Particle filtration efficiency measured using sodium chloride and polystyrene latex sphere test methods

Area of Science:

• Materials Science
• Public Health
• Engineering

Background:

• Current standards for face mask particle filtration efficiency (PFE) lack universality due to differing test methodologies.
• This ambiguity hinders direct comparison and accurate assessment of mask performance.
• Standardization is crucial for public health and informed consumer choices regarding respiratory protection.

Purpose of the Study:

• To establish an equivalence relationship between two prevalent PFE test methods.
• To provide data that can inform and improve international standards for face mask testing.
• To enable a universal understanding of PFE values across different testing protocols.

Main Methods:

• Utilized two distinct aerosol types for PFE testing: neutralized, polydisperse sodium chloride (NaCl) and unneutralized, "monodisperse" polystyrene latex sphere (PSL) aerosols.
• Conducted measurements on a large dataset comprising over 5800 real-world medical masks.
• Analyzed the collected data to determine the correlation between PFE results from the two different test methods.

Main Results:

• A quantifiable relationship was established between PFE measurements obtained using the NaCl and PSL aerosol test methods.
• The data demonstrates how results from one method can be predicted or compared to the other.
• This provides a crucial bridge for harmonizing PFE data across different regulatory frameworks.

Conclusions:

• The findings facilitate a more unified interpretation of PFE data for medical masks.
• This research supports the development of globally consistent standards for mask filtration efficiency.
• Improved standardization will enhance the reliability of mask performance assessments and public trust.