While the world panics over the spread of the Covid-19 viral disease little attention is being paid in the news media to a known way to kill the virus on surfaces. Exposure to UV-C light damages the DNA of almost all living things, including the novel corona virus. Here’s what a quick but thoughtful internet search reveals.
Be Safe
Exposure of human skin to UV-C light will burn you and eventually promote skin cancer. It can’t be used directly on people and lamps that generate UV-C should only be used by careful and cautious members of the public. Here’s what a supplier to the heating and air conditioning industry says in their blog, UV-C Lamps: Playing it Safe
“Light in the Ultraviolet-C (UV-C) spectrum has proven effective in killing virtually all known microorganisms, making it the ideal solution for cleaning HVAC cooling coils and decontaminating the upper air in public spaces such as schools and hospitals.
The potency of UV lamps, however, means that care must be taken when servicing these systems. Unlike some hazards, exposure to ultraviolet light does not offer a natural avoidance response (e.g. squinting eyes in bright sunlight) or a physical cue that protection is necessary (e.g., heat radiating from a hot pan). Furthermore, the physiological effects of UV-C exposure are delayed and can appear up to six hours later.
While damage from UV-C is temporary, the HVAC/R industry takes steps to safeguard service personnel from avoidable ultraviolet exposure and the consequences of its short-term or chronic effects.”
With precautions noted, perhaps this disinfectant method could be used more widely, both in homes and in public spaces. Before we go further, let’s look at what UV-C light actually is.
UV-C Explained
Back in February of 2017 the blog, Noticias de Salud, carried and article entitled “Scientific Opinion assessing health risks associated with UV-C radiation from lamps concludes that further research is needed”.
“UV-C is ultraviolet radiation in the wavelength range of 280 to 100 nanometres. Most people have heard of the dangers of UV-A and UV-B exposure from the sun or from sunbeds. UV-C is also produced by the sun, but it is the shortest of the ultraviolet wavelengths and is almost entirely filtered out by the atmosphere before reaching the earth’s surface. The shorter the wavelength, the more impact ultraviolet radiation could have on human health.
Artificially-produced UV-C has been used successfully as a germicide and bactericide for decades. It can kill or disable micro-organisms like bacteria, viruses, mold and mildew, and doesn’t require the use of chemicals like chlorine. It is cheaper and more energy efficient than other methods of disinfection, using very little energy. Due to these advantages, UV-C is being used for an increasing range of applications, including for disinfecting air systems, wastewater treatment plants and air-conditioning systems. It is also used in food and beverage industrial processes and in hospitals to sterilise instruments, work surfaces and the air.
Although most appliances are sealed systems there is now increasing use of devices where consumers may be directly exposed to UV-C radiation.”
So, we now know what UV-C light is, that it does kill viruses and that direct exposure to it should be avoided by humans and animals. How can it be used to quell the raising panic over Covid-19?
UV-C in Hospitals and Commercial Spaces
A March 4, 2020 post from CHINADAILY.COM.CN suggests how the technique can be used in hospitals. This particular article doesn’t indicate whether such equipment is in broad use in that country or not.

For airplanes, an American company, Dimer UVC Innovations, has developed a robot to use for disinfecting passenger cabins.

According to IEEE SPECTRUM, a technical engineering publication, the GermFalcon has not actually been tested on the virus that causes COVID-19 but the company is willing to try it out for free on selected airlines.
Whether this device is actually in production and what it might cost an airline didn’t show up in my search.
Using UV-C in the Home
Clearly, products for home disinfection are on the market.
Google search for UV-C
Buyers should beware of several potential issues. First, only some UV lamps produce UV-C wavelength light. UV-A and UV-B and plain UV won’t do the trick. Second, while the lamp bases are relatively inexpensive they don’t always come with a bulb. It’s the bulbs that are costly. Thirdly, consumers need to understand the risks of exposure to UV-C. While the supplier may include instructions for safe use the pictures I saw show devices with minimal or no shielding. I suspect nothing you want to stay alive should stay in a room with such a device on – that means no pets, no children. I have no idea what UV-C does to plants.
People are beginning to purchase UV-C lamps as cases of COVID-19 are announced. Hopefully they will be effective in preventing its spread. In addition, we need to be sure we don’t create a secondary crisis of UV-C exposure.