A Personal, Thermophoretic Sampler for Airborne Nanoparticles

Engineered nanoparticles possess unique properties that present potential health risks to the workers who manufacture them and to consumers who are directly or inadvertently exposed to them. Monitoring personal exposures to these materials is necessary to evaluate such potential risks. A thermal precipitator was designed to measure concentrations of airborne nanoparticles in the breathing zone of exposed individuals. Particle collection efficiency was evaluated at flow rates of 5 and 20 mL/min and for particle sizes ranging from 15 to 240 nm. Particle transmission efficiency (with the temperature gradient off) and uniformity of particle deposition across the collection surface were also evaluated. Particle collection efficiency ranged from 100% at 5 mL/min flow to approximately 50% at 20 mL/min. Particle collection was generally homogeneous near the center of the collection plate over a distance of approximately 2 mm. Particle collection was less uniform near the edges of the collection plate, with a tend...