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Last-resort strategies during mask shortages: optimal design features of cloth masks and decontamination of disposable masks during the COVID-19 pandemic
  1. Shovon Bhattacharjee1,2,
  2. Prateek Bahl3,
  3. Abrar Ahmad Chughtai4 and
  4. C Raina MacIntyre1,5
  1. 1Biosecurity Program, Kirby Institute, UNSW Sydney, Kensington, New South Wales, Australia
  2. 2Department of Applied Chemistry and Chemical Engineering, Noakhali Science and Technology University, Noakhali, Bangladesh
  3. 3School of Mechanical and Manufacturing Engineering, UNSW Sydney, Kensington, New South Wales, Australia
  4. 4School of Public Health and Community Medicine, UNSW Sydney, Kensington, New South Wales, Australia
  5. 5College of Public Service and Community Solutions and College of Health Solutions, Arizona State University, Tempe, Arizona, USA
  1. Correspondence to Shovon Bhattacharjee; shovon.bhattacharjee{at}


Face masks and respirators are the most widely used intervention measures for respiratory protection. In the wake of COVID-19, in response to shortages and lack of availability of surgical masks and respirators, the use of cloth masks has become a research focus. Various fabrics have been promoted with little evidence-based foundation and without guidelines on design principles for optimal performance. In these circumstances, it is essential to understand the properties, key performance factors, filter mechanisms and evidence on cloth masks materials. The general community might also need to decontaminate and reuse disposable, single-use devices as a last resort. We present an overview of the filter materials, filter mechanisms and effectiveness, key performance factors, and hydrophobicity of the common disposable masks, as well as cloth masks. We also reviewed decontamination methods for disposable respiratory devices. As an alternative to surgical masks and respirators, we recommend a cloth mask made of at least three layers (300–350 threads per inch) and adding a nylon stocking layer over the mask for a better fit. Water-resistant fabrics (polyesters/nylon), blends of fabrics and water-absorbing fabrics (cotton) should be in the outside layer, middle layer/layers and inside layer, respectively. The information outlined here will help people to navigate their choices if facing shortages of appropriate respiratory protection during the COVID-19 pandemic.

  • infection control
  • equipment evaluations

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  • Contributors The manuscript was written through the contributions of all the authors. SB conceptualised and designed the study, analysed the data, and drafted the manuscript. PB analysed the data and revised the manuscript. AAC supervised the study and revised the manuscript. CRM conceptualised the study, supervised the study and revised the manuscript.

  • Funding This work was supported by a grant from the NHMRC Centre for Research Excellence, Integrated Systems for Epidemic Response (ISER) (grant number 1107393). CRM is supported by an NHMRC Principal Research Fellowship (grant number 1137582). SB is supported by a UNSW Scientia PhD scholarship.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.