TAIPEI (Taiwan News) — The Taiwanese inventor of the modern N95 respirator has come out of retirement to help the U.S. in its battle against the Wuhan coronavirus (COVID-19).
Born in Taichung and a mechanical engineer and material scientist by trade, Dr. Peter Tsai (蔡秉燚) is the inventor of the electrostatic charging technology used in the N95 mask. An industrial version of the mask had originally been created by 3M in 1972, but in 1992, Tsai formed a team at the University of Tennessee (UT) to develop technology to enable the masks to protect against drug-resistant Tuberculosis, and he patented his virus-blocking technology in 1995.
Tsai retired from UT in 2019 and remained in Knoxville, Tenn, but as the coronavirus pandemic hit the U.S. he came out of retirement in April of 2020 to provide consulting on ways to decontaminate the N95 mask, according to NPR. As coronavirus cases continue to spiral out of control in the U.S., Tsai recently told the Washington Post that “Everyone was asking me about the respirators.”
He said that many people are asking him how to scale up the production of the respirators and how to sterilize them for reuse. Therefore, he set up a laboratory in his own home and began experimenting with ways to decontaminate the masks.
Working mainly on a volunteer basis, Tsai tried numerous methods to sterilize the masks while not degrading the filtration abilities, including washing with soap and alcohol, boiling them, steaming them, and baking them. Through trial and error, Tsai found that baking them in a hospital blanket warmer was the most effective method, according to a study he posted in the Journal of Emergency Medicine.
Tsai also found that the masks will retain 92.4 percent of their filtering efficiency (FE) after boiling, while the respirators will maintain 91.7 to 98.5 percent of FE after steaming. He did not recommend using soap and water or medical alcohol because the masks will only retain 54 percent FE with the former, while the devices will keep only 67 percent of their FE if treated with the latter.
As for homemade alternatives to the N95, he recommends nonwoven fabrics, especially car shop towels. Tsai said that the fabric is very strong and can be washed with soap and water for reuse.
Back in March, an American YouTuber created this video tutorial on how to make a mask using an inexpensive shop towel, paper clip, tape, staples, and two rubber bands. It has since gained nearly half a million views.
Tsai has also provided his expertise to N95DECON, a consortium of scientists working on ways to decontaminate N95 masks, and he has helped Tennessee-based Oak Ridge National Lab to quickly scale up production of N95 masks.
