Posted on Jun 26, 2020, 6 p.m.
A team of researchers from Columbia University may have discovered a way to stop the spread of illness in crowded areas by using a particular type of ultraviolet light that kills various forms of coronavirus that is safe to use around humans.
According to the study Far-UVC light can destroy airborne droplets that are carrying the virus even with low exposure, and this unique form of UV light may be the key to safely disinfecting any spaces where people gather regularly as this light doesn’t penetrate skin or damage human cells.
“Because it’s safe to use in occupied spaces like hospitals, buses, planes, trains, train stations, schools, restaurants, offices, theaters, gyms, and anywhere that people gather indoors, far-UVC light could be used in combination with other measures, like wearing face masks and washing hands, to limit the transmission of SARS-CoV-2 and other viruses,” said Dr. David Brenner.
Both Far-UVC and regular UV rays work on the same light spectrum but Far-UVC light has a shorter wavelength and more photon energy. The study published in Scientific Reports describes how regular UV light used to kill germs has a wavelength of nanometers which is ideal for killing viruses but can be a health hazard to human skin and eyes. While Far-UVC has a wavelength ranging between 207-222 nm which was revealed to “efficiently kill pathogens potentially without harm to exposed human tissues,” as it is not able to break through the tear layer of the eye or penetrate the outer layer of dead skin cells.
Two studies tested Far-UVC against corona viruses including COVID-19 and are making the case for using this light against all types of airborne viruses. The first used a misting device to spray two common coronaviruses into the air, after exposing the contaminated air to Far-UVC lighting nearly all of the virus particles were killed: 90% in just 8 minutes, 95% after 11 minutes, 99% in 16 minutes, and after 25 minutes 99.9% of the particles were gone, even when using the regulated safe limit of lighting. The second test used the direct use of the SARS-CoV-2 strain of coronavirus that causes COVID-19, and this was demonstrated to be just as effective as the first test.
“Far-UVC light doesn’t really discriminate between coronavirus types, so we expected that it would kill SARS-CoV-2 in just the same way,” Brenner explains. “Since SARS-CoV-2 is largely spread via droplets and aerosols that are coughed and sneezed into the air it’s important to have a tool that can safely inactivate the virus while it’s in the air, particularly while people are around.”
COVID-19 spreads through droplets and aerosols that are expelled into the air by an infected person who coughs or sneezes. This study is pointing to an effective relatively cheap method of deactivating the virus while it is airborne in crowded areas. It is possible to hang overhead Far-UVC lamps/lighting at indoor public spaces and transportation without the fear of injuring any people. The researchers note that the addition of this type of lighting would be useful at lowering the spread of other viruses such as the flu as well.
"Based on our results, continuous airborne disinfection with far-UVC light at the current regulatory limit could greatly reduce the level of airborne virus in indoor environments occupied by people," says the study's lead author David Brenner, PhD, Higgins Professor of Radiation Biophysics at Columbia University Vagelos College of Physicians and Surgeons and director of the Center for Radiological Research at Columbia University Irving Medical Center.
There we have it, disinfection of public spaces can be done easily, effectively and safely at a relatively cheap price. Similar approaches are already being used in hospitals to sanitize rooms and equipment. Now it is up to the policy makers and powers that be to utilize this widely available option to add to public safety measures to help better control this outbreak that is actually backed by science.
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