Throughout the COVID-19 pandemic, now entering its seventh month, a simple piece of personal protective equipment has been in short supply: N95 masks.
N95 and other medical-grade masks rely on two filtration methods: mechanical filtering by mask fibers, and electrostatic filtering, in which stationary electric charges attract and ensnare tiny 0.3-micron particles such fluid droplets containing viruses. The masks are specified for single-use only because even after a day, the electrostatic charges in the mask leak out into the air and the mask becomes less effective at filtering out particles. That gradual loss of efficiency is even worse in countries like India where high humidity speeds the loss of static charge to the air.
The problem is exacerbated when healthcare workers turn to procedures to decontaminate and reuse masks, such as baking or boiling, UV light towers, even large fumigation machines, all of which can extinguish a mask’s electrostatic charge.
“We wondered, why can’t we recharge it?” says Dov Levine, a professor of biophysics at Technion-IIT in Haifa, Israel. “Well, it turns out you can.”