Leo N.Y. Cao 1, David Y.H. Pui2

1 Division of Complex Drug Analysis, US Food and Drug Administration, St. Louis, MO 63110, USA
2 Particle Technology Laboratory, University of Minnesota, Minneapolis, MN 55455, USA

Received: December 6, 2019
Revised: December 6, 2019
Accepted: February 3, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.2019.12.0621 

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Cite this article:

Cao, L.N. and Pui, D.Y. (2020). Real-time Measurements of Particle Geometric Surface Area by the Weighted Sum Method on a University Campus. Aerosol Air Qual. Res., https://doi.org/10.4209/aaqr.2019.12.0621


  • Various online measurements of particle GSA on a university campus were conducted.
  • Events included laser printing, 3D printing, machining, and the ambient environment.
  • Overall Pearson correlation coefficient is 0.85 for the agreement of WS and SMPS.
  • The study offered a GSA concentration reference for future studies.


This study conducted field measurements of the particle geometric surface area (GSA) and number concentrations on a university campus via two real-time approaches: applying the weighted-sum (WS) method and using a Scanning Mobility Particle Sizer (SMPS). The measurements were conducted on 4 subjects: laser printing, 3D printing, machining (waterjet cutting, sanding, and welding), and environmental aerosols. The highest emissions were found with 3D printing and welding; these concentrations were measured in the printer’s enclosure and when the local exhaust ventilation was on, respectively. In general, the two methods agreed well with each other, with an overall Pearson correlation coefficient of 0.85, although the concentrations constantly fluctuated over a wide range, from 20 to 4 × 104 μm2 cm–3. Since the GSA concentrations reported in this study are the first measurements for some scenarios, our results can serve as a reference for further research as well as for individuals in the vicinity of these emissions.

Keywords: Geometric surface area; Real-time; Weighted sum; Occupational exposure; 3D printing emission.

Aerosol Air Qual. Res. 20:-. https://doi.org/10.4209/aaqr.2019.12.0621 

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5-Year Impact Factor: 2.827

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