November 17, 2020 Volume 16 Issue 44

Designfax weekly eMagazine

Subscribe Today!
image of Designfax newsletter


View Archives


Manufacturing Center
Product Spotlight

Modern Applications News
Metalworking Ideas For
Today's Job Shops

Tooling and Production
Strategies for large
metalworking plants

Study is first to show proof that safer UV light kills COVID-19 virus

Hiroshima University researchers found that using Ultraviolet C light with a 222-nm wavelength, which doesn't harm living cells in the human eye and skin, effectively kills the SARS-CoV-2 virus. [Photo credit: Hiroshima University]





A study conducted by Hiroshima University researchers in Japan found that using Ultraviolet C light with a wavelength of 222 nanometers (nm), which is safer to use around humans, effectively kills SARS-CoV-2. It is the first research in the world to prove its efficacy against the virus that causes COVID-19.

Other studies involving 222-nm UVC, also known as Far-UVC, have so far only looked at its potency in eradicating seasonal coronaviruses that are structurally similar to the SARS-CoV-2, but not on the COVID-19-causing virus itself. A nanometer is equivalent to one-billionth of a meter.

An in-vitro experiment by HU researchers showed that 99.7% of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222-nm UVC irradiation at 0.1 mW/cm2. The study is published in the American Journal of Infection Control.

Tests were conducted using Ushio's Care222 krypton-chloride excimer lamp, which is commercially available. A 100-microliter solution containing the virus (ca. 5 × 106 TCID50/mL) was spread onto a 9-cm sterile polystyrene plate. The researchers allowed it to dry in a biosafety cabinet at room temperature before placing the Far-UVC lamp 24 cm above the surface of the plates.

A wavelength of 222-nm UVC cannot penetrate the outer, non-living layer of the human eye and skin, so it won't cause harm to the living cells beneath. This makes it a safer, but equally potent, alternative to the more damaging 254-nm UVC germicidal lamps increasingly used in disinfecting healthcare facilities.

Since 254-nm UVC can harm exposed human tissues, it can only be used to sanitize empty rooms. The 222-nm UVC lights, however, may prove to be a promising disinfection system for occupied public spaces including hospitals, where nosocomial (originating in the hospital) infections are a possibility.

The researchers are stressing further evaluation of the safety and effectiveness of 222-nm UVC irradiation in killing SARS-CoV-2 viruses in real-world surfaces, as their study only investigated its in-vitro efficacy.

This Far-UVC research was one of four COVID-19 studies conducted by Hiroshima University scientists that received funding from the Japan Agency for Medical Research and Development.

Designfax Editor's Note: These study results need more investigation -- especially because they could affect important health issues. We do not encourage buying 222-nm UVC bulbs at this time based solely on these findings. Overall, this looks like a promising development.

Source: Hiroshima University

Published November 2020

Rate this article

[Study is first to show proof that safer UV light kills COVID-19 virus]

Very interesting, with information I can use
Interesting, with information I may use
Interesting, but not applicable to my operation
Not interesting or inaccurate

E-mail Address (required):


Type the number:

Copyright © 2020 by Nelson Publishing, Inc. All rights reserved. Reproduction Prohibited.
View our terms of use and privacy policy