crowded tokyo train

Space and ventilation beneficial in preventing spread of Covid-19, study shows

Image credit: Dreamstime

The world’s fastest supercomputer has modelled the spread of Covid-19 on Japanese commuter trains and found that proper ventilation and reduced passenger numbers would significantly lower the concentration of the virus in the air.

Such a proposal would involve major changes to the operation of Japan’s notoriously crammed trains – two of Tokyo’s train lines are in the top 10 most overcrowded in the world.

Lead researcher Makoto Tsubokura said that opening windows on commuter trains can increase the ventilation by two to three times, which should help to lower the concentration of microbes in the air.

In an open letter published on Monday, 239 scientists in 32 countries outlined evidence that they say shows floating virus particles can infect people who breathe them in.

They call for ventilation improvements in enclosed areas used by the public, alongside general avoidance of crowded spaces.

One of the co-authors, Waseda University professor Shin-ichi Tanabe, urged a continuation of Japan’s 3Cs campaign which recommends that people avoid ‘Closed spaces, Crowded places and Close-contact settings’.

Other findings from the supercomputer-led research recommended the installation of partitions in offices and classrooms, while in hospitals, beds should be surrounded by curtains that touch the ceiling.

The World Health Organisation (WHO) has now acknowledged that evidence is ‘emerging’ that the virus can be passed on through airborne transmission, but is yet to say that this is definitive.

Speaking at a daily briefing in Geneva, Benedetta Allegranzi, WHO’s technical lead for infection prevention and control, said: “The possibility of airborne transmission in public settings - especially in very specific conditions, crowded, closed, poorly ventilated settings that have been described, cannot be ruled out.

“However, the evidence needs to be gathered and interpreted and we continue to support this.”

The supercomputer used in the study, dubbed Fugaku, was developed by Japanese firms Fujitsu and Riken and is currently rated as the world’s fastest computer.

Based on ARM architecture, the computer is intended for use in applications such as drug discovery, personalised medicine and weather forecasts.

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