
UV lamp kills coronavirus but is safe for humans
The Care222 UV lamp, which the company developed together with Columbia University, emits UV rays with a wavelength of 222 nanometers, as opposed to the conventional 254-nanometer wavelength – making them lethal to germs but benign to humans. The device, which features a specially designed bandpass filter that filters the longer UV wavelengths from the lamp, is expected to be used for disinfection at occupied spaces where people keep coming in and out and the risk of contracting the virus runs high, such as buses, trains, elevators, and offices.
At the filtered 222-nm wavelength, says the company, UV rays cannot infiltrate the surface of the skin nor the eyes to bring about cancer-causing genetic defects and other damage. At the same time, the Care222, when emitting from a ceiling, inactivates 99% of viruses and bacteria in the air and up to a three-square-meter surface of objects some 2.5 meters away from the lamp, in six to seven minutes.
In a recent research study, the Care222 UV-C disinfection module was placed 24 cm above the surface of the plates in which the viral samples were placed. The radiation intensity at the surface of the plates was 0.1 mW/cm2. The study showed that 3 mJ/cm2 of 222-nm light resulted in at least a 99.7% reduction of viable SARS-CoV-2 samples.
The researchers concluded that the study demonstrated the effectiveness of 222-nm UVC irradiation on SARS-CoV-2. The researchers further noted that the results suggest that the 222-nm UVC technology could be used for infection prevention and control against COVID-19 both in occupied and unoccupied spaces.
Unfiltered 222-nm UV-C lamps will emit radiation in the 230-nm (UV-C) to 320-nm (UV-B) range. Irradiation without blocking these higher wavelengths of light has been reported to cause erythema and damage to the cellular DNA at considerably lower levels than filtered 222-nm light.
The 1.2-kilogram Care222 UV Lamp is about the size of a hardcover book and costs 300,000 yen ($2,860). The company says it is currently only accepting orders from medical institutions but will serve other customers once production catches up with demand.
For more, see “Effectiveness of 222-nm ultraviolet light on disinfecting SARS-CoV-2 surface contamination.”
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