As the pandemic continues, we’re still looking for safe, effective solutions to disinfect SARS-CoV-2 from our persons, homes and businesses. Now, a team of researchers in Israel may have found a solution that’s both effective and less expensive — using light — that may make it possible to feel safer in places we’ve been avoiding for months…
We know that simply washing our hands for at least 20 seconds in soap and warm water can eradicate the virus, and that hand sanitizer is an effective alternative in situations where handwashing is not possible. And when it comes to surfaces, there are a number of disinfectant sprays and wipes that are proven effective at killing SARS-CoV-2.
But we also know that SARS-CoV-2 can be spread through respiratory droplets in the air, which is far more difficult to eradicate. Wearing masks provides some protection, but the Centers for Disease Control and Prevention still recommend keeping at least 6 feet of distance between you and another person and limiting the number of people in an enclosed space.
The CDC also recommends businesses increase outdoor ventilation and fresh air circulation where possible and season permitting, as well as installing high-efficiency particulate air (HEPA) fan or filtration systems to help enhance air cleaning.
In addition, the CDC says businesses should consider using ultraviolet germicidal irradiation (UVGI) as a supplement to help inactivate SARS-CoV-2, particularly if there are limited options for increasing room ventilation. However, existing UVGI systems can be expensive to purchase and install. Luckily, a team of researchers at Tel Aviv University have discovered a cheap and effective alternative…
Ultraviolet LEDs can kill coronavirus
In the first study conducted on the disinfection efficiency of ultraviolet light-emitting diodes (UV-LEDs) on a virus from the family of coronaviruses, the researchers have proven UV-LEDs can kill the coronavirus efficiently, quickly and cheaply. The research team used the human Coronavirus OC43 (HCoV-OC43) as a surrogate to SARS-CoV-2 in the study.
“The problem is that in order to disinfect a bus, train, sports hall or plane by chemical spraying, you need physical manpower, and in order for the spraying to be effective, you have to give the chemical time to act on the surface,” says study lead Professor Hadas Mamane of Tel Aviv University. “Disinfection systems based on LED bulbs, however, can be installed in the ventilation system and air conditioner, for example, and sterilize the air sucked in and then emitted into the room.”
Professor Mamane says that the researchers were able to kill the coronavirus using cheaper and more readily available LED bulbs, which consume little energy and do not contain mercury like regular bulbs. “Our research has commercial and societal implications, given the possibility of using such LED bulbs in all areas of our lives, safely and quickly,” she adds.
When testing the optimal wavelength for killing the coronavirus, the researchers identified a length of 285 nanometers (nm) as being almost as efficient in disinfecting the virus as a wavelength of 265 nm. The 285 nm wavelength required less than half a minute to destroy more than 99.9% of the coronaviruses. This result is good news because the cost of 285 nm LED bulbs is much lower than that of 265 nm bulbs, and the former are also more readily available.
The researchers believe that UV-LED technology will be available for private and commercial use in the near future. As the science develops, the industry will be able to make the necessary adjustments and install the bulbs in robotic systems or air conditioning, vacuum and water systems, allowing for efficient disinfection of large surfaces and spaces.
However, the researchers caution that it could be extremely dangerous to try to use the UV-LED method to disinfect surfaces inside the home. To be fully effective, the system must be designed so that a person isn’t directly exposed to the light.
Going forward, the researchers are planning to test their combination of integrated damage mechanisms and other ideas recently developed on combined efficient direct and indirect damage to bacteria and viruses on different surfaces, as well as air and water.
Keeping coronavirus at bay in your home
It’s a bummer that we can’t start using this light to kill the virus in our homes yet, but it certainly gives us hope that we may be able to soon feel safer in places like grocery stores, schools, offices and other places we’ve visited less during the pandemic.
Until then, as is the case with regularly washing your hands, routinely cleaning the surfaces in your home with soap and water is enough to significantly lower the risk of spreading COVID-19 infection. Plus, coronavirus on surfaces and objects naturally die within hours to days, with sunlight exposure reducing the amount of time the virus can survive.
However, if you want to add a level of insurance, you can scrub down your home’s surfaces using a disinfectant approved by the Environmental Protection Agency for killing SARS-CoV-2. The EPA has an interactive search tool here you can use to check if the cleaning product you want to use is on the approved list.
If you decide to mix your own disinfectant, the CDC recommends a solution of 1/3 cup of 5.25%-8.25% bleach to a gallon of water. Or you can use a 70% alcohol solution. Never mix bleach with any other cleaning or disinfection product or you could create toxic fumes.
LED lights found to kill coronavirus: Global first in fight against COVID-19 — Tel Aviv University
UV-LED disinfection of Coronavirus: Wavelength effect — Journal of Photochemistry and Photobiology B: Biology
COVID-19 (Coronavirus Disease): Ventilation in Buildings — Centers for Disease Control and Prevention
COVID-19 (Coronavirus Disease): Reopening Guidance for Cleaning and Disinfecting Public Spaces, Workplaces, Businesses, Schools, and Homes — Centers for Disease Control and Prevention