Ultraviolet light, particularly in the UVC range (280–100 nm), is known to inactivate microbes. During the current COVID-19 pandemic there’s a shortage of protective masks, particularly N95 masks that feature electrostatic filters. Cleaning such masks using liquids is not effective, as the electrostatic effect ends up neutralized, so a team at Rensselaer University created a device that bathes masks in UVC light and makes them useful again.
Inside the irradiation box are two UVC bulbs that stretch horizontally across the chamber. A motorized conveyor pulls masks, which are hung at one end of the box, in between the bulbs. The speed of the motor can be controlled to choose the desired amount of radiation exposure for the masks and to prevent over-exposure that can actually damage the structural integrity of the mask.
The design allows both sides of each mask to be illuminated, while avoiding shadows as much as possible. “Since UVC radiation is a line-of-sight disinfection process, if there’s any shadow from the mask or any material blocking the access of UVC radiation to the mask, you’re not going to disinfect that part,” said Bob Karlicek, director of the Center for Lighting Enabled Systems & Applications at Rensselaer. “We elected to come up with a system that allowed us to run the masks vertically so we could simultaneously expose the masks from both the front and the back without blocking any UVC radiation.”
The researchers are now working on testing the system at Mount Sinai hospital in New York City, using masks that have been exposed to the virus that’s causing the pandemic.
Here’s a video with the leaders of the project describing how their efforts and available equipment came together: