JAMA Intern Med: A study of filtration efficiency of alternatives to N95 masks.

N95 masks are an important medical material to prevent the spread of new coronary pneumonia, and in the face of severe outbreaks, many non-standard methods have to be used, such as using expired masks or secondary disinfection of masks to extend the life of masks.
recently examined the filtration efficiency (FFEs) of alternatives using N95 masks during the COVID-19 pandemic.
researchers evaluated FFFEs for various masks between April and June 2020, based on the Occupational Safety and Health Administration's suitability testing program.
end of the study was the filtration efficiency of the N95 mask substitute.
the researchers evaluated 29 different types of mask alternatives and found that the expired N95 masks with intact elastic bands and the N95 masks, which were sterilized with ethylene oxide and hydrogen peroxide, showed no change in FFFE.
performance of N95 masks of inappropriate size (90%-95% FFE value) was slightly reduced, while other methods failed to achieve 95% FFE.
two imported masks authorized by the U.S. Centers for Disease Control and Prevention for use that were not confirmed by NIOSH did not reach 95 percent FFFE in this study, with a filtering efficiency of about 80 percent.
surgical masks and masks have lower filtration performance than N95 masks, with the least efficient masks with elastic earrings fixed (FFE 38.1%).
research believes that during the COVID-19 pandemic, in the face of the shortage of N95 masks, the use of expired complete N95 masks or secondary disinfection of N95 masks can extend the service life, while the filtration effect of other alternatives is difficult to meet the requirements of high-risk medical environments.
.