Size-Dependent Filtration Efficiency of Alternative Facemask Filter Materials

Area of Science:

• Materials Science
• Public Health
• Filtration Technology

Background:

• Facemasks are crucial for mitigating the spread of airborne pathogens like coronaviruses.
• Diverse materials and designs are used in facemasks, necessitating performance evaluation.
• Understanding filtration efficiency and breathing resistance is key to selecting effective masks.

Purpose of the Study:

• To assess the size-dependent filtration efficiency and breathing resistance of various facemask materials.
• To compare the performance of household sterilization wraps, isolation media (ASTM-rated and non-ASTM-rated), and 3D-printed masks.
• To identify materials and mask designs offering optimal particle filtration.

Main Methods:

• Filtration efficiency and breathing resistance were measured using filter-holder and mannequin-in-chamber systems.
• Particle sizes ranging from 20 nm to 2 μm were analyzed.
• Performance of double-layer MERV-14 materials, ASTM-rated isolation masks, and 3D-printed masks with replaceable media was evaluated.

Main Results:

• Double-layer MERV-14 materials achieved high filtration efficiencies (94.9-73.3%) among household filter media.
• ASTM-rated isolation masks exhibited the highest filtration efficiencies overall (95.6-88.7%).
• 3D-printed mask filtration depended on sealing, influenced by media compressibility; triple-layer combinations improved efficiency.

Conclusions:

• ASTM-rated isolation masks and high-efficiency household materials offer significant particle filtration.
• Proper sealing is critical for the performance of 3D-printed masks with replaceable filters.
• Multi-layer mask designs can enhance filtration efficiency for improved protection against biological agents.