Industry news

Research suggests sterilized masks remain effective

2020-03-31

BOSTON — Research conducted by the University of Massachusetts Amherst in conjunction with New England Baptist Hospital has shown that the medical face masks hospitals and health care workers rely on as they fight the coronavirus remain effective and safe for use after being sterilized.

The initial results of what UMass deemed “urgent research” indicates that “there is no real difference in filtration between a new mask and one that has been sterilized,” UMass professor and researcher Richard Peltier said, meaning the current short supply of N95 masks might be able to last longer and help ease the critical shortage of personal protective equipment for health care providers.

“While these are ordinarily disposable protective devices for medical workers, these are not ordinary times,” Peltier said. “And this science shows that sterilized face masks will protect our health care providers who are working under extraordinary conditions.”

Peltier said he was approached by New England Baptist with a question: do N95 masks continue to work effectively after they have been sterilized? Peltier worked closely with Dr. Brian Hollenbeck, chief of infectious disease at the hospital, to find an answer.

The masks were sterilized with hydrogen peroxide using a process that hospitals already use to sterilize medical instruments and were tested in Peltier’s lab.

To measure whether the sterilized masks were effective, one was placed on a mannequin head inside a chamber that was then filled with air pollution. A tube inside the mask at the mannequin’s mouth collected the air that filtered through the mask, as if the mannequin were breathing. Tools that count and estimate the size of microscopic particles were then used to analyze the air that the mannequin would have inhaled.

Peltier tested a sterilized mask and a brand-new mask right out of the box and found that there was “no difference between the two masks” in the effectiveness of filtering out harmful droplets, he said.

“In the case of a pandemic like what we have right now, there is an urgent issue to find a way around this limitation and shortage of N95 face masks,” Peltier said in a YouTube video explaining his research. “Using a sterilized face mask will protect the wearer and his or her patients from COVID-19.”

The UMass researcher said there are still some “lingering concerns” about what the sterilization process does to the foam nasal bridges, elastic straps and other aesthetic parts of the masks.

Typically, Peltier said, he would repeat his test dozens of times to collect more data but that’s not an option in this case. UMass said that New England Baptist “could not spare additional masks, which, once tested, were unusable.”

“We are no longer under ordinary circumstances and we have to improvise as best we can,” Peltier said.