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As the COVID-19 pandemic spread across the world, researchers from ������ϲ�����’s Thomas J. Watson School of Engineering and Applied Science began work on one problem among many: How to fix the shortage of N95 medical masks.

The general practice at hospitals had been to throw away masks after each patient, but with supplies of all personal protective equipment (PPE) critically low, healthcare workers needed to use them for hours or sometimes days.

Faculty members at the Watson School’s Department of Biomedical Engineering — led by Professor and Chair Kaiming Ye — began to explore the idea of using ultraviolet light to kill the novel coronavirus. Aided by Watson staff, they built sterilization stations for ������ϲ�����-area UHS and Lourdes hospitals, and other healthcare providers have asked for the schematics to build their own stations — including the U.K.’s National Health Service.

The idea of UV sterilization is not a new one, but little or no scientific data about its potency against COVID-19 have been collected, until now. Thanks to , Ye and BME Associate Professor Guy German are beginning to test UV’s effectiveness.

“This is a fundamental study that has to be done before this technology can be put into use in a hospital,” Ye said. “People are using this technology anyway without knowing for sure that it works. This grant is to fill the knowledge gap and provide data to really make sure the sterilization delivers the expected results.”

Among the questions: Which UV wavelength works best? What is the time for UV exposure to kill COVID-19? And is the ozone produced by lower-wavelength bulbs needed for sterilization? (The gas can be “quite hazardous” if inhaled, German noted.)

“If you ask anyone at the moment, ‘Is UV irradiation a good method of disinfecting?’ — you’ll probably get a lot of yeses,” German said. “If you ask, ‘What is the dosage of UV light you need to kill the virus?’ — no one knows this yet. N95 masks have a certain thickness, and UV radiation doesn’t penetrate very far into the mask, so we don’t know if it can fully sterilize it.”

������ϲ����� labs do not have the biohazard containment facilities to experiment on COVID-19 directly, so Ye and German will inoculate the masks with Bacillus bacteria, one of the most difficult strains of microorganism to kill. If the bacteria spores do not survive UV exposure, it will show that the coronavirus can be eliminated, too.

“This is a very elegant design,” Ye said. “When we talked with the program director, he was very excited that we found a way to try to conduct the study in a much safer way that generated scientifically meaningful data for the advancement of the technology.”

The Watson professors see this research as a first step that could lead to the expansion of UV technology beyond medical settings to sterilize items at home or as part of air-filtration systems in buildings or airplanes.

“I’d like to think we came up with the most salient questions that need to be answered at this juncture,” German said.

Ye and German’s study is .