Opportunity for Companies that Produce or Handle Nanomaterials

 

We seek to collaborate with companies that

produce or handle engineered nanoparticles.

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We have funding for to develop and use novel personal sampling methods to assess airborne exposure to engineered nanoparticles through the National Institute of Occupational Safety and Health (Peters, PI; K01OH009255-01).

We have developed novel personal samplers:

(1) A real-time monitor to measure personal exposure in units of surface area concentration.

·         Ideal for attributing elevated exposures to specific work tasks and/or practices.

(2) A full-shift monitor for determining particle size distribution, chemistry, and morphology.

·         Compatible with 8-hr sampling typical of industrial hygiene monitoring.

 (3) A passive monitor for assessing chronic exposures.

·         Simple, light-weight sampler used as a dosimeter to relate exposures to chronic health effects.

 

Distinguishing Incidental from Engineered Particles.

Filter-based Sampling with Advanced Single-Particle Analysis by Electron Microscopy

Dr. Peters collaborated with Vicki Grassian’s research group to characterize airborne nanoparticle exposure hazards in a company that makes lithium titanate particles for rechargeable batteries. Filter-based sampling was used to collect samples.

Two types of particles were identified in transmission electron microscope (TEM) images (Fig. 1, left): spheres; and chain agglomerates. The spheres contained titanium, hence the lithium titanate product produced in this facility, through X-ray mapping with energy dispersive spectrometry (EDS, Fig. 1, right). Chain agglomerates contained elements characteristic of welding fume (Fig. 2).

These findings allowed us to conclude that the engineered particles were substantially larger than nanosize. Further images from scanning electron microscopy (SEM) revealed that the morphology of these particles do have nanostructure (Fig. 3). 

Fig. 1. TEM image at left; X-ray map at right. Only the large circular particles contain titanium.

Fig. 2. TEM image of chain agglomerate in the middle frame with X-ray maps around. No titanium but evidence of elements common to welding fumes (e.g. Mn) are present.

Fig. 3. SEM images show that spheres composed of fused nanoparticles ranging from 10-80 nm in size.

 

 

 

 

Activity-based Monitoring

We've used activity-based monitoring to distinguish engineered from incidental particles in manufacturing.

This monitoring involves matching real-time peaks in airborne concentrations with activities that are on-going in the facility (right).

Our results should have implications for monitoring airborne particles in work environments.