Albert Nazeeri, a physics student at the California Institute of Technology (Caltech) in Pasadena, Calif., has found a new procedure to disinfect N95 masks.
Nazeeri said research at Caltech was shut down in response to the COVID-19 pandemic, leaving only a skeleton crew to keep an eye on things. He was tasked with keeping an eye on geologist Joseph Kirschvink’s geobiology lab during the shutdown.
“I went into the lab one or two times a week,” Nazeeri told LebTown. “I had some time, and I began thinking about the shortage of N95 masks.”
N95 masks protect the wearer from airborne particles —they’re 95 percent efficient in filtering particles and are most often used by medical personnel and first responders.
“When the novel coronavirus hit our country, N95 masks became in demand since they’re so effective. They’re also designed for one-time use, but due to the shortage, they’re being disinfected and used again,” Nazeeri explained.
To maintain the supply of N95 masks for medical workers and first responders, the Centers for Disease Control indicates that they should not be used by the general public. The CDC recommends that members of the general public use cloth face coverings. Nazeeri said N95 masks are not regulated in the United States, and there are a lot of counterfeit and fake masks being sold to unsuspecting people.
Initially, Nazeeri wanted to test the effectiveness of N95 masks.
“We have a cleaner that determines how much dust is in the air,” he said. “It’s essentially a laser particle counter. My idea was to repurpose it for testing masks.”
He tested a new N95 mask to get a base reading. Then, the mask was disinfected with a 70 percent ethanol and water solution and allowed to dry before being re-tested. Nazeeri said past wet/dry experiments done in other labs across the country have shown that filtration efficiency can decrease by nearly 40 percent after the first disinfectant treatment.
“The fibers have a surface charge, which is what enables the filtration of particles such as viruses. It’s believed that the liquids disrupt that charge on the fibers and has led to a recent CDC advisory against using alcohol for decontamination of the masks,” he explained.
Nazeeri said the drop in efficacy was replicated, but he wondered if the mask was completely dry when he tested it.
“I popped it into the vacuum drying chamber until it was completely dry,” he said. “Then it was re-tested, and I found that it was nearly as efficient as a new one.”
The measured filtering efficiency was within two percent or so of the pre-washing value, according to Nazeeri, which he has sustained for five cleaning-drying cycles so far in three models of N95 masks.
Vacuum chambers, he pointed out, are inexpensive and readily available.
“As the pandemic spreads to rural areas and developing nations, this would allow for local efforts to decontaminate, restore, monitor, and test medical masks,” Nazeeri explained.
“The process has yet to be validated using CDC/NIOSH (National Institute for Occupational Safety and Health) standard testing procedures. If validated, it may be simple enough to be set up in clinics or hospitals that have a strong enough vacuum pump,” the site reads. “We are exploring if other drying techniques that do not require a vacuum pump will also work.”
Nazeeri’s parents, Dr. Mussadiq and Sarah Nazeeri, both work at Nazeeri Family Medicine in Lebanon.
“We’re pleased to have Albert helping out during this pandemic,” Dr. Nazeeri said. “It’s important to continue to do research on vaccines and other areas that can have a positive impact. The elderly population in nursing homes is particularly vulnerable, and healthcare workers interacting with them are using N95 masks.”
He added that the Personal Protective Equipment (PPE) such as masks, gowns and gloves work well if they’re used correctly.
“It lacks the comfort most people need, but it’s important to use PPE, especially when you’re working in a healthcare setting including a skilled nursing facility,” he said.
Dr. Nazeeri advises the general public not to become complacent about social distancing and wearing masks now that stay-at-home orders have been lifted.
Albert Nazeeri said the 1918 influenza is the pandemic most frequently compared to the current crisis.
“In photos, you see people wearing cotton masks. We have more knowledge and technology, which has produced more effective masks for frontline workers, but we still need to observe social distancing and other preventive measures,” he said. “We live in a global world. Unfortunately this will not be the last pandemic. But we can learn from it. I hope the research I’ve done can be helpful.”
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