Objective We examined the ability of fabrics which might be used to create home-made face masks to filter out ultrafine (0.02–0.1 µm) particles at the velocity of adult human coughing.
Methods Twenty commonly available fabrics and materials were evaluated for their ability to reduce air concentrations of ultrafine particles at coughing face velocities. Further assessment was made on the filtration ability of selected fabrics while damp and of fabric combinations which might be used to construct home-made masks.
Results Single fabric layers blocked a range of ultrafine particles. When fabrics were layered, a higher percentage of ultrafine particles were filtered. The average filtration efficiency of single layer fabrics and of layered combination was found to be 35% and 45%, respectively. Non-woven fusible interfacing, when combined with other fabrics, could add up to 11% additional filtration efficiency. However, fabric and fabric combinations were more difficult to breathe through than N95 masks.
Conclusions The current coronavirus pandemic has left many communities without access to N95 face masks. Our findings suggest that face masks made from layered common fabric can help filter ultrafine particles and provide some protection for the wearer when commercial face masks are unavailable.
- public health
- infection control
- respiratory infections
- infectious diseases
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Contributors EOK conceived of the study, developed the study methodology, obtained the study materials and testing apparatus, collected study data, and wrote the manuscript. SP obtained the study materials, analysed the data and performed calculations, designed the graphs, and edited the manuscript. JW and JC developed the study methodology, reviewed the data, edited the manuscript and supervised the study.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available in a public, open access repository. Data from this study are freely available under a CC BY licence on Cambridge University’s Apollo data repository, citation:
O’Kelly, E. The ability of common fabrics to filter ultrafine particles (data file), Cambridge University: Cambridge, UK, 2020; https://doi.org/10.17863/CAM.51390.
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