Is Some Fancy UV Light the Solution?

You may have heard that UV light kills the virus, and we even have a question on this topic where our response says that exposing yourself to UV light will not help and can be dangerous.

However: the whole thing doesn’t seem to be a total farce, as there is coverage now of attempts to use UV light to address viral spread in areas like subways. The New York Times has a somewhat positive take, while the BBC is decidedly more negative. What’s really going on?

For some background: ultraviolet (UV) light comes in three types, UV-A, UV-B, UV-C. Sunlight contains mostly UV-A and UV-B (B causes sunburn and skin cancer) and UV-C is mostly blocked by the atmosphere.

All three types of UV light can kill viruses by degrading their genetic material. UV-A and UV-B light do this fairly slowly. UV-C, however, is very effective at killing bacteria and viruses, even airborne viruses in droplets. So you might imagine you could just, say, insert UV-C lights in all offices and the virus would be zapped.

The problem is that UV-C light is also typically dangerous to humans and so is often not used while people are present. It can give you a nasty sunburn within seconds. As a result, this is not a great plan on its face.

However- and this is what people are excited about – a 2018 article in Nature showed that a particular wavelength of UV-C light (which they call “Far UV-C”) is deadly for viruses and safe for people. The article showed — in a lab, with a cool setup — that many bacteria and viruses can be killed by this wavelength of light. In principle, this means that lights which emit this particular UV-C wavelength could be used in public areas or doctors offices, etc, and kill viruses in the area.

The devil is, as always, in the details. This has been demonstrated in a lab, not in the world. There are many, many hurdles to producing the machinery and infrastructure to set this up. The lab experiment used aerosol droplets; if you in fact need to bring the virus close to the light, you might need a fan setup to blow everything around. Of course, then the virus is being blown around at people.

Bottom line: super cool science, sound reasoning, definitely will see on the Starship Enterprise. In the short run, many logistical hurdles to implement.