Performance Comparison of Real-Time Light Scattering Dust Monitors Across Dust Types and Humidity Levels

  • Justin R. PattsEmail author
  • Donald P. Tuchman
  • Elaine N. Rubinstein
  • Emanuele G. Cauda
  • Andrew B. Cecala


Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust.


Light scattering instrument Industrial mineral dusts Respirable dust sampler Aerosol sampling methods Equivalency factor 



We are grateful to NIOSH researcher James Noll who helped to design and pilot studies in this area. We also appreciate the experience and expertise of NIOSH technicians Joe Archer and Jeanne Zimmer (both retired) for their execution of the tests in the Marple chamber and handling of the gravimetric filters. Finally, we thank Jarod Myers for conducting the bulk particle sizing.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.


The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not constitute an endorsement by NIOSH.


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© This is a U.S. government work and its text is not subject to copyright protection in the United States; however, its text may be subject to foreign copyright protection  2019

Authors and Affiliations

  1. 1.National Institute for Occupational Safety and HealthPittsburgh Mining Research DivisionPittsburghUSA

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