Ultraviolet radiation is a common method of killing bacteria and viruses. Now, researchers at Tel Aviv University have proven that the new coronavirus, SARS-CoV-2, can be killed efficiently, quickly and inexpensively using ultraviolet light emitting diodes (UV) (UV-LEDs) at specific frequencies. “We found that it is very simple to kill the coronavirus using LED lamps that radiate ultraviolet light,” said Prof. Hadas Mamane, head of the Environmental Engineering Program at the Tel Aviv University School of Mechanical Engineering, who led the study with Prof. Yoram Gerchman and Dr. Michal Mandelboim. She said that ultraviolet lamps take less than half a minute to destroy more than 99.9% of coronaviruses. The study is the first of its kind in the world. An article on this was published earlier this month in Journal of Photochemistry and Photobiology B: Biology.
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UV-A has a wavelength in the range of 315 nanometers (nm) at 400 nm. UV-B, also known as medium wave light, has a wavelength of 280-315 nm; UV-C has a wavelength of 200-280 nm. UV-A is emitted by the sun (and by artificial sources such as tanning beds) and is weaker than UV-B and C. It has some human benefits, such as the creation of vitamin D, but it is also what causes burns and in some cases, skin cancer. UV-B and C radiation never reaches humans naturally because these rays are absorbed by the Earth’s ozone layer. These ultraviolet wavelengths, which are what the Tel Aviv researchers were examining, are especially effective in disinfecting using UV-LED lamps. “We know, for example, that the medical team doesn’t have time to manually disinfect, say, computer keyboards and other surfaces in hospitals – and the result is infection and quarantine,” said Mamane. “Disinfection systems based on LED lamps, however, can be installed in the ventilation and air conditioning system, for example, and sterilize the air that is sucked in and then emitted into the room.” She added that “we are also developing, together with a scientist at North Western University, a transparent coating that can be dipped or sprayed on surfaces and can kill viruses using visible light LEDs that are not dangerous and are used anywhere, providing another application for common LEDs. “In her team’s research, they were able to kill the virus using cheaper and more affordable LED lamps – 285 nm vs. 265 nm lamps – that consume little energy and do not contain mercury like normal UV lamps. She said that with the development of science, the industry will be able to produce the necessary adjustments and install the lamps in robotic systems, that is, air conditioning, vacuum and water systems, and thus be able to efficiently disinfect large surfaces and spaces. “Our research has areas and social implications, “said Mamane. She added that her team had been working on UV LEDs for a long time before the coronavirus. But when COVID-19 came along, they tried to see if they could shift their efforts to fight the human coronavirus by studying the use of LEDs to kill the corona at different frequencies. She said the 285 nm LED is 15% to 30% cheaper and requires just a little more time to be effective. ” sa that can reduce costs can help with implementation, “she said. She added that UV LEDs have an advantage because they can be turned on and off in an instant. Mamane believes that this technology is the future, adding that she hopes that by 2025, it will be profitable enough to become popular. “UV LEDs have a huge future,” he added. “Of course, as always, when it comes to ultraviolet radiation, it is important to make it clear to people that it is dangerous to try to use this method to disinfect surfaces inside the home. You need to know how to design these systems and how to work with them to not be directly exposed to light. ”