Special Issue on COVID-19 Aerosol Drivers, Impacts and Mitigation

Karin Ardon-Dryer This email address is being protected from spambots. You need JavaScript enabled to view it.1, Juliusz Warzywoda This email address is being protected from spambots. You need JavaScript enabled to view it.2, Rumeysa Tekin2, Jnev Biros3, Sharilyn Almodovar4, Brandon L. Weeks5, Louisa J. Hope-Weeks6, Albert Sacco Jr.3 

1 Department of Geosciences, Atmospheric Science Group, Texas Tech University, Lubbock, TX 79409, USA
2 Materials Characterization Center, Edward E. Whitacre Jr. College of Engineering, Texas Tech University, Lubbock, TX 79409, USA
3 Edward E. Whitacre Jr. College of Engineering, Texas Tech University, Lubbock, TX 79409, USA
4 Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
5 Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA
6 Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA

Received: September 25, 2020
Revised: January 24, 2021
Accepted: March 12, 2021

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.200571  

Cite this article:

Ardon-Dryer, K., Warzywoda, J., Tekin, R., Biros, J., Almodovar, S., Weeks, B.L., Hope-Weeks, L.J., Sacco, A. Jr. (2021). Mask Material Filtration Efficiency and Mask Fitting at the Crossroads: Implications during Pandemic Times. Aerosol Air Qual. Res. https://doi.org/10.4209/aaqr.200571 


  • Filtration performance of masks dramatically decreases without proper fitting.
  • Mask design and filtration efficiency equally contribute to mask performance.
  • Structure and chemical composition of mask materials can define filtration efficiency.


The COVID-19 pandemic triggered the widespread use and need for respirators and face masks for the healthcare workers and public. In this study, several generally available respirators and mask designs were fit tested, and their materials were evaluated for filtration efficiency using 250 nm polystyrene latex particles. Efficiency testing was performed for 2 and 0.5 h at low (2.6 L min-1) and high (7.4 L min-1) airflows, respectively, using ~17.4 cm2 material area. As expected, all N95 and KN95 respirators passed the fit test, and their materials showed efficiencies >95% for the entire experiment at both airflows. Of the three air filters used in the 3D-printed Montana masks, only the HEPA filter had a filtration efficiency >95% at both airflows. Regardless of the insert material, the Montana mask failed all fit tests. Homemade duckbill masks made of Halyard H600 sterilization wrap and WypAll X80 reusable wipe also failed the fit test, and both filter materials had an average filtration efficiency <95% at high airflows. To explain the filtration efficiency results, the structure and composition of all filter materials were determined using FE-SEM, and IR and Raman spectroscopy. In conclusion, when highly efficient materials are used in masks that do not fit the users properly, the potential of these materials to protect the users from aerosols is compromised. Therefore, the mask design is as important as the filtration efficiency of the mask material.

Keywords: Respirators, Face masks, Duckbill masks, Filtration efficiency

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