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Assessment of two portable real-time particle monitors used in nanomaterial workplace exposure evaluations.

Authors
Liu-Y; Beaucham-CC; Pearce-TA; Zhuang-Z
Source
PLoS One 2014 Aug; 9(8):e105769
NIOSHTIC No.
20045121
Abstract
Background: Nanoparticle emission assessment technique was developed to semi-quantitatively evaluate nanomaterial exposures and employs a combination of filter based samples and portable real-time particle monitors, including a condensation particle counter (CPC) and an optical particle counter (OPC), to detect nanomaterial releases. This laboratory study evaluated the results from CPC and OPC simultaneously measuring a polydisperse aerosol to assess their variability and accuracy. Methods and Results: Two CPCs and two OPCs were used to evaluate a polydisperse sodium chloride aerosol within an enclosed chamber. The measurement results for number concentration versus time were compared between paired particle monitors of the same type, and to results from the Scanning Mobility Particle Spectrometer (SMPS) which was widely used to measure concentration of size-specific particles. According to analyses by using the Bland-Altman method, the CPCs displayed a constant mean percent difference of 23.8% (95% agreement limits: -9.1 to 1.6%; range of 95% agreement limit: 10.7%) with the chamber particle concentration below its dynamic upper limit (100,000 particles per cubic centimeter). The mean percent difference increased from -3.4% to -12.0% (range of 95% agreement limits: 7.1%) with increasing particle concentrations that were above the dynamic upper limit. The OPC results showed the percent difference within 15% for measurements in particles with size ranges of 300 to 500 and 500 to 1000 regardless of the particle concentration. Compared with SMPS measurements, the CPC gave a mean percent difference of 22.9% (95% agreement limits: 10.5% to 35.2%); whereas the measurements from OPC were not comparable. Conclusions: This study demonstrated that CPC and OPC are useful for measuring nanoparticle exposures but the results from an individual monitor should be interpreted based upon the instrument's technical parameters. Future research should challenge these monitors with particles of different sizes, shapes, or composition, to determine measurement comparability and accuracy across various workplace nanomaterials.
Keywords
Nanotechnology; Emission-sources; Exposure-levels; Filters; Sampling; Particulates; Monitors; Aerosols; Workers; Work-environment; Statistical-analysis; Measurement-equipment; Analytical-processes
CODEN
POLNCL
Publication Date
20140822
Document Type
Journal Article
Email Address
zaz3@cdc.gov
Fiscal Year
2014
NTIS Accession No.
NTIS Price
Identifying No.
M102014
Issue of Publication
8
ISSN
1932-6203
NIOSH Division
NPPTL; DSHEFS
Priority Area
Services
Source Name
Public Library of Science One
State
PA; OH
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