A research team has called for a more extensive study into how sunlight is inactivating COVID-19 after realizing there is an evident difference between the newest theory and previous investigational results.
ScienceAlert reported that Paolo Luzzatto-Fegiz, a mechanical engineer at the UC Santa Barbara, together with his colleagues, noticed that the virus got inactivated as much as eight times faster in experiments compared to the most recent theoretical model predicted.
Commenting on the theory, Luzzatto-Fegiz said it assumes that inactivation works by having UVB hit the virus's RNA, impairing it.
However, he added, the discrepancy suggested something more occurring than that, and figuring it out may help manage COVID-19.
Read also: Universal Coronavirus Vaccine: Research Ongoing for Possible Solution to the Next Pandemic
UV Light
The ultraviolet part of the spectrum of UV light is easily absorbed by specific nucleic acid bases in RNA and DNA, which can cause them to attach in ways that are difficult to fix.
Nevertheless, not all UV light is the same. UVA, or longer UV waves, do not have quite adequate energy to result in problems.
It is the mid-range UVB waves in sunlight that are mainly responsible for destroying bacteria and putting the cells in danger of Sun damage.
Meanwhile, short-wave UVC radiation has been found to be effective protection from viruses like COVID-19, even while it is still enclosed in human fluids.
Nevertheless, as indicated in the study, this type of UV does not typically come into contact with the surface of the Earth and that's because of the ozone layer.
3 Times More Sensitive to UV in Sunlight
According to co-author Julie McMurry, a toxicologist at Oregon State University, "UVC is great for hospitals." However, in other environments, for example, she added, kitchens or subways, UVC would interact with the particulates to generate hazardous ozone.
In 2020, an investigational study published in The Journal of Infectious Diseases, entitled "Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces," researchers tested the impacts of UV light on COVID-19 in simulated saliva. They recorded the virus got inactivated when it was exposed to sunlight for 10 to 20 minutes.
The study investigators concluded in this paper that natural sunlight might be an effective disinfectant for contaminated nonporous objects.
In their study entitled UVB Radiation Alone May Not Explain Sunlight Inactivation of SARS-CoV-2 published in The Journal of Infectious Diseases, Luzzatto-Feigiz's team compared the results with a theory about the manner sunlight achieved this. As a result, they saw the math did not contribute to it.
Specifically, the study found that the COVID-19 virus was three times more sensitive to the UV in sunlight compared to influenza A, with 90 percent of the particles of COVID-19 being inactivated after just 50 percent of exposure to midday sunlight in summer.
'Photochemically-Damaged' RNA Molecules
Environmental calculations, which a different research team made, concluded that the RNA molecules of COVID-19 are photochemically damaged directly by light rays.
This is more strongly achieved by light's shorter wavelengths such as UVB and UVC. As UVC does not reach the surface of Earth, the study authors based their calculations of environmental light exposure on the medium-wave part of the UV spectrum.
Luzzatto and his colleagues wrote that the experimentally observed inactivation in simulated saliva is more than eight times faster than would have been expected from the theory. Therefore, the mechanical engineer said that scientists have no idea yet what's happening.
The study investigators suspect it is probable that instead of directly affecting the RNA, long-wave UVA may be interacting with molecules in the testing simulated saliva in a manner that fast-tracks the virus's inactivation.
Similar Occurrence in Wastewater Treatment
Something similar has been observed in wastewater treatment where there is a reaction from the UVA along with other substances to produce molecules that impair viruses.
If UVA can be connected to fight COVID-19, low-cost and energy-efficient wavelength-specific light sources might be helpful in enhancing air filtration systems at comparatively low risk for human health.
Referring to their finding Luzzatto-Fegiz concluded that their analysis points to the need for more experiments to test the effects of specific light wavelengths separately, as well as medium composition.
Lastly, with the virus's ability to stay suspended in the air for extended periods of time, the safest means to avoid COVID-19 in nations where it is running widespread is still wearing masks and social distancing where distancing is not possible.
A related report on how sunlight inactivates COVID-19 is shown on WION's YouTube video below:
Check out more news and information on COVID-19 on Science Times.
