Ultraviolet light deactivates viral particles, can reduce SARS-CoV-2 transmission

BARCELONA, Spain — While America is experiencing a resurgence in coronavirus cases in many states, plans to reopen have been rolled back in the hardest hit areas. For those hoping to return to the office or eat inside their favorite restaurant again, they’ll have to wait a bit longer. Of course, scientists and virologists say sharing spaces indoors with others poses a threat for spreading of SARS-CoV-2. Ultraviolet light is seen as one potential technology to help curb that threat. Now, a team of researchers at the Institute of Photonic Sciences in Barcelona confirms that UV-C light is an efficient tool for inactivating viral particles that spread in indoor spaces.

Over the course of a day in an office building or a school the virus can spread in one of two ways. Air droplets can be exhaled by an infected person and inhaled by a healthy person. Face masks are a good way of preventing the virus from being spread this way. Virus droplets can also land on surfaces and healthy people might touch these surfaces and get infected.

Virus transmission vs UV light
Pathways of viral infection in everyday life shown in a simplified scheme (top) and illustrated by pictorial descriptions of exposure to virus in everyday activities (bottom). Placement of UV-C light sources at ventilation systems and rooms not in use, without direct optical paths to humans, help reduce virus propagation. (Image sketches by Nacho Gaubert.)

The most common method of preventing the spread of a virus through surface-contact is disinfectant sprays and wipes. Yet even if people are vigilant about wiping down surfaces, viral particles can still be lurking in shared indoor spaces.

UV-C light and the coronavirus fight

UV-C light has been used for sterilization for more than 100 years. It’s commonly used to disinfect water and it has been shown to reduce the spread of airborne viruses. The research team believes that UV-C light sources, which emit light at a wavelength of 254 nanometers, should be used to reduce the spread of SARS-CoV-2.

The light sources are readily available in the form of fluorescent lamps, LEDs, and microcavity plasma devices — which are all quite affordable. The team of scientists think these light sources should be used in public spaces to inactivate virus particles when the public spaces are closed or not in use. The light can be spread through the ventilation system of public spaces when they are closed.

Researchers ran a cost-benefit analysis of adopting this technology. They find that an investment of a few billion dollars could help protect about one billion workers worldwide. That may sound like a pretty penny, but it’s the cost of keeping people virus-free.

The study is published in ACS NANO.

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