UV light is highly effective at killing germs
The three main types of UV rays are UVA, UVB, and UVC. Because UVC rays have the shortest wavelength, and therefore highest energy, they are capable of killing bacteria and viruses, also called pathogens. UVC light has a wavelength of between 200 and 400 nanometers (nm). It is highly effective at decontamination because it destroys the molecular bonds that hold together the DNA of viruses and bacteria, including “superbugs,” which have developed a stronger resistance to antibiotics.
Powerful UVC light has been regularly used to decontaminate surgical tools and hospital rooms. A study that included 21,000 patients who stayed overnight in a room where someone had been previously treated found that sanitizing a hospital room with UV light in addition to traditional methods of cleaning cut transmission of drug-resistant bacteria by 30%. This is partly because UVC light can effectively sanitize hard-to-clean nooks and crannies. UVC light also works by destroying the DNA of pathogens, which makes it effective against “superbugs.”
However, it’s not quite as good as we might have hoped. In a recent study – which looked at whether UVC could be used to disinfect PPE – the authors found that, while it is possible to kill the virus this way, in one experiment it needed the highest exposure out of hundreds of viruses that have been looked at so far. The amount of ultraviolet required varied widely, depending on factors such as the shape and type of material the virus was on.
Nevertheless, a concentrated form of UVC is now on the front line in the fight against Covid-19. In China, whole buses are being lit up by the ghostly blue light each night, while squat, UVC-emitting robots have been cleaning floors in hospitals. Banks have even been using the light to disinfect their money.
How to use a UV light to kill germs at home
UV Disinfection Lamp available to consumers come in various forms, including boxes, bottles, and covered wands. Each has its own set of instructions for how to use the light to kill germs, with specifics on things like how long the sanitation takes and, in the case of wands, how close it has to be to the object you’re trying to sanitize. Larger box-shaped versions fit tablets, toys, and baby bottles.