Design, Calibration, and Field Performance of a Miniature Diffusion Size Classifier

Abstract

Due to the increasingly widespread use of engineered nanoparticles and the increasing number of persons handling them, there is a need to monitor the personal exposure of these persons. Current gravimetric and optic methods are rather insensitive for nanoparticles ( <∼ 100 nm), and therefore not suitable for this task. To help solve this problem, we have miniaturized an instrument capable of measuring nanoparticles developed earlier by our group; the diffusion size classifier (DiSC). The instrument is now handheld (4 × 9 × 18 cm), and can easily be used for personal exposure monitoring, opening up applications for workplace exposure monitoring (for engineered nanoparticles but also for traditional workplace aerosols such as welding fumes or combustion exhaust) and medical studies. The DiSC measures the particle number concentration and the average particle diameter of an aerosol, however, like most simple instruments, it is nonspecific, i.e., it detects all nanoparticles and cannot distinguish between background aerosol and specific engineered nanoparticles. In this paper, we first present the instrument design and the calibration procedure for the miniature DiSC, followed by some results from comparisons with traditional aerosol instruments in the field.

Acknowledgments

We thank Jürg Brunner and Susanne Schlatter of Umwelt- und Gesundheitsamt (UGZ) Stadt Zürich for their cooperation in the field measurements, and for sharing their CPC and SMPS data, and Christoph Hüglin (EMPA) for sharing 1 year of SMPS data of the Swiss NABEL network. We acknowledge funding by the Forschungsfonds Aargau.