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Far-UVC Light as a Means of Preventing the Spread of COVID-19
Far-UVC Light as a Means of Preventing the Spread of COVID-19
Written By: Paphapin Pairojtanachai
Waves of ultraviolet light, also known as germicidal UV or GUV, have been known for over a hundred years for its ability to kill infectious pathogens including viruses, bacteria, and other microorganisms. In addition, previous studies have shown that GUV can easily disarm floating microbes that transmit measles, tuberculosis, and SARS-CoV-1, which is a close relative of SARS-CoV-2, or the novel coronavirus. As it is understood that the SARS-CoV-2 can spread through aerosols, or tiny airborne particles, researchers hope to use the GUV technology as a weapon to fight against the spread of the COVID-19 as well.
Currently, UV light is being used in public transportation systems and in hospitals to sanitize surfaces, as well as to disinfect N95 masks so that healthcare workers can reuse them. Despite this, the usage of GUV has remained unincluded in the mainstream news about the COVID-19, and experts say it is due to the many misperceptions about the safety and hazards of UV light among the public, the matter of the cost of having to put the technology to use, and “a general reluctance to consider the role of aerosols in the spread of the coronavirus.”
It is widely known that the conventional ultraviolet C light or UV-C — at the wavelength of 254 nm — although effective in inactivating viruses found in airborne droplets, is dangerous to humans. However, in a recently published study conducted by researchers at Columbia University Irving Medical Center, it was found that over 99.9% of coronaviruses could be destroyed with a very low exposure of far-UVC light at a wavelength of 222 nm. According to the researchers, “continuous exposure to the far-UVC light would kill 90% of airborne viruses in about eight minutes, 95% in 11 minutes, 99% in about 16 minutes, and 99.9% in 25 minutes.”
What makes this discovery important is that at this wavelength, the far-UVC light cannot pass through the outer layer of the skin or through the eye. This means that far-UVC light could be utilized as a means of decontaminating public spaces indoors including, but not limited to, hospitals, buses, trains, train stations, restaurants, schools, theaters, cinemas, gyms, and offices, without bringing harm to skin cells. Combined with the rules of wearing face masks, washing hands, and social distancing, this technology would act as a safeguard, lowering the rate of transmission of the COVID-19.
An example of an application of this discovery is the “killing zone” that Musa Firat has installed in his restaurant, Marlaina’s Mediterranean Kitchen, in Seattle. Firat’s setup is called an “upper-room germicidal UV” since the UV system is fixed high up above the grated drop ceiling. In the dining room, there are ceiling fans that ease the flow of air and push the microscopic airborne particles through the grate, where they are blasted with electromagnetic energy from the far-UVC lights. This upper-room GUV method, along with the proper ventilation that allows for vertical air exchange, is found to be 80% effective, “equivalent to replacing the air in a room up to 24 times an hour.”
With a new understanding of this system, UV-C could possibly make a comeback in the United States and in Western Europe. Even so, it is still essential for individuals to take the airborne spread of the coronavirus seriously and wear masks, wash their hands, avoid touching their faces, and abide by social distancing rules because upper-room UV cannot block large, heavy respiratory droplets or some of the infectious aerosols in the “near field”, or those that hang around near a person’s body after coughing or sneezing.
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