“They intentionally don’t want to mention how ineffective these are,” says Shen. With only three UV-C chips powered by AA batteries, such a device would take more than a few seconds to disinfect any surface. Shen bought a handheld wand out of curiosity, which did not come with instructions. Some say to hold the light 5 centimeters above the surface for five to 10 seconds others say to hold it longer than 30 seconds.
Online instructions for the wands offer few concrete clues for disinfection times. Read more: Are Ultraviolet Sanitizing Lights Safe for Humans? Plus, most of the wands use LEDs, which are less efficient for disinfection, says Zollner. UV-C’s germicidal powers depend on the dose - how much optical energy the sourceĭelivers, the distance from the source and time of exposure, says Christian Zollner, a materials scientist at the University of California, Santa Barbara. In 2015, the Federal Trade Commission went after two companies marketing UV disinfectant devices because of false claims about eliminating foot fungus, methicillin-resistant Staphylococcus aureus, E. Smooth surfaces like marble and glass are easier to disinfect than wood or cloth. Magic Wand? Not Really, Nope!ĭuring the H1N1 influence pandemic of 2009, microbiologists warned that theĭistance and duration that a wand is held from an infected surface are both critical. The same sanitizing energy can also damage eyes and skin, and cause cancer. UV-C carries the most energy capable of destroying the bonds that hold together the DNA and RNA of viruses and bacteria, stopping them from working. Ultraviolet light has been an old friend to the disinfection world for over a century.
These three types of UV radiation differ in their biological activity and the extent to which they can penetrate the skin, says Shen. Ultraviolet light, or UV, that heads to earth courtesy of the sun and the electromagnetic spectrum, comes in three main flavors: UV-A ranges from 315 to 400 nanometers, UV-B from 280 to 315 nanometers and UV-C from 100 to 280 nanometers. “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. Since researchers have no idea of the dose, distance or time to disable SARS-CoV-2, these lights could give you a false sense of security.
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