people working in the service sector often use plastic visors as protection.
Riken, a government-backed research institute said, “About half of larger droplets measuring 50 micrometres found their way into the air.”
Apart from hand-washing and sanitisation, aerosol transmission and ventilation are major contributors to the spread of coronavirus.
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. This is especially true for small droplets of less than 20 micrometres.”
It was found that small particles could escape through the hiatus between face and face shield.
Tsubokura advised people who could not wear masks due to medical reasons like any underlying respiratory problems to instead use face shields, provided they are outdoors or in properly ventilated indoor areas.
It was recently discovered by Fugaku that face masks made from non-woven fabric could more effectively block Covid-19 spread via airborne droplets in comparison to those masks which are made from cotton and polyester.