First of all, let’s start with a little more information on types of UV light and the differences between the UV light that tans our skin and the type that is being touted to kill germs.
If you look at your bottle of sunscreen you will see information about protection from UV-A and UV-B sun rays. UV stands for ultraviolet, and the electromagnetic spectrum of ultraviolet radiation is divided into nanometers representing the wavelengths–UV-A (400 – 315 nm) and UV-B (315 – 280 nm). This is the range of exposure we get from a day at the beach or tanning beds. UV-C is the type of ray from the sun that has the shortest wavelength and is also almost completely blocked by our atmosphere before it gets to us.
Artificial UV-C Has Been Used for Years
For decades artificially-produced UV-C light has been used to kill germs and bacteria in medical settings, labs, and water treatment plants. Originally mercury-vapor lamps were used, but with the advancement of LED technology, and now the coronavirus, UV-C products are for sale everywhere. There is wand-style, soft-sided lunch box types, and some the size of a large microwave oven; that all promise to make fabrics, surfaces, your glasses, keys, phone, make-up brushes, and pacifiers, germ-free.
A Magic Wand?
Sorry, maybe not. These devices claim to kill 99.9 percent of germs, bacteria, and viruses, and in seconds or minutes. The US Food and Drug Administration states, “UV-C radiation has been shown to destroy the outer protein coating of the SARS-Coronavirus, which is a different virus from the current SARS-CoV-2 virus. UV-C radiation may also be effective in inactivating the SARS-CoV-2 virus (COVID-19.)” I added the italics to this statement because in this case, these words matter when considering your health and safety. Currently, there is limited published data about the wavelength, dose, and duration of UV-C radiation required to inactivate the SARS-CoV-2 virus.” So, we really are not sure if these products work as advertised. In the current situation, if you’re spending your hard-earned money, having more information about what works and what doesn’t is important.
There are many products on the market that probably do not do what their sales hype promises, and consumers have no way to know if they are getting the correct wavelength of light delivered in the right way. There are only a few studies on exposure to humans under normal conditions of use. UV-C, like the other wavelengths of ultraviolet light, is considered to be carcinogenic to humans, but there is not enough data to fully assess the risk of exposure from UV-C lamps.
From the FDA:
Risks: UV-C lamps used for disinfection purposes may pose potential health and safety risks depending on the UV-C wavelength, dose, and duration of radiation exposure. The risk may increase if the unit is not installed properly or used by untrained individuals.
- Direct exposure of skin and eyes to UV-C radiation from some UV-C lamps may cause painful eye injury and burn-like skin reactions. Never look directly at a UV-C lamp source, even briefly. If you have experienced an injury associated with using a UV-C lamp, we encourage you to report it to the FDA.
- Some UV-C lamps generate ozone. Ozone inhalation can be irritating to the airway.
- UV-C can degrade certain materials, such as plastic, polymers, and dyed textile.
- Some UV-C lamps contain mercury. Because mercury is toxic even in small amounts, extreme caution is needed in cleaning a lamp that has broken and in disposing of the lamp.
Effectiveness: The effectiveness of UV-C lamps in inactivating the SARS-CoV-2 virus is unknown because there is limited published data about the wavelength, dose, and duration of UV-C radiation required to inactivate the SARS-CoV-2 virus. It is important to recognize that, generally, UV-C cannot inactivate a virus or bacterium if it is not directly exposed to UV-C. In other words, the virus or bacterium will not be inactivated if it is covered by dust or soil, embedded in porous surface or on the underside of a surface.
Consider Leaving it to the Experts
“Beware of false claims that say these products are effective or are safe for use on humans,” says Jung-Tsung Shen, an engineer and physicist at Washington University in St. Louis. “Right now, this is a gray market without regulations. There have been no rigorous scientific experiments and tests for the effectiveness of these devices.”
As much as we love a new gadget, hand washing, and cleaning items and surfaces with an alcohol solution with over 70% alcohol is still the safest (and least expensive) way to go. Also, considering that the odds of contracting the virus from surfaces is low, using UV-C light to kill the virus in the air is a hot and controversial topic.
Research at Columbia University has demonstrated that 222-nm far-UV-C light efficiently kills airborne influenza virus and researchers are now exploring its effectiveness against airborne coronaviruses. Cleaning the air from inside air ducts may be the safest and best application of UV-C, while posing no danger to people inside the building. We know that the highest transmission rates are still indoors, person to person, and through the air.
Wear a Mask
In the meantime, wearing a mask with at least 3 layers is still the best way to reduce your risk of contracting and spreading the COVID-19 virus.
Be well and stay safe.