Development of a geometric surface area monitor (GSAM) for aerosol nanoparticles

Leo N.Y. Cao, Sheng Chieh Chen, Heinz Fissan, Christof Asbach, David Y Pui

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Although geometric surface area (GSA) of nanoparticles has received much attention in many fields (drug delivery, catalysts, inhalation exposure, toxicity, etc.), no appropriate instruments and methods for online measurements of GSA are readily available. Therefore, this study intends to develop a Geometric Surface Area Monitor (GSAM) to measure the GSA of spherical as well as model agglomerate/aggregate nanoparticles in nearly real-time. The GSAM consists of several existing techniques in series, including inertial impaction, unipolar charging, electrostatic precipitation, and electrical current measurement. The GSAM was first evaluated and calibrated by measuring the GSA of monodisperse nanoparticles. Spherical, aggregate, and agglomerate nanoparticles were tested in the calibration. It was found that the measured electrical current was proportional to the surface area concentration. The calibration curves obtained from the measurements of monodisperse particles was then applied for polydisperse spherical particles and compared the measured GSA with that determined by the well-known scanning mobility particle sizer (SMPS) where the GSAM had less than 10% of deviation compared with SMPS.

Original languageEnglish (US)
Pages (from-to)118-129
Number of pages12
JournalJournal of Aerosol Science
StatePublished - Dec 2017

Bibliographical note

Funding Information:
This work was supported by M Corporation, A.O. Smith Water Products Company, Applied Materials Inc., BASF Corporation, Boeing Company, China Yancheng Environmental Protection Science and Technology City, Corning Inc., Cummins Filtration Inc., Donaldson Company Inc., Entegris Inc., Ford Motor Company, Guangxi Wat Yuan Filtration System Co., Ltd., MSP Corporation, Samsung Electronics Co., Ltd, Shigematsu Works Co., Ltd, TSI Inc., W. L. Gore and Associates, Inc., Xinxiang Shengda Filtration Technology Co., Ltd, and the affiliate member of the National Institute for Occupational Safety and Health (NIOSH). National Science Foundation (NSF) Grant 1236107 , “GOALI: Unipolar Diffusion Charging of Spherical and Agglomerated Nanoparticles and its Application toward Surface-area Measurement”. The University of Minnesota thanks the support of members of the Center for Filtration Research: 3

Publisher Copyright:
© 2017 Elsevier Ltd


  • Electrostatic precipitation
  • Geometric surface area monitor
  • Real-time
  • Unipolar diffusion charging


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