Abstract
ABSTRACT The emergence of the recent COVID-19 pandemic has rendered mandatory wearing of respiratory masks by infected persons, frontline workers, security personnel and members of the public. This has caused a sudden shift of focus, and significant demand on availability, effectiveness, reuse after sterilisation and development of facemask. Toward this, three types of masks viz. N95, non-woven fabric and double layer cotton cloth are being used by the majority of the population across the world as an essential inhalation protective measure for suppressing the entry of virus-laden respiratory droplets. The Filtering Efficiency (FE) of these masks are tested for atmospheric and laboratory-generated aerosols of size 1.0 µm and 102.7 nm particles before and after sterilisation and the two flow rate conditions corresponding to normal breath rate and during sneezing/coughing. Sterilisation is carried out using a gamma irradiator containing Co-60 source for the two-dose exposures viz. 15 kGy and 25 kGy. The FE of surgical and cloth masks is found to be in the range of 15.76 ± 0.22 to 22.48 ± 3.92%, 49.20 ± 8.44 to 60 ± 7.59% and 73.15 ± 3.73 to 90.36 ± 4.69% for aerosol sizes 0.3–5.0, 1.0–5.0 and 3.0–5.0 µm atmospheric aerosols respectively. The FE of cloth and surgical masks ranges from 45.07 ± 6.69% to 63.89 ± 4.44% and 56.58 ± 1.69% to 83.95 ± 1.04% for 1.0 µm laboratory-generated aerosol for two flow rate, control and irradiated conditions. The FE of N95 mask is found to be more than 95% for atmospheric aerosol, and 1.0 µm laboratory-generated aerosol. However, FE reduced to about 70% for most penetrating particle size after sterilisation. Further, FE reduced to 84% for the particle > 0.3 µm and to 87% for the particle < 0.3 µm after sterilisation. The reduction in FE for N95 mask after sterilization is associated with the reduction of electrostatic interaction of filter medium with particles laden in the air stream. Instead of disposing of N95 masks after a single use, they can be reused a few times as N70 mask during this pandemic crisis after sterilisation. The use of cotton cloth masks in the general public serves fit for the purpose than surgical masks.
Highlights
The masks being tested is fixed into an air duct, and ambient particulates are flown through the facemask with a face velocity of 0.058 ± 0.002 and 0.264 ± 0.009 m s–1 corresponding to 20 ± 0.2 and 90 ± 1.0 L min–1 flow rates respectively
The Filtering Efficiency (FE) of surgical masks is more than cloth masks for 102.7 nm aerosols for 20 L min–1 while in case of 90 L min–1 flow rate, the FE of cloth masks is more compared to the surgical masks
Three types of facemask viz. N95, surgical mask and self-made double layer cloth mask have been tested for particulate filtering efficiency for two-flow rate condition viz. 20 and 90 L min–1 before and after gamma sterilization using atmospheric aerosols in size range of 0.3–5 μm and laboratory-generated aerosols of size 1.0 μm and 102.7 nm (PSL)
Summary
Copyright: The Author(s).This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.The corona virus disease (COVID-19) is a new type of disease that started spreading from December 2019 and presently, affected more than 200 countries across the territories around the globe. As of now (26 June 2020), more than 9 million positive cases and more than 0.4 million deaths indicate the severity of the current pandemic (Worldometer, 2020; https://www.worldometers.i nfo/coronavirus/). In general, the spread of the corona virus infection can occur through contact (direct and/or indirect), droplet spray in short-range (for droplet diameter greater than 5 μm) and long range by airborne transmission of aerosols (aerosol diameter less than 5 μm) when an infected person coughs, sneezes and talks. Further, the transport of droplet and aerosols depends
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
