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The Benefits and Drawbacks of Disinfecting Surfaces and Killing COVID-19 with UV Lights

A handy way to disinfect surfaces, killing COVID-19 particles and other germs, is to use ultraviolet light. Specifically, UVC light, which is the only type of ultraviolet light powerful enough to be germicidal. (There are three types of UV light, according to the World Health Organization: UVA, which is long-wavelength; UVB, medium-wavelength; and UVC, short-wavelength.) As with other forms of disinfecting, UVC use has its benefits and drawbacks.

Benefits:

You don’t have to touch the surfaces.

By running a handheld light over a surface, or illuminating surfaces from a static fixture, you can sanitize it without coming into contact with it.

It can be fast.

Depending on the intensity of the UVC light and the distance from the target, short work can be made of germs. Manufacturer American Ultraviolet states that “The average bacterium will be killed in ten seconds at a distance of six inches” using one of their products.

It can be convenient.

Given a steady source of electricity, blasting surfaces with light can be more convenient than constantly acquiring and burning through consumable cleaning supplies.

Drawbacks:

It requires line of sight.

Anything in shadow from a UVC light doesn’t get disinfected. Thus, while this photo of a bus in China being disinfected with UVC light looks great…

…any surface that the light is not directly falling on is not getting disinfected.

It can be slow.

American Ultraviolet states that “The inverse square law applies to germicidal ultraviolet as it does to light: the killing power decreases as the distance from the lamps increases.” While you can be sure of efficacy–“High intensities for a short period and low intensities for a long period are fundamentally equal in lethal action on bacteria”–depending on the distance and intensity of the light, the ten-second example they list above can get a lot longer.

It can be expensive.

Manufacturer Larson Electronics sells two different handheld UVC disinfecting lights, that each cost a whopping $1,070 and $1,258.

Unlike sanitizing wipes, they cannot also be used on the skin.

The WHO writes that “UV lamps should not be used to sterilize hands or other areas of skin as UV radiation can cause skin irritation.”

Some training will be required.

I suppose this isn’t different than training workers or yourself to use other, more traditional forms of cleaning products, but some instruction will be required. For example, the exact distances from surfaces and required exposure times for your application would need to be worked out, and that information would have to be understood and followed by the user.

All of that being said, the benefits of UVC disinfecting are likely to appeal to many.

Unsurprisingly given the times, affordable consumer-grade models are almost completely sold out on Amazon.