Published June 15, 2021 by Bowdoin Magazine

UV Light

When the pandemic hit in March 2020, Professor of Physics Dale Syphers was in the middle of his sabbatical, researching forensic physics. He “turned on a dime” and threw himself into the study of how ultraviolet (UV) light can be deployed in the fight against COVID-19 and other viruses.

Exposing personal protective equipment, like N-95 respirators, to shortwave ultraviolet light clears them of active viruses, allowing health care workers to safely reuse the gear. But over time, repeated exposure to UV light can degrade the mask materials, making them ineffective.

With research assistant Joyce Bor ’22, Syphers has been investigating the shortest amount of time respirators need to be exposed to UV light, and at what level, to render viral loads inactive. While 99 percent of the viral load on a mask is killed within the first few seconds of UV exposure, the remaining 1 percent takes twenty times longer to become deactivated. As UV beams penetrate a mask, photons bounce off the fibers of the filter layers. Some of the UV light bounces backward before doubling back and piercing the mask, slowing the deactivation process. In collaboration with a virologist at the University of New England, Bor and Syphers conduct their UV exposure experiments in a box constructed specifically to deactivate viruses on N-95 masks. The intention is to send these boxes, with assistance from international relief agencies, to clinics around the world.

“In the long run, we believe the UV box under development could be especially useful in areas of the world with limited means, allowing N-95 respirators to be reused safely up to twenty-five times, and probably useful here in the US for everything from EMTs to doctors’ offices and hospitals,” Syphers said.

Additionally, the findings Syphers and Bor have made into how UV light bounces off mask fibers could lead to better-designed masks that can be reused even more often—perhaps hundreds of times.

For more of this story, read the full piece as it originally appeared in Bowdoin News. 

Bowdoin Magazine, Spring/Summer 2021


This story first appeared in the Spring/Summer 2021 issue of Bowdoin Magazine. Manage your subscription and see other stories from the magazine on the Bowdoin Magazine website.