Q: Do sanitizing light wands effectively kill bacteria and other germs on surfaces?
A: Ultraviolet-C (UVC) light emitted by these hand-held devices is noted for its germicidal abilities, but it’s not clear whether using one of them prevents infections in people. The idea is that you hold the wand over an item, such as a remote control, phone, doorknob, toothbrush, or toilet seat, and presto, any germs on it disappear.
A 2014 study in the American Journal of Infection Control found that a portable wand killed 100 percent of several types of bacteria commonly found on surfaces after just five seconds, and inactivated 90 percent of especially hardy spore-forming bacteria after 40 seconds. According to the researchers, a UVC device is a reasonable alternative to using chemicals to disinfect surfaces.
But more studies are needed to see if the wands are safe, practical, and reliable. Among the safety questions are whether the devices, if not used properly, can damage skin or eyes, and whether they may produce harmful ozone during the disinfection process.
More caveats: When UVC light is shined on a surface that has nooks and crannies, it’s not likely to penetrate. Dirty, greasy surfaces also reduce the ability of UVC to penetrate. And even if the device can kill, say, 99 percent of disease-causing bacteria, that may still leave enough microorganisms to cause infection.
In 2015, in response to charges of false advertising by the Federal Trade Commission, two companies agreed to stop making claims that their UV devices disinfected everything from shoes to toilet seats. They paid hundreds of thousands of dollars in settlements.
You don’t need a UV device (which costs about $60 to $80) to kill microbes. Simply washing surfaces, as well as your hands, with soap and water is effective, if done well. You can also use cheaper disinfectant wipes or a paper towel moistened with a hand sanitizer that contains at least 60 percent alcohol. Note also that these sanitizing wands are different from portable UV water purifiers, which are effective and serve a purpose if you need to disinfect your drinking water, such as when hiking or traveling.
Also see 6 Things About Hand Sanitizers.