Quantification and characterization of manufactured nanomaterials shed from face masks

Face masks are an important public health measure whose use became wide-spread during the pandemic. Manufactured nanomaterials (MNMs) have been used in face masks to enhance their anti-microbial and self-cleaning properties. There is currently a gap in the literature on the shedding potential of MNMs as it relates to potential inhalation uptake. Three face masks, containing titanium dioxide (TiO ₂ ), were analyzed for their composition and particle shedding. The face masks were first analyzed to determine the mass fraction of TiO ₂ and the composition of the particles detected. The face masks were then tested under continuous airflow with and without concurrent agitation. Particle shedding was quantified via multiple particle counters and sizers and captured on filters for additional analysis. The compositional analysis showed that all masks tested contained different levels of Ti, with TiO ₂ particles observed at the surface of the fibers. Particle shedding was observed only for two of the masks with concurrent agitation. Further analysis of the shed particles did not indicate the presence of TiO ₂ , but showed the presence of Si, Cu and Ca. This data adds to the body of evidence relating to inhalation uptake from shedding of MNMs and may inform future risk assessments.