Publications by authors named "Jong-Sang Youn"

13 Publications

  • Page 1 of 1

Relationship between Cytotoxicity and Surface Oxidation of Artificial Black Carbon.

Nanomaterials (Basel) 2021 May 31;11(6). Epub 2021 May 31.

Department of Environmental Engineering, Inha University, Incheon 22212, Korea.

The lacking of laboratory black carbon (BC) samples have long challenged the corresponding toxicological research; furthermore, the toxicity tests of engineered carbon nanoparticles were unable to reflect atmospheric BC. As a simplified approach, we have synthesized artificial BC (aBC) for the purpose of representing atmospheric BC. Surface chemical properties of aBC were controlled by thermal treatment, without transforming its physical characteristics; thus, we were able to examine the toxicological effects on A549 human lung cells arising from aBC with varying oxidation surface properties. X-ray photoelectron spectroscopy, as well as Raman and Fourier transform infrared spectroscopy, verified the presence of increased amounts of oxygenated functional groups on the surface of thermally-treated aBC, indicating aBC oxidization at elevated temperatures; aBC with increased oxygen functional group content displayed increased toxicity to A549 cells, specifically by decreasing cell viability to 45% and elevating reactive oxygen species levels up to 294% for samples treated at 800 °C.
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http://dx.doi.org/10.3390/nano11061455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229741PMC
May 2021

Hygroscopic and Chemical Properties of Aerosol Emissions at a Major Mining Facility in Iran: Implications for Respiratory Deposition.

Atmos Pollut Res 2021 Mar 11;12(3):292-301. Epub 2021 Jan 11.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.

This study characterizes the hygroscopic and chemical nature of aerosols originating from ten locations (4 outdoors and 6 indoors) around the Gol-E-Gohar (GEG) iron ore mine (Iran), including an assessment of how hygroscopic growth alters particulate deposition in the respiratory system. Aerosols collected on filters in three diameter (D) ranges (total suspended particulates [TSP], D ≤ 10 μm [PM], and D ≤ 2.5 μm [PM]) were analyzed for chemical and hygroscopic characteristics. The water-soluble aerosol composition is dominated by species associated with directly emitted crustal matter such as chloride, sodium, calcium, and sulfate. There was minimal contribution from organic acids and other secondarily formed species such as inorganic salts. Aerosol growth factors at 90% relative humidity varied between 1.39 and 1.72 and exceed values reported for copper mines in the United States where similar data are available. Values of the hygroscopicity parameter kappa (0.19 to 0.45) were best related to the mass fraction of chloride among all the studied species. Kappa values were generally similar when comparing the three types of samples (TSP, PM, PM) at each site and also when comparing each of the ten sampling sites. Accounting for hygroscopic growth yields an increase in the deposition fraction for aerosols with a dry D between 0.2 and 2 μm based on International Commission on Radiological Protection model calculations, with more variability when examining each of the three individual head airway regions.
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http://dx.doi.org/10.1016/j.apr.2020.12.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117051PMC
March 2021

Quantification of tire wear particles in road dust from industrial and residential areas in Seoul, Korea.

Sci Total Environ 2021 Aug 18;784:147177. Epub 2021 Apr 18.

Department of Environmental Engineering, Inha University, Incheon 22212, Republic of Korea; Program in Environmental and Polymer Engineering, Inha University, Incheon 22212, Republic of Korea. Electronic address:

In this study, we examined tire and road wear microparticles (TRWMPs) in road dust along the Seoul metropolitan area, from industrial and residential areas. The road dust samples were collected via vacuum sweep methods and then filtered to obtain particles with diameters less than 75 μm. To quantify the TRWMPs in road dust, we used the raw materials of tire components, natural rubber (NR), and styrene-butadiene rubber (SBR), as standard materials. We evaluated the usability of the pyrolyzer-gas chromatography/mass spectrometry py-GC/MS method introduced in ISO/TS 20593 by confirming the decomposition temperatures of the NR and SBR by thermogravimetric (TG) and evolved gas analysis (EGA)-MS. The average of TRWMPs in industrial and residential area road dust were 22,581 and 9818 μg/g, respectively, indicating that the industrial area has 2.5 times higher TRWMPs concentration. Further, the NR, the main component of truck bus radial, to SBR, the main component of passenger car radial, ratio was slightly higher in the industrial area than in the residential area. This presumably means that the high traffic volume, including heavy duty vehicles in industrial areas, affected the higher concentration of TRWMPs. This study reveals the growing evidence of the importance of TRWMPs in road dust and how TRWMPs quantity can impact the air quality of the Seoul metropolitan area.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147177DOI Listing
August 2021

Pd Nanocluster/Monolayer MoS Heterojunctions for Light-Induced Room-Temperature Hydrogen Sensing.

