Lightbulb moment: ultraviolet rays found to kill coronavirus in less than 30 seconds

Researchers at Tel Aviv University believe bulbs could even be installed in air conditioning and water systems

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Ultraviolet-emitting LED lights can kill the coronavirus quickly and cheaply, according to a study led by researchers at Tel Aviv University in Israel.

Scientists said ultraviolet light-emitting diode bulbs (UV-LEDs) destroyed 99.9 per cent of the virus in less than 30 seconds.

The new findings, published in the Journal of Photochemistry and Photobiology, showed that the lights could be installed in air conditioning and water systems to help limit the spread of Covid-19 in a cost effective way.

The problem is that in order to disinfect a bus, train, sports hall or plane by chemical spraying, you need physical manpower

“The entire world is currently looking for effective solutions to disinfect the coronavirus," said Professor Hadas Mamane, head of the environmental engineering programme at the university and lead author of the study.

“The problem is that in order to disinfect a bus, train, sports hall or plane by chemical spraying, you need physical manpower, and in order for the spraying to be effective, you have to give the chemical time to act on the surface.

"Disinfection systems based on LED bulbs can be installed in the ventilation system and air conditioner, for example, and sterilise the air sucked in and then emitted into the room.”

In the study, researchers tested the optimal wavelength for killing the coronavirus using irradiation. They found that a length of 285 nanometers was almost as efficient in disinfecting the virus as a wavelength of 265 nanometers.

This result was significant because the cost of 285 nm LED bulbs is much lower than that of 265 nm bulbs. The former are also more readily available.

However, Prof Mamane did warn that it was dangerous to try to use ultraviolet radiation to disinfect surfaces inside the home.

She said it was important that people were not directly exposed to the light.

Ultraviolet radiation is often used to kill bacteria and viruses.

Earlier this year, Dubai Health Authority introduced eight robots that use ultraviolet light to kill germs in medical facilities.

The devices can complete an "exhaustive sterilisation" of a room in 15 minutes.

Lights from UV lamps shine at 360 degrees and the robot covers each room several times before moving on.

In September, St Pancras railway station in London enlisted an army of UV-emitting robots to combat the spread of germs.

The UV technology means the robots can cover large areas of ground without the need for chemical disinfectant.

St Pancras International is London's ninth busiest station and home to the Eurostar which takes travellers to Paris, Brussels and Amsterdam.