Aerosol filtration efficiency of household materials for homemade face masks: Influence of material properties, particle size, particle electrical charge, face velocity, and leaks
Top Cited Papers
Open Access
- 8 October 2020
- journal article
- research article
- Published by Taylor & Francis Ltd in Aerosol Science and Technology
- Vol. 55 (1), 63-79
- https://doi.org/10.1080/02786826.2020.1817846
Abstract
As a consequence of the COVID-19 pandemic caused by the SARS-CoV-2 virus the widespread daily use of face masks is promoted worldwide. Particle-size dependent filtration efficiencies (FE; dp=30 nm – 10 µm), applying a particle counting approach, and additionally pressure drops (Δp) were determined for 44 samples of household materials and several medical masks. Huge FE differences were found between sample materials and for different particle sizes, spanning from 2.5 µm. Measurements at different numbers of layers showed that stacks of textiles can be treated as separate filters and total FE and Δp can readily be estimated from the features of the individual layers, leaving laborious measurements of individual combinations obsolete. For many materials, electrostatic attraction contributes strongly to overall FE for particles up to 100 nm diameter. Measurements with defined leaks showed that already a small fractional leak area of 1-2% can strongly deteriorate total FE. This is especially the case for particles smaller than 5 µm diameter, where FE dropped by 50% or even two thirds. Our measurements show that by stacking an adequate number of layers of many fabrics, decent filtration efficiencies can be reached for homemade face masks over large particle size ranges with acceptable pressure drop across the material. Very important, however, is good fit of the masks to minimize leak flows and selection of non-hazardous mask material.Keywords
This publication has 32 references indexed in Scilit:
- Characterizations of particle size distribution of the droplets exhaled by sneezeJournal of The Royal Society Interface, 2013
- Factors Affecting Filter Penetration and Quality Factor of Particulate RespiratorsAerosol and Air Quality Research, 2013
- Theoretical analysis of the motion and evaporation of exhaled respiratory droplets of mixed compositionJournal of Aerosol Science, 2011
- The role of particle size in aerosolised pathogen transmission: A reviewJournal of Infection, 2011
- Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size ParticlesAnnals of Work Exposures and Health, 2010
- Performance of an N95 Filtering Facepiece Particulate Respirator and a Surgical Mask During Human Breathing: Two Pathways for Particle PenetrationJournal of Occupational and Environmental Hygiene, 2009
- Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activitiesJournal of Aerosol Science, 2009
- Surgical mask filter and fit performanceAmerican Journal of Infection Control, 2008
- Nanotoxicology: An Emerging Discipline Evolving from Studies of Ultrafine ParticlesEnvironmental Health Perspectives, 2005
- An approximation of the bipolar charge distribution for particles in the submicron size rangeJournal of Aerosol Science, 1988