Supplemental Information

Characterization of an Aerosol Microconcentrator for Analysis Using Microscale Optical Spectroscopies

Lina Zhenga,b, Pramod Kulkarnia*, Konstantinos Zavvosa,b, Huayan Lianga,c M. Eileen Bircha, Dionysios D. Dionysioub

a Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Cincinnati, OH, USA

b Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA

c Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA

Disclaimer—The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Mention of product or company name does not constitute endorsement by the Centers for Disease Control and Prevention.

* Corresponding author: Email: PSKulkarni@cdc.gov; Phone: (513) 841-4300; Fax: (513) 841-4545;

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Fig. S-1. Corona current as a function of voltage applied between two electrodes for different electrode diameters (The distance between two electrodes is 5 mm).

The corona current depends on how high the applied voltage (V) is above the inception value (V0). From Peek’s law, the corona inception voltage decreases with the decreasing electrode diameter, which is attribute to the corresponding field enhancement at the electrode surface. Therefore, the smaller electrode has a lower corona inception voltage. To maintain the same corona current, the applied voltage is lower for a smaller electrode.

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Fig. S-2. The estimated particle mass error (%) for various count median diameter and geometric standard deviation by assuming a constant collection efficiency.

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Fig. S-3. SEM images of the collection electrode at different scales after 5 min for (a) & (b), 10 min for (c) & (d), and 20 min for (e) & (f) of PSL particle collection. (Zavvos, 2016)

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Fig. S-4. SEM images of particle deposition on the electrode flat tip (b) and side walls (c) after 30 min collection. (Zavvos, 2016)

Fig. S-5. (a) A bare collection electrode, (b) A collection electrode with a thin mask of Teflon™ layer wrapped around its side walls. (Zavvos, 2016)

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