Thanks, Marve.. :-)

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As the world turns to opening their economies after the great coronavirus shutdown, several strategies are being explored to prevent a ‘second wave’ outbreak, beyond contact-tracking apps.

The first focus is high-risk, high-touch areas for disinfection, such as hospitals, delivery vans, grocery stores, mass transit systems, elevators, door handles, even cash.

In high concentration cities, light railway, mass transit systems and public buses are a particularly challenging area. Millions rely on such public infrastructure each day, and expensive, chemical based cleaning products may not be an efficient or a non-toxic way to clean public transport.

Ultra-Violet light
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Germ-Fighting Robots Take Over Local Hospital

Two UV-light-wielding virus fighting robots made by Xenex named WALL-E and Rosie deployed in ... [+] Boston Globe via Getty Images

In a well cited Scientific Reports article from 2018, far-UV light has been shown to kill over 95% of a virus like the current coronavirus.

Normal UV is dangerous to humans and can result in cancer or cataracts in the eyes if there is over exposure. Hence, extreme precaution needs to be taken using ultraviolet solutions.

However, a type of ultraviolet light called far-UV is less dangerous to human cells, and can be used for several minutes in controlled environments without humans to disable the virus. Far-UV light does not penetrate the outer cell layers of the skin or eye of humans, but can do so for the thinner fat layer in viruses, preventing them from multiplying.

This works because the virus has a thin outer membrane, that can be more easily broken apart by UV rays.

Installation in trains and buses
Buses Disinfected By Ultraviolet Light In Shanghai

A bus is being disinfected by ultraviolet light on March 4, 2020 in Shanghai, China. Visual China Group via Getty Images

Such UV light is easily available as tubes that can either be slotted into existing transit system light sockets or attached to a fleet of moving robots.

Autonomous UV-robot systems (which have more flexibility than fixed installations) are now being trailed in hospitals around the world, having seen measures adopted in China and South Korea as they prepared to re-open their economies.

With light railways and low floor buses, fleets of such robots can roll in, switch on, and spend several minutes decontaminating each carriage. This could be particularly useful at the end of the line for each train or bus, cutting cleaning times from 40 minutes to less than 5.
Buses Disinfected By Ultraviolet Light In Shanghai

UV trolleys deployed within buses in Shanghai can disinfect the bus within 5 minutes compared with ... [+] Visual China Group via Getty Images

It is challenging to clean a train mid-journey, so those exposed during the journey could still be at risk. However, this would be orders of magnitude lower risk than allowing trains to travel up and down the line several times a day with a contaminated surface.

In several high profile videos, buses in Shanghai went through decontamination tunnels each time they returned to their depot.