Can N95 respirators be reused after disinfection? And for how many times?

Lei Liao; Wang Xiao; Mervin Zhao; Xuanze Yu; Haotian Wang; Qiqi Wang; Steven Chu; Yi Cui

However, given that the fiber diameters are relatively small, and the filters' void space is large, the filtration efficiencies of meltblown fabrics by themselves should not be adequate for fine particle filtration (Fig. 2d) . To improve the filtration efficiency while keeping the same high air permeability, these fibers are charged through corona discharge and/or triboelectric means into quasi-permanent dipoles called electrets. 22, 23 Once they are charged, the filter can significantly increase its filtration efficiency without adding any mass or density to the structure (figure 2d). In addition, while other filter media may decrease in efficiency when loading the filter with more aerosol (NaCl, DOP), the meltblown electrets are able to keep a relatively consistent efficiency throughout the test. 24 The COVID-19 pandemic has led to a significant shortage of N95 FFRs, 25 especially amongst healthcare providers. Though the virus will eventually become inactive on the mask surface and it is unlikely to fully penetrate to the user's intake side, a recent study shows that it required 72 hours for the concentration of SARS-CoV-1 and SARS-CoV-2 viruses on plastic surfaces (40% RH and 21-23 °C) to be reduced by 3 orders of magnitude (from 10 3.7 to 10 0.6 TCID50 per milliliter of medium). 26 Assuming a similar longevity on FFR surfaces, it is . CC-BY-NC 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.