A study developed by several researchers from different universities (UC Santa Barbara, Oregon State University, University of Manchester and ETH Zurich) provides the first evidence that sunlight can rapidly inactivate the coronavirus on surfaces, suggesting that persistence, and subsequently the risk of exposure, can vary significantly between indoor and outdoor environments.
The report, published in The Journal of Infectious Diseases, notes that laboratory experiments show inactivation of sunlight more than eight times faster than previously thought based on previous research.
“The theory had predicted that inactivation should occur an order of magnitude slower. In experiments, viruses in simulated saliva and exposed to UV-B lamps went inactive more than eight times faster than the theory would have predicted, “said UC Santa Barbara professor of mechanical engineering and lead author Paolo Luzzatto-Fegiz.
These data would indicate that natural sunlight can be effective as a disinfectant for materials not dangerous contaminated with the virus.
In July 2020, an experimental study had already tested the effects of UV light on the coronavirus in simulated saliva. They recorded that the virus was inactivated when exposed to simulated sunlight for between 10 and 20 minutes. Now, sunlight is known to act much faster.