N95 respirator masks are meant to be disposable, but a worldwide shortage of personal protective equipment (PPE) has forced people to sanitize and reuse the mask. Researchers from the University of Illinois found that an electric cooker can effectively decontaminate N95 masks.
An electric cooker like an instant pot or a rice cooker can be used to safely sanitize N95 respirators with about 50 minutes of dry heat. The paper from the University of Illinois has been published in the journal Environmental Science and Technology Letters.
Thanh "Helen" Nguyen described how effective N95 respirators are against the droplets and other particles that may be carrying coronavirus. The lack of PPE during the pandemic has forced medical staff to sanitize their masks for reuse.
Although the best way to sanitize PPE is through ultraviolet light, not everyone has access to such technology. Instead, people have been looking for alternative ways to disinfect their N95 respirators and other PPE safely.
Effective Decontamination
Although there are several ways to sterilize the N95 mask, not all sanitation methods can effectively decontaminate the mask without causing damage to some parts, explained Vishal Verma. "Maintaining the filtration efficacy and the fit of the respirator to the face of the wearer is essential," said Verma.
The team focused on how dry heat would meet the criteria of decontamination, fit, and filtration. They wanted to find a way to easily decontaminate an N95 respirator that would not require extensive preparation, including chemicals, and be easily done by anyone within their homes.
A separate team from the National Institute of Allergy and Infectious Diseases in Hamilton, Montana, also conducted several decontamination experiments as well. "Our results indicate that N95 respirators can be decontaminated and reused in times of shortage for up to three times for UV and HPV, and up to two times for dry heat."
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Using an Electric Cooker
Testing an electric cooker seemed like the best choice. One cooking cycle that lasted for 50 minutes at 212 degrees Fahrenheit effectively decontaminated N95 masks from four types of viruses, including coronavirus. This cleaning method was more effective than ultraviolet light, said the team.
"We built a chamber in my aerosol-testing lab specifically to look at the filtration of the N95 respirators, and measured particles going through it," Verma said. "The respirators maintained their filtration capacity of more than 95 percent and kept their fit, still properly seated on the wearer's face, even after 20 cycles of decontamination in the electric cooker."
In their video demonstration, they noted that it was important for no water to be added for the cooker to maintain maximum heat. They also covered the bottom of the Farberware cooker with a towel, so its heating element would not damage the N95 respirator. Multiple masks could be stacked inside too as long as they don't come in direct contact with the bottom and sides of the cooker.
Their research is especially useful for clinics and hospitals without large-scale heat sanitization equipment, health care workers, and first responders.
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