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Ultraviolet disinfection

Are they really working?

The rise of infection cases in recent months (due to COVID19) has led to a significant, yet predictable, increase in the sales of ultraviolet-based disinfection gadgets. The usefulness of Ultraviolet (UV) rays to disinfect (killing bacteria or deactivating viruses) has been known for more than 70 years.
UV-based disinfection is being commonly used in healthcare facilities; specifically, for disinfecting equipment. However, using a UV-based disinfecting handheld device requires a more thorough investigation and one cannot rely on the promotional information provided by the manufacturer.
A study done by researchers at Penn State shows that “a personal, handheld device emitting high-intensity ultraviolet light to disinfect areas by killing the novel coronavirus is now feasible”; however, “You have to ensure a sufficient UV light dose to kill all the viruses”. This means that proper UV light-emitting adequate amount of UV light dose is required to ensure that disinfection is done correctly. Otherwise, improper disinfection might be more dangerous than not disinfecting, due to the false sense of safety for the users. As most consumers do not have the lighting knowledge or equipment required to find out if a gadget is producing sufficient UV light dose, finding a practical and useful gadget is not as easy as one might think.
Screenshot 2021-06-21 200337

Issues with commonly-purchased gadgets

Common issues of the available products for household usage includes:
The price of the UV gadget can be a great pointer to see if it is a useful device or not. One single powerful UV-C LED light can cost about $15; and for a complete wand-type gadget (for surface cleaning), the device might have multiples of these (maybe even tens of LEDs). You can see that a simple device under $25 simply does not make sense to be an effective disinfectant
The issues mentioned above do not mean that there cannot be an effective handheld gadget to perform surface disinfection in households. However, they demonstrate different factors that affect the performance of such devices and how all the factors need to be considered before one decides on purchasing a gadget.


[1] Penn State. “Killing coronavirus with a handheld ultraviolet light device may be feasible.”, ScienceDaily, June 2020.

[2] G. Byrns, et al., “The uses and limitations of a hand-held germicidal ultraviolet wand for surface disinfection”, Journal of Occupational and Environmental Hygiene, June 2017.

[3] “Potential Risks Associated with The Use of Ozone and Ultraviolet (UV) Light Products for Cleaning CPAP Machines and Accessories: FDA Safety Communication”, U.S. Food and Drug Administration (FDA), Feb February 2020.

[4] J. Erdmann, “UV Light Wands Are Supposed to Kill Viruses. But Do They Really Work?”, Discover Magazine, August 2020

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