A Simple Method to Quantify Outward Leakage of Medical Face Masks and Barrier Face Coverings: Implication for the Overall Filtration Efficiency

Silvia Chiera, Alessandro Cristoforetti, Luca Benedetti, Giandomenico Nollo, Luca Borro, Lorenzo Mazzei and Francesco Tessarolo
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Silvia Chiera: Department of Industrial Engineering, University of Trento, 38123 Trento, Italy
Alessandro Cristoforetti: Department of Industrial Engineering, University of Trento, 38123 Trento, Italy
Luca Benedetti: Department of Industrial Engineering, University of Trento, 38123 Trento, Italy
Giandomenico Nollo: Department of Industrial Engineering, University of Trento, 38123 Trento, Italy
Luca Borro: 3DLab, Imaging Department, Bambino Gesù Children’s Hospital, 00165 Rome, Italy
Lorenzo Mazzei: Ergon Research, 50127 Florence, Italy
Francesco Tessarolo: Department of Industrial Engineering, University of Trento, 38123 Trento, Italy

IJERPH, 2022, vol. 19, issue 6, 1-20

Abstract: Face masking proved essential to reduce transmission of COVID-19 and other respiratory infections in indoor environments, but standards and literature do not provide simple quantitative methods for quantifying air leakage at the face seal. This study reports an original method to quantify outward leakage and how wearing style impacts on leaks and filtration efficiency. The amount of air leakage was evaluated on four medical masks and four barrier face coverings, exploiting a theoretical model and an instrumented dummy head in a range of airflows between 30 and 160 L/min. The fraction of air leaking at the face seal of the medical masks and barrier face coverings ranged from 43% to 95% of exhaled air at 30 L/min and reduced to 10–85% at 160 L/min. Filter breathability was the main driver affecting both leak fraction and total filtration efficiency that varied from 5% to 53% and from 15% to 84% at 30 and 160 L/min, respectively. Minor changes were related to wearing style, supporting indications on the correct mask use. The fraction of air leaking from medical masks and barrier face coverings during exhalation is relevant and varies according to design and wearing style. The use of highly breathable filter materials reduces air leaks and improve total filtration efficiency.

Keywords: COVID-19; SARS-CoV-2; medical face masks; surgical face masks barrier face coverings; community masks; air leak; filtration efficiency; fit testing; breathability (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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