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Development of a magnetic hybrid filter to reduce PM10 in a subway platform
Son, Youn-Suk,Oh, Yong-Hwan,Choi, In-Young,Dinh, Trieu-Vuong,Chung, Sang-Gwi,Lee, Jai-hyo,Park, Duckshin,Kim, Jo-Chun Elsevier 2019 Journal of hazardous materials Vol.368 No.-
<P><B>Abstract</B></P> <P>This study investigated the reduction of particulate matter (PM) in a subway platform using self-developed magnetic hybrid filters (magnet-magnet (MM) and magnet-cascade (MC) filter). The magnetic hybrid filter systems were installed and operated in Jegi-dong subway station (J station) platform. The removal efficiency of PM<SUB>10</SUB> (particular matter with aerodynamic diameter less than 10 μm) was evaluated according to various influencing factors such as the combination of filters, linear velocity, and operating conditions of trains. As a result, the average removal efficiency of the MC filter (40.5%) was higher than that of the MM one (27.0%). The maximum PM<SUB>10</SUB> removal efficiencies by MM (34.1%) and MC (47.2%) filters were observed at 20 (linear velocity: 2.41 m/s) and 30 jog (8 m/s) dials, respectively. We additionally found that the removal efficiency of PM<SUB>10</SUB> using MM and MC filters suddenly decreased when the concentration of background PM<SUB>10</SUB> in the platform increased. Based on the results of this study, hybrid technology using two or more capture principles can remove PM more efficiently than technology using a single such principle.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Magnetic hybrid filters were developed to reduce PM10 in a subway system. </LI> <LI> Removal efficiencies of the MC filter were higher than that of the MM filter. </LI> <LI> The removal efficiency decreased when the concentration of PM10 was increased. </LI> <LI> Most of iron particulates can be removed using the MC filter system. </LI> </UL> </P>
Son, Youn-Suk,Salama, Amgad,Jeong, Hye-Seon,Kim, Suhyang,Jeong, Jin-Ho,Lee, Jaihyo,SunWoo, Young,Kim, Jo-Chun Korean Society for Atmospheric Environment 2013 Asian Journal of Atmospheric Environment (AJAE) Vol.7 No.1
$PM_{10}$ concentrations were measured at four monitoring sites at the Daechaung station of the Seoul subway. The four locations included two tunnels, a platform, and a waiting room. The outside site of the subway was also monitored for comparison purposes. In addition, the effect of the platform screen doors (PSDs) recently installed to isolate the $PM_{10}$ in a platform from a tunnel were evaluated, and a comparison between $PM_{10}$ levels during rush and non-rush hours was performed. It was observed that $PM_{10}$ levels in the tunnels were generally higher than those in the other locations. This might be associated with the generation of $PM_{10}$ within the tunnel due to the train braking and wear of the subway lines with the motion of the trains, which promotes the mixing and suspension of particulate matter. During this tunnel study, it was observed that the particle size of $PM_{10}$ ranged from 1.8 to 5.6 ${\mu}m$. It was revealed that the $PM_{10}$ levels in the tunnels were significantly increased by the PSDs, while those in the platform and waiting room decreased. As a result, in order to estimate the effect of ventilation system on $PM_{10}$ levels in the tunnels, fans with inverters were operated. It was found that the concentration of $PM_{10}$ was below 150 ${\mu}g/m^3$ when the air flow rate into a tunnel was approximately 210,000-216,000 CMH.
Control factors and by-products during decomposition of butane in electron beam irradiation
Son, Youn-Suk,Park, Kang-Nam,Kim, Jo-Chun Elsevier 2010 Radiation physics and chemistry Vol.79 No.12
<P><B>Abstract</B></P><P>This research was conducted to determine the removal characteristics of butane, using an electron beam. Influential factors, such as an initial concentration, background gases (nitrogen, air, and helium), and absorbed doses (kGy) were investigated. The decomposition efficiencies of background gases showed that oxidation caused by radicals formed from gases, such as N<SUB>2</SUB> and O<SUB>2</SUB>, had a greater influence on results than oxidation from primary electrons for butane removal. Removal efficiencies were 40% at 2.5kGy and 66% at 10kGy, when the initial concentration of butane was 60ppmC. When the initial concentration was lower, the energy efficiency of butane removal by electron beam was higher. By-products, including CO<SUB>2</SUB>, CO, acetaldehyde, and acetone, formed after electron beam irradiation. Concentrations of CO<SUB>2</SUB> and CO tended to increase when absorbed doses increased as butane was decomposed by the electron beam through an advanced oxidation.</P>
Removal of Particulate Matter Emitted from a Subway Tunnel Using Magnetic Filters
Son, Youn-Suk,Dinh, Trieu-Vuong,Chung, Sang-Gwi,Lee, Jai-hyo,Kim, Jo-Chun American Chemical Society 2014 Environmental science & technology Vol.48 No.5
<P>We removed particulate matter (PM) emitted from a subway tunnel using magnetic filters. A magnetic filter system was installed on the top of a ventilation opening. Magnetic field density was increased by increasing the number of permanent magnet layers to determine PM removal characteristics. Moreover, the fan’s frequency was adjusted from 30 to 60 Hz to investigate the effect of wind velocity on PM removal efficiency. As a result, PM removal efficiency increased as the number of magnetic filters or fan frequency increased. We obtained maximum removal efficiency of PM<SUB>10</SUB> (52%), PM<SUB>2.5</SUB> (46%), and PM<SUB>1</SUB> (38%) at a 60 Hz fan frequency using double magnetic filters. We also found that the stability of the PM removal efficiency by the double filter (RSD, 3.2–5.8%) was higher than that by a single filter (10.9–24.5%) at all fan operating conditions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-5/es404502x/production/images/medium/es-2013-04502x_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es404502x'>ACS Electronic Supporting Info</A></P>
Son, Youn-Suk,Kim, Ki-Joon,Kim, Ji-Yong,Kim, Jo-Chun Elsevier 2010 Radiation physics and chemistry Vol.79 No.12
<P><B>Abstract</B></P><P>We applied a hybrid technique to assess the decomposition characteristics of ethylbenzene and toluene that annexed the catalyst technique with existing electron beam (EB) technology. The removal efficiency of ethylbenzene in the EB–catalyst hybrid turned out to be 30% greater than that of EB-only treatment. We concluded that ethylbenzene was decomposed more easily than toluene by EB irradiation. We compared the independent effects of the EB–catalyst hybrid and catalyst-only methods, and observed that the efficiency of the EB–catalyst hybrid demonstrated approximately 6% improvement for decomposing toluene and 20% improvement for decomposing ethylbenzene. The <I>G</I>-values for ethylbenzene increased with initial concentration and reactor type: for example, the <I>G</I>-values by reactor type at 2800ppmC were 7.5–10.9 (EB-only) and 12.9–25.7 (EB–catalyst hybrid). We also observed a significant decrease in by-products as well as in the removal efficiencies associated with the EB–catalyst hybrid technique.</P>