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Efficacy of a portable, moderate-resolution, fast-scanning differential mobility analyzer for ambient aerosol size distribution measurements

Amanatidis​​​​​​​, Stavros and Huang, Yuanlong and Pushpawela, Buddhi and Schulze, Benjamin C. and Kenseth, Christopher M. and Ward, Ryan X. and Seinfeld, John H. and Hering, Susanne V. and Flagan, Richard C. (2021) Efficacy of a portable, moderate-resolution, fast-scanning differential mobility analyzer for ambient aerosol size distribution measurements. Atmospheric Measurement Techniques, 14 (6). pp. 4507-4516. ISSN 1867-8548. doi:10.5194/amt-14-4507-2021.

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Ambient aerosol size distributions obtained with a compact scanning mobility analyzer, the “Spider” differential mobility analyzer (DMA), are compared to those obtained with a conventional mobility analyzer, with specific attention to the effect of mobility resolution on the measured size distribution parameters. The Spider is a 12 cm diameter radial differential mobility analyzer that spans the 10–500 nm size range with 30 s mobility scans. It achieves its compact size by operating at a nominal mobility resolution R=3 (sheath flow = 0.9 L min⁻¹; aerosol flow = 0.3 L min⁻¹) in place of the higher ratio of sheath flow to aerosol flow commonly used. The question addressed here is whether the lower resolution is sufficient to capture key characteristics of ambient aerosol size distributions. The Spider, operated at R=3 with 30 s up- and downscans, was co-located with a TSI 3081 long-column mobility analyzer, operated at R=10 with a 360 s sampling duty cycle. Ambient aerosol data were collected over 26 consecutive days of continuous operation, in Pasadena, CA. Over the 17–500 nm size range, the two instruments exhibit excellent correlation in the total particle number concentrations and geometric mean diameters, with regression slopes of 1.13 and 1.00, respectively. Our results suggest that particle sizing at a lower resolution than typically employed may be sufficient to obtain key properties of ambient size distributions, at least for these two moments of the size distribution. Moreover, it enables better counting statistics, as the wider transfer function for a given aerosol flow rate results in a higher counting rate.

Item Type:Article
Related URLs:
URLURL TypeDescription supplement
Amanatidis​​​​​​​, Stavros0000-0002-4924-8424
Huang, Yuanlong0000-0002-6726-8904
Schulze, Benjamin C.0000-0002-6405-8872
Kenseth, Christopher M.0000-0003-3188-2336
Ward, Ryan X.0000-0003-2317-3310
Seinfeld, John H.0000-0003-1344-4068
Hering, Susanne V.0000-0001-6536-310X
Flagan, Richard C.0000-0001-5690-770X
Additional Information:© Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Published by Copernicus Publications on behalf of the European Geosciences Union. Received: 28 February 2021 – Discussion started: 8 March 2021; Revised: 20 May 2021 – Accepted: 24 May 2021 – Published: 18 June 2021. The authors gratefully acknowledge support by the U.S. Department of Energy, Office of Science, and by the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. This research has been supported by the U.S. Department of Energy (grant no. DE-SC0013152) and the U.S. Department of Health and Human Services (grant no. OH010515). Review statement: This paper was edited by Francis Pope and reviewed by three anonymous referees. Code availability: The code used for data analysis in this work can be made available upon request from the authors. Data availability: The Spider DMA and LDMA measurement data can be accessed from the Caltech data repository: (Amanatidis et al., 2021b) Video supplement: This video supplement shows the evolution of the ambient aerosol size distribution in Pasadena, CA between 16 May–11 June 2020, as measured by the Spider DMA and LDMA systems (, Amanatidis et al., 2021a).​​​​​​​ Supplement: The supplement related to this article is available online at: Author contributions: SA performed the finite-element modeling for the Spider DMA instrument, analyzed its measurement data, generated the figures, and wrote the manuscript text. YH analyzed the LDMA instrument data and prepared the experimental setup. BP, BCS, CMK, and RXW collected the measurement data and provided technical maintenance to the instruments. JHS reviewed and provided editorial feedback on the manuscript. SVH and RCF planned the experiments and contributed to interpretation of the results and editing of the manuscript. Competing interests: Richard C. Flagan and Stavros Amanatidis are inventors of the “Spider” DMA technology patent (US10775290B2), which is licensed to Susanne V. Hering's company. The rest of the authors declare that they have no conflict of interest. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0013152
Department of Health and Human ServicesOH010515
Issue or Number:6
Record Number:CaltechAUTHORS:20210727-171444056
Persistent URL:
Official Citation:Amanatidis​​​​​​​, S., Huang, Y., Pushpawela, B., Schulze, B. C., Kenseth, C. M., Ward, R. X., Seinfeld, J. H., Hering, S. V., and Flagan, R. C.: Efficacy of a portable, moderate-resolution, fast-scanning differential mobility analyzer for ambient aerosol size distribution measurements, Atmos. Meas. Tech., 14, 4507–4516,, 2021
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110026
Deposited By: Tony Diaz
Deposited On:02 Aug 2021 17:30
Last Modified:02 Aug 2021 17:30

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