Shubham Sharma1, Roven Pinto1, Abhishek Saha2, Swetaprovo Chaudhuri3, Saptarshi Basu4. 1. Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, KA 560012, India. 2. Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA. 3. Institute for Aerospace Studies, University of Toronto, Toronto, ON M3H 5T6, Canada. 4. Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, KA 560012, India. sbasu@iisc.ac.in.
Abstract
Face masks prevent transmission of infectious respiratory diseases by blocking large droplets and aerosols during exhalation or inhalation. While three-layer masks are generally advised, many commonly available or makeshift masks contain single or double layers. Using carefully designed experiments involving high-speed imaging along with physics-based analysis, we show that high-momentum, large-sized (>250 micrometer) surrogate cough droplets can penetrate single- or double-layer mask material to a significant extent. The penetrated droplets can atomize into numerous much smaller (<100 micrometer) droplets, which could remain airborne for a significant time. The possibility of secondary atomization of high-momentum cough droplets by hydrodynamic focusing and extrusion through the microscale pores in the fibrous network of the single/double-layer mask material needs to be considered in determining mask efficacy. Three-layer masks can effectively block these droplets and thus could be ubiquitously used as a key tool against COVID-19 or similar respiratory diseases.
Face masks prevent transmission of infectious respiratory diseases by blocking large droplets and aerosols during exhalation or inhalation. While three-layer masks are generally advised, many commonly available or makeshift masks contain single or double layers. Using carefully designed experiments involving high-speed imaging along with physics-based analysis, we show that high-momentum, large-sized (>250 micrometer) surrogate cough droplets can penetrate single- or double-layer mask material to a significant extent. The penetrated droplets can atomize into numerous much smaller (<100 micrometer) droplets, which could remain airborne for a significant time. The possibility of secondary atomization of high-momentum cough droplets by hydrodynamic focusing and extrusion through the microscale pores in the fibrous network of the single/double-layer mask material needs to be considered in determining mask efficacy. Three-layer masks can effectively block these droplets and thus could be ubiquitously used as a key tool against COVID-19 or similar respiratory diseases.
Authors: Stefan Kniesburges; Patrick Schlegel; Gregor Peters; Caroline Westphalen; Bernhard Jakubaß; Reinhard Veltrup; Andreas M Kist; Michael Döllinger; Sophia Gantner; Liudmila Kuranova; Tobias Benthaus; Marion Semmler; Matthias Echternach Journal: J Expo Sci Environ Epidemiol Date: 2021-10-05 Impact factor: 6.371
Authors: Kai Man Alexander Ho; Hywel Davies; Ruth Epstein; Paul Bassett; Áine Hogan; Yusuf Kabir; John Rubin; Gee Yen Shin; Jonathan P Reid; Ryo Torii; Manish K Tiwari; Ramanarayanan Balachandran; Laurence B Lovat Journal: Sci Rep Date: 2021-12-17 Impact factor: 4.379