With “hygiene” emerging as a new social watchword, LED companies are taking the opportunity to develop new ultraviolet products intended to rid settings of pathogens, even if, as we noted in an article last week, they don’t specifically go after the dreaded coronavirus. An example is Osram’s new UV-A in-car air purifier.
The 3-in.-diameter Air Zing Mini looks a bit like a small audio speaker. It is designed to clip onto ventilation covers inside a car, and to kill germs in the circulating air.
In what’s probably a case of over-excited marketing speak, Osram claims that “with ultraviolet light, the handy device can eliminate up to 99.9% of viruses and bacteria.” Even a novice observer of such things would stop and ask: Really? Exactly what viruses and bacteria are we talking about here?
It would be a surprise if Air Zing pummeled SARS-CoV-2, also known as “the novel coronavirus,” which causes COVID-19. Air Zing’s LED array emits UV-A, a long-wavelength variety of ultraviolet radiation that can be an effective germicidal agent against some bugs, but not as far as we know against the coronavirus. Studies have proven that short-wavelength ultraviolet — the UV-C band — can deactivate SARS-CoV-2. UV-C effectiveness depends on dosage, and has been proven both for conventional mercury vapor sources and for LED emitters.
But long-wavelength UV-A is another matter. If it could snuff out coronavirus, then it would seem that the Sun would be a great ally in the war against the virus, as sunlight typically delivers UV-A (as well as the mid-wavelength UV-B) to Earth. UV-C does not make it to our planet because the ozone layer blocks it.
LEDs Magazine asked Osram if the Air Zing would knock out coronavirus.
“The tests of the Air Zing Mini against the coronavirus are still ongoing,” a spokesperson replied. A titanium dioxide filter inside the product improves the overall effectiveness, she said.
So which microbes won’t survive the Air Zing and its 360‒370-nm UV-A array?
“For the bird flu virus, the removal rate was 99.95%,” the spokesperson said. While that makes for a laudable proof of concept, its usefulness is questionable given that, to our understanding, bird flu does not readily leap from human to human (if you are hauling infected chickens to market, then your car journey might be safer).
“It was also successfully tested against Staphylococcus aureus and formaldehyde,” she said. Staphylococcus aureus is the bacteria behind MRSA, also known as the “superbug,” which is resistant to some antibiotics. Formaldehyde gas has been linked to cancer.
The Air Zing can also be used as a portable device, placed in offices and the like.
Osram plans to start selling it this month in Europe for €69.99.
MARK HALPER is a contributing editor for LEDs Magazine, and an energy, technology, and business journalist ([email protected]).
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