ACS Appl Mater Interfaces 2021 Mar 16;13(12):14644-14652. Epub 2021 Mar 16.

Department of Environmental Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon 22212, Republic of Korea.

Developing sensing approaches that can exploit visible light for the detection of low-concentration hydrogen at room temperatures has become increasingly important for the safe use of hydrogen in many applications. In this study, heterostructures composed of monolayer MoS and Pd nanoclusters (Pd/MoS) acting as photo- and hydrogen-sensitizers are successfully fabricated in a facile and scalable manner. The uniform deposition of morphologically isotropic Pd nanoclusters (11.5 ± 2.2 nm) on monolayer MoS produces a plethora of active heterojunctions, effectively suppressing charge carrier recombination under light illumination. The dual photo- and hydrogen-sensitizing functionality of Pd/MoS can enable its use as an active sensing layer in optoelectronic hydrogen sensors. Gas-sensing examinations reveal that the sensing performance of Pd/MoS is enhanced three-fold under visible light illumination (17% for 140 ppm of H) in comparison with dark light (5% for 140 ppm of H). Photoactivation is also found to enable excellent sensing reversibility and reproducibility in the obtained sensor. As a proof-of-concept, the integration of Pd nanoclusters and monolayer MoS can open a new avenue for light-induced hydrogen gas sensing at room temperature.
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http://dx.doi.org/10.1021/acsami.0c20475DOI Listing
March 2021

Development of PM and PM cyclones for small sampling ports at stationary sources: Numerical and experimental study.

Environ Res 2021 02 24;193:110507. Epub 2020 Nov 24.

Department of Environmental Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea. Electronic address:

Air pollution caused by particulate matter (PM) has become a serious issue, and significant research has focused on managing large stationary emission sources, i.e., the primary sources of PM. Currently, the U.S. Environmental Protection Agency (EPA) Method 201A and ISO 23210 are predominantly employed to measure the PM emissions at large stationary sources. Method 201A is designated as a standard test method in Korea, but it is difficult to measure PM and PM simultaneously owing to the size of the full-set cyclone. In large stationary emission sources, the use of a serial connection of PM and PM cyclones is unsuitable for measurements at conventional sampling ports featuring diameters of approximately 100 mm. Therefore, in this study, PM and PM cyclones were developed to replace the cyclones currently used in Method 201A. The developed cyclones featured a cutoff diameter, which was confirmed by numerical and experimental analyses that were close to Method 201A. Moreover, there was an increase in the stiffness of collection efficiency. The hook adaptor, which is a key accessory used in Method 201A, was found to be applicable to the newly developed cyclones. This alternative method will help reduce the measurement time by simultaneously measuring TSP, PM, and PM and eliminates the costs of installing or refurbishing additional sampling ports at existing large stationary sources.
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http://dx.doi.org/10.1016/j.envres.2020.110507DOI Listing
February 2021

Prediction Model for Dry Eye Syndrome Incidence Rate Using Air Pollutants and Meteorological Factors in South Korea: Analysis of Sub-Region Deviations.

Int J Environ Res Public Health 2020 07 10;17(14). Epub 2020 Jul 10.

Department of Environmental Engineering, Inha University, Incheon 22212, Korea.

Here, we develop a dry eye syndrome (DES) incidence rate prediction model using air pollutants (PM, NO, SO, O, and CO), meteorological factors (temperature, humidity, and wind speed), population rate, and clinical data for South Korea. The prediction model is well fitted to the incidence rate (R = 0.9443 and 0.9388, < 2.2 × 10). To analyze regional deviations, we classify outpatient data, air pollutant, and meteorological factors in 16 administrative districts (seven metropolitan areas and nine states). Our results confirm NO and relative humidity are the factors impacting regional deviations in the prediction model.
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http://dx.doi.org/10.3390/ijerph17144969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399894PMC
July 2020

A new air-washing method to clean fabric filters clogged with submicron fume particles: A pilot-scale study.

J Hazard Mater 2020 02 9;383:121186. Epub 2019 Sep 9.

Department of Environmental Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea. Electronic address:

This study investigates a new air-washing cleaning system that directly injects compressed air on the filter surface for filter regeneration in a fabric filter (FF) dust collector. A pilot-scale FF is designed to test the new system and to compare it with the conventional pulse-jet cleaning system with regard to filter clogging by fume particles. A pleated filter with a filtration area of 2.4 m is installed in the FF and a thermal steel spraying gun is used to supply the fume particles. Pressure drop and particle emission concentration are monitored to examine the effect of the new system on filter regeneration and collection efficiency. The results show that the air-washing cleaning is effective for filter regeneration, as it allows the FF to operate stably for a long time, whereas the pulse-jet cleaning fails to achieve filter regeneration, resulting in a continuously increasing pressure drop. In addition, air-washing cleaning shows better performance on collection efficiency than the pulse-jet cleaning method, as it reduces the outlet particulate matter concentration to less than half that of the pulse-jet cleaning.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121186DOI Listing
February 2020

Study of stainless steel electrodes after electrochemical analysis in sea water condition.

