Cloth Face Masks Containing Silver: Evaluating the Status.

Area of Science:

• Materials Science
• Nanotechnology
• Public Health

Background:

• Increased demand for nanosilver cloth face masks during the COVID-19 pandemic.
• Antiviral and antimicrobial claims are common, but filtration is the primary defense against virus transmission.
• Silver's known antibacterial and emerging antiviral properties drive its use in textiles.

Purpose of the Study:

• To evaluate the validity of antiviral and antimicrobial claims for 40 silver-containing cloth face masks.
• To assess if existing certifications, patents, or literature substantiate manufacturer claims.
• To identify the need for stricter federal regulations and testing standards for these products.

Main Methods:

• Analysis of 40 face masks with silver claims using publicly available methods.
• Verification of claims based on patented technology, ISO/ASTM certifications, EPA registration, and peer-reviewed literature.
• Scanning Electron Microscopy (SEM) to confirm silver presence in two selected masks.

Main Results:

• Twenty-one out of 40 masks had substantiated antiviral or antimicrobial claims.
• SEM confirmed nanosilver particles in two masks: Mask A (90-200 nm zeolite-attached silver/copper ions) and Mask B (250 nm silver/titanium particles).
• Existing certifications and patents were insufficient to guarantee claim credibility.

Conclusions:

• Current validation methods for nanosilver mask claims are inadequate.
• Stricter federal regulations and standardized testing are necessary to ensure product efficacy.
• Development of a cloth face mask inhalation standard is recommended.