New study! 222 nm deep UV successfully tested on humans

A joint study by Kobe University and Japanese LED component manufacturer Ushio shows that repeatedly irradiating hairless mice with skin particularly sensitive to filtered 222 nm UVC light does not cause them to develop skin cancer or cataracts. This suggests that deep UV radiation at a wavelength of 222nm is harmless to human skin and eyes.

Similarly, Columbia University in the USA also conducted relevant research. Preliminary results indicate that far-UVC at a wavelength of 222 nm cannot penetrate the skin surface or eyes, is safe for humans, and can kill viruses.

However, there has been significant controversy in the industry regarding the germicidal efficacy and safety of 222 nm UVC light. Recently, Nio and Kobe University announced the process and results of human testing.

According to reports, a research team from the Department of Plastic Surgery at Nio and Kobe University completed a study showing that irradiating human skin with filtered 222 nm UVC light reduces the number of bacteria on the skin without causing damage.

This study utilized the Care222® UV-C disinfection device from Cowtail, with a wavelength of 222 nm and radiation energy of 500 mJ/cm², including an optical filter. This short-pass filter is based on research and technology from Columbia University and has been granted a Patent; it filters out radiation with wavelengths above 230 nm.

It is reported that researchers exposed the backs of 20 healthy volunteers aged 20 to 80 years using the Care222 device. After 24 hours, none of the volunteers showed any signs of erythema on their skin.

Subsequently, to measure the bacterial count on the skin, researchers swabbed the bacteria from the volunteers' back skin and then re-exposed them to the Care222 disinfection device. The bacterial counts were divided into three stages: before exposure, 5 minutes after exposure, and 30 minutes after exposure. Final results showed that after irradiation by the Care222 disinfection device, the bacterial count decreased significantly by nearly 90%.

Notably, three months after irradiation, researchers found that no erythema signs appeared in the skin test areas of volunteers, nor were any adverse reactions observed.

Based on these test results, researchers believe that UVC with a wavelength of 222nm is safe for human skin and has bactericidal effects. Currently, this study has been published in the journal 'Public Library of Science' (PLOS ONE).

Source: LEDinside