Metrological assessment of a portable analyzer for monitoring the particle size distribution of ultrafine particles.
Stabile-L; Cauda-E; Marini-S; Buonanno-G
Ann Occup Hyg 2014 Aug; 58(7):860-876
Adverse health effects caused by worker exposure to ultrafine particles have been detected in recent years. The scientific community focuses on the assessment of ultrafine aerosols in different microenvironments in order to determine the related worker exposure/dose levels. To this end, particle size distribution measurements have to be taken along with total particle number concentrations. The latter are obtainable through hand-held monitors. A portable particle size distribution analyzer (Nanoscan SMPS 3910, TSI Inc.) was recently commercialized, but so far no metrological assessment has been performed to characterize its performance with respect to well-established laboratory- based instruments such as the scanning mobility particle sizer (SMPS) spectrometer. The present paper compares the aerosol monitoring capability of the Nanoscan SMPS to the laboratory SMPS in order to evaluate whether the Nanoscan SMPS is suitable for field experiments designed to characterize particle exposure in different microenvironments. Tests were performed both in a Marple calm air chamber, where fresh diesel particulate matter and atomized dioctyl phthalate particles were monitored, and in microenvironments, where outdoor, urban, indoor aged, and indoor fresh aerosols were measured. Results show that the Nanoscan SMPS is able to properly measure the particle size distribution for each type of aerosol investigated, but it overestimates the total particle number concentration in the case of fresh aerosols. In particular, the test performed in the Marple chamber showed total concentrations up to twice those measured by the laboratory SMPS - likely because of the inability of the Nanoscan SMPS unipolar charger to properly charge aerosols made up of aggregated particles. Based on these findings, when field test exposure studies are conducted, the Nanoscan SMPS should be used in tandem with a condensation particle counter in order to verify and correct the particle size distribution data.
Exposure-levels; Aerosols; Aerosol-particles; Particulates; Monitors; Airborne-dusts; Airborne-particles; Respirable-dust; Nanotechnology; Analytical-processes; Analytical-instruments;
Author Keywords: diesel particulate matter; dioctyl phthalate particles; laboratory SMPS; metrological assessment; Nanoscan SMPS; occupational aerosol; particle size distribution; portable analyzer; total particle number concentration; ultrafine particles
Emanuele Cauda, National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research, 626 Cochrans Mill Road, Pittsburgh, PA 15236
Annals of Occupational Hygiene