This paper reports the development of a novel method to measure the aerosol geometric surface area (GSA) concentration with a time resolution of a few seconds. In the method, the commercialized nanoparticle surface area monitor was used and slightly modified. The instrument responses under two different conditions were combined in a weighted sum (WS) fashion to correlate with the aerosol GSA concentration. We present the GSA concentration results and comparisons with well-known SMPS data in both laboratory testing and field measurement. For the laboratory testing, the two methods have a good agreement with a Pearson correlation coefficient of 0.9961; for the field measurements including the indoor and outdoor samplings, both methods agree well with each other. In addition, the new WS method is more stable in the clean indoor air and suitable for outdoor environmental sampling with a slight overestimation (125% of SMPS).
Bibliographical noteFunding Information:
This work was supported by 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 M Corporation, A.O. Smith 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).
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