Please cite this article in press as: Yang, S., et al. Transient plasma-enhanced remediation of nanoscale particulate matter in restaurant smoke emissions via electrostatic precipitation. Particuology (2020), https://doi.org/10.1016/j.partic.2020.06.003 ARTICLE IN PRESS G Model PARTIC-1356; No. of Pages 5 Particuology xxx (2020) xxx–xxx Contents lists available at ScienceDirect Particuology j our na l ho me page: www.elsevier.com/locate/partic Transient plasma-enhanced remediation of nanoscale particulate matter in restaurant smoke emissions via electrostatic precipitation Sisi Yang a , Patrick Ford d , Sriram Subramanian c , Dan Singleton d , Jason Sanders d , Stephen B. Cronin a,b,d,∗ a Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA b Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA c Daniel J. Epstein Department of Industrial & System Engineering, University of Southern California, Los Angeles, CA 90089, USA d Transient Plasma Systems, Inc., Torrance, CA 90501, USA a r t i c l e i n f o Article history: Received 18 March 2020 Received in revised form 25 May 2020 Accepted 20 June 2020 Available online xxx Keywords: Nanoparticles Transient plasma Charbroiler emission DC bias Remediation a b s t r a c t It is now recognized that nanoscale particulate matter (PM) represents a substantial health hazard for our society, including PM from restaurant smoke. In this study, we explored the use of a transient pulsed plasma in conjunction with an applied DC bias to treat oil aerosols that closely resemble restaurant (i.e., charbroiler) smoke emissions. For polyaromatic olefin PAO-4 and soybean oil, we found that a three- order-of-magnitude reduction in particulates (i.e., 99.9% remediation) could be achieved with this system. Here, the plasma discharge was produced in a 4-in.-diameter cylindrical reactor with a 5–10 ns high voltage (30 kV) pulse generator together with applied DC bias voltages up to 10 kV. The distribution of nanoparticle sizes was measured using a scanning mobility particle sizer (SMPS) with diameter centered around 225 nm. Here, the main mechanism of remediation occurs in a two-step process in which the oil nanoparticles are first ionized by the free electrons and free radicals in the plasma and then the charged particles are swept out to the sidewalls of the reactor by the applied DC potential. We believe this general approach opens up new degrees of freedom in the design of electrostatic oil aerosol pollution control devices. © 2020 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved. Introduction The wide acceptance of the serious health effects associated with nanoscale particulate matter (PM) produced by fossil fuel combustion has led to a wide range of nanotoxicology studies of the environmental emissions from restaurants in commercial cooking processes (e.g., charbroiling) (Chow et al., 2006; Dockery et al., 1993; Kaltsonoudis et al., 2017; McDonald et al., 2003; Oberdörster, Oberdörster, & Oberdörster, 2005; Pope et al., 2002; Samet, Dominici, Curriero, Coursac, & Zeger, 2000; Yancey, Apple, & Wharton, 2016). In 1997, the South Coast Air Quality Manage- ment District (SC-AQMD) in Southern California passed RULE 1138, which regulates PM emissions from chain-driven (i.e., conveyor- belt) charbroilers (Rule 1138, 1997). This PM is made up of oil ∗ Corresponding author at: Ming Hsieh Department of Electrical Engineering, Department of Physics and Astronomy, Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA. E-mail address: scronin@usc.edu (S.B. Cronin). aerosol particles approximately 100–200 nm in size, which are pro- duced from fat-containing meat during the cooking process. In response to this ruling, these chain-driven charbroilers are now outfitted with high temperature oxidation catalysts located just above the hot cooking surface, mitigating these nanometer-scale oil aerosol particles. While chain-driven charbroilers are primar- ily used in large fast-food restaurants, a majority (∼85%) of total restaurant smoke emissions are produced by open underfire char- broilers (Perryman, 2009; Whynot, Quinn, Perryman, & Votlucka, 1999). In a 2016 report, there was an estimated 1400 tons of par- ticulate matter produced annually in New York city originating from these open-underfire charbroilers. According to the Depart- ment of Health and Mental Hygiene, it is estimated that more than 12% of premature deaths due to PM 2.5 (i.e., particles ≤2.5 m) are attributed to open underfire charbroiler emissions (DEP, 2016; New York City Department of Environmental Protection, 2016). By equipping all of the restaurant charbroilers in New York city with effective pollution control technologies, an estimated 88% of these premature deaths can be reduced by limiting the PM 2.5 concentra- tions in the region (DEP, 2016). https://doi.org/10.1016/j.partic.2020.06.003 1674-2001/© 2020 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.