Nanoparticles, microscopic particles with at least one dimension less than 100 nm, are a part of everyone’s daily life. You don’t have to be involved in their manufacture to be exposed to nanoparticles. Walking down the street we are exposed to vehicle exhaust (man-made nanoparticles); while on vacation at the beach everyone has come in contact with sea spray (naturally occurring nanoparticles). Smoke from a wildfire is another instance where we can be exposed to nanoparticles and we are all using products that contain engineered nanoparticles such as toothpaste, cosmetics or sunscreen. Interest in human exposure to airborne nanoparticles has grown along with the growth of nanotechnology and the potential risks associated with inhalation of nanoparticles are being evaluated by health effects experts.
The Thermophoretic Particle Sampler
Of increasing concern is exposure to engineered nanoparticles (ENP) that are specifically designed for use in the nanotechnology sector. Identifying ENP and quantifying their contributions to human exposure are important from the standpoints of source attribution and risk assessment. Effective assessment of nanoparticle exposures requires detailed characterization of the aerosol. In the article, “Development of a Transfer Function for a Personal, Thermophoretic Nanoparticle Sampler,” (David Leith, Dan Miller-Lionberg, Gary Casuccio, Traci Lersch, Hank Lentz, Anthony Marchese and John Volckens (2014), Aerosol Science and Technology), the authors describe the operation and use of a nanosampler that uses thermophoretic force to collect nanoparticles onto a standard TEM (transmission electron microscope) grid. The grid is subsequently analyzed using electron microscopy techniques to characterize and speciate the particles.
In the article, the authors describe a second-generation TPS along with the development of a transfer function that expresses the relationship between measurements (number concentration and size distribution) made using a scanning mobility particle sizer (SMPS) to the particles collected with the TPS. Based on the authors’ knowledge, this is the first thermophoretic sampling device that is fully self-contained (e.g., precipitator, battery, pump, flow control, etc.) and is sufficiently compact and light weight that it can be used in numerous applications including personal sampling.
Presently, field studies using the TPS are being conducted with government agencies (NIOSH, EPA, NASA) and industry to investigate TPS performance in real-world conditions.
For more information please contact: TPSinfo@rjleegroup.com.