Abstract
Strategies for measuring occupational exposure to aerosols composed of nanoparticles and/or ultrafine particles highlight the use of techniques for determining airborne-particle number concentration as well as number size distribution. The objective of the present work was to set up a system for conducting laboratory verification campaigns of condensation particle counters (CPCs). Providing intercomparison data as well as calibrating and checking CPCs are among the key elements in ensuring reliable laboratory or field measurement campaigns. For this purpose, the reproducible aerosol source “Calibration Tool”, initially developed by the Fraunhofer ITEM, was acquired by the Laboratory of Aerosol Metrology at INRS. As a first part of this study, a detailed characterization of the Calibration Tool developed at the laboratory is the subject of the parametric study presented here. The complete installation is named the “DCC” for “Device for Counter Check”. Used in combination with a reference counter, the DCC can now be used for routine laboratory measurements. Unlike that used for primary calibration of a CPC, the proposed protocol allows a wide range of number concentrations and particle sizes to be investigated and reproduced. The second part of this work involves comparison of the number concentrations measured by several models of CPC in parallel at the exit of a flow splitter, with respect to a reference.
Highlights
Atmospheric, indoor and workplace air naturally contains particles below 1 μm in size [1, 2]
Strategies for assessing occupational exposure to airborne nanomaterials highlight the use of timeresolved techniques to determine, among others, number concentration and size distribution
The objective of this work focused on development of a methodology to check the accuracy of Condensation Particle Counters (CPCs) prior to laboratory or field measurement campaigns
Summary
Atmospheric, indoor and workplace air naturally contains particles below 1 μm in size [1, 2]. To complete conventional sampling approaches, which provide information on the average exposure of workers, different strategies for measuring occupational exposure to airborne nanoparticles, highlighting the use of time-resolved techniques, have been developed [16,17,18,19,20] In addition to their chemical composition, airborne particles can be characterized by their number concentration as well as their size distribution. Number concentration is the most frequent characteristic used for airborne nanoparticle monitoring, task emission classification, and for evaluating the performance of protective equipment against nanoparticles Given these various issues, a methodology for checking CPCs is essential to ensure reliable laboratory or field measurement campaigns. A freshly calibrated CPC was used simultaneously as a reference measurement in compliance with standard prEN 16897 [30]
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