Researchers from Henry Ford Health System and the University of Michigan found that ultraviolet-C light (UV-C) can kill COVID-19 on certain N95 respirators.
The researchers found the outside and inside of the facemasks were decontaminated in a prototype phototherapy unit that disperses UV-C at a level high enough to kill the virus in less than two minutes while preserving the facemasks' breathability, fit and integrity.
Five different N95 models were tested, and the decontamination process worked best on two models – facepieces on 3M 1860 and Moldex 1511 and straps on the 3M 8210 and Moldex 1511.
The effects varied on other models and their straps, which suggests the UV-C radiation can degrade them.
“Our findings reveal a practical, and viable option should hospitals encounter shortages of N95s in the future,” the study's lead author, Dr. David Ozog, chair of Henry Ford’s Department of Dermatology, said in a release. “Using UV-C has been shown to be effective in killing other coronaviruses and the flu virus. We were able to replicate that sterilization effectiveness with COVID-19.”
The testing was done at U-M's SARS-CoV-2 research lab in Ann Arbor.
The team consisted of dermatologists and researchers and they spent more than 400 hours since the COVID-19 pandemic began testing how phototherapy could help keep masks safe for re-use.