NIST: Ultraviolet light capable of cleaning N95 masks for reuse

The life of N95 masks – a component in fighting the spread of COVID-19 – may be extendable for far longer than initially thought with the use of ultraviolet light, according to recent research from the National Institute of Standards and Technology (NIST).

In a study published in the Journal of Research of the National Institute of Standards and Technology, the researchers assessed UV-exposed N95 masks for traces of virus while examining their protective and structural components to guarantee no changes occurred. They discovered that disinfection through UV light has little impact on the masks’ form or function, clearing them for reuse.

“Right now, UV technologies are really in their infancy with respect to the health care environment,” Dianne Poster, NIST research chemist/senior advisor and a co-author of the study, said. “And the data in this paper could be really instrumental in building the foundation for these applications to become more routine.”

Many healthcare facilities had begun disinfecting masks and other protective equipment for reuse during the COVID-19-induced supply shortages in 2020. However, at the time, no one was certain if methods like UV made such equipment genuinely safe and effective for reuse as N95 masks were created to be single-use. But what was a matter of no other choice, NIST scientists have shown that it was likely the right call and could make things significantly easier for future needs.

During the study, masks were each blasted with UV light 10 times, over three-minute intervals. Some of the masks were doused with a relative of SARS-CoV-2. After, researchers ran a gamut of tests, examining the masks down to their fibers, which determined no significant changes to composition, filtering ability, or breathing allowances, while eradicating most lingering viruses.

NIST partnered with two companies for this study: UV-Concepts, a manufacturer of UV-C systems not currently marketed for N95 disinfection; and ResInnova Laboratories, an antimicrobial testing company.

“UV standards developed through collaborations such as this could help us respond to the next emergency we encounter where the PPE supply chain is strained,” Poster said.