M2: Research Roundup Nanotechnology

Previous studies have demonstrated that adding multi-walled carbon nanotubes (MWCNT) can improve the performance of cement-based materials (e.g., increasing tensile strengths), even with addition of low MWCNT concentrations (e.g., 0.004% wt%). MWCNT are known to cause adverse pulmonary diseases (e.g., inflammation, cancer, mesothelioma, and fibrosis). The release of airborne particles from the manipulation of MWCNT-reinforced concrete has not been fully investigated. This study was conducted to characterize airborne particles and determine concentrations of respirable dust, silica, and elemental carbon (a surrogate for MWCNT) during dry cutting of three types of MWCNT-reinforced concrete (reference [0%], low [0.004 wt%], high [0.006 wt%]). Results indicate that all testing materials generated similar count concentration based particle size distributions with a peak at 0.72 µm and predominant respirable fractions. However, depending on the amount of MWCNT added to concrete, the respirable dust/silica concentrations could be similar or significantly different compared to the reference. No free or protruded MWCNT were observed by the methods used. This study indicates that the addition of MWCNT to concrete might need additional control measures to maintain or increase the level of protection (e.g., wet cutting) to mitigate associated with silica exposure. 

NIOSH has been at the forefront of the development and coordination of research and hazard prevention strategies for nanotechnology safety in the workplace. These institute-wide efforts have been coordinated through the NIOSH Nanotechnology Research Center (NTRC), established in 2004. As we commemorate two decades of NTRC contributions, this presentation will highlight the achievements and impact of the NTRC, as well as discuss future implications of nanotechnology and advanced materials as this technology continues to rapidly evolve and revolutionize advancements across multiple industries.