Environ Res 2019 06 30;173:549-555. Epub 2019 Mar 30.

Department of Environmental Engineering, Inha University, Incheon, 22212, Republic of Korea. Electronic address:

For water electrolysis, a rare earth material (eg., platinum) is often used as an electrode, but because of the high cost and toxicity of chemicals, researchers are searching for cost effective and eco-friendly alternative materials. Various alloys and metals have been long explored for use as electrode materials in different media. Stainless steel (SS 304) electrodes are cost effective and have a large surface area; further their catalytic performance is comparable to that of carbon coated noble metals cathodes. Stainless steel has good mechanical properties and durability so it is widely used in desalination plants, oil and gas industries, ship building, etc. However, over a period of time it corrodes very quickly in saline water. To improve the stability and durability of the electrodes (i.e., to minimize corrosion), we anneal the samples under two different sets of conditions and test the electrodes in 3.5% NaCl solution. The anodic peak (-0.25 V) observed for bare stainless steel result from the formation of iron (II) hydroxide [Fe(OH)]. The Raman bands observed at 210 and 274 cm for bare stainless steel result from the formation of α-FeO owing to partial, anodic, and cathodic reactions occurring on the electrode which disrupts the surface layers. High intensity X-ray diffraction (XRD) and Raman peaks of CrO and MnCrO observed in argon and hydrogen annealed sample after cyclic voltammetry reveal that this sample is more stable than bare and air annealed samples. XRD reveals mixed oxide phases in addition to eskolaite and magnetite phases. Scanning electron microscope (SEM) images show that although the air-annealed sample has a soft, spongy structure, Na and Cl ions are adsorbed in the voids on the outer surface of the electrode leading to quick degradation. For the air-annealed sample the oxide appears to adhere poorly to the stainless steel. Oxygen (ie., oxide composition) may play a key role in adherence and growth of CrO formed at high temperature. X-ray photoelectron spectroscopy (XPS) reveals that large amounts of Cr and Mn are dissolved/corroded into the electrolyte for air annealed sample which is in good agreement with the Raman and SEM results.
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http://dx.doi.org/10.1016/j.envres.2019.03.069DOI Listing
June 2019

Determination of the emission rate for ultrafine and accumulation mode particles as a function of time during the pan-frying of fish.

J Environ Manage 2019 Apr 1;236:75-80. Epub 2019 Feb 1.

Department of Environmental Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon, 22212, Republic of Korea. Electronic address:

Particulate matter (PM) from cooking is considered one of the most harmful indoor air pollutants causing numerous adverse health effects, and it is essential to comprehend the characteristics of the particles generated from cooking to prevent these problems. In this study, we investigated PM from the pan-frying of salmon using number concentration and developed emission rates as a function of time for ultrafine particles (UFPs < 100 nm) and accumulation mode particles (AMPs 0.1-1 μm). The newly defined emission rates vary significantly with time and are very different from the conventionally determined rates that do not consider the variation of particle concentration with time. The emission rate of UFPs decreased over time after a sharp rise, whereas that of AMPs continued to increase, resulting in a change in the proportions of UFPs and AMPs in the total PM from 93 to 7% to 72 and 28%, respectively. Particle-particle interactions such as coagulation and coalescence were observed between primary particles via high resolution transmission electron microscopy (HR-TEM), which is a plausible reason for the decreasing emission rate of UFPs with time. The emission rate as a function of time can serve as a tool to estimate PM from cooking, as well as to monitor the change trends through phenomena such as agglomeration.
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http://dx.doi.org/10.1016/j.jenvman.2018.12.010DOI Listing
April 2019

Development of a Conjunctivitis Outpatient Rate Prediction Model Incorporating Ambient Ozone and Meteorological Factors in South Korea.

Front Pharmacol 2018 9;9:1135. Epub 2018 Oct 9.

Department of Ophthalmology and Visual Science, Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, South Korea.

Ozone (O) is a commonly known air pollutant that causes adverse health effects. This study developed a multi-level prediction model for conjunctivitis in outpatients due to exposure to O by using 3 years of ambient O data, meteorological data, and hospital data in Seoul, South Korea. We confirmed that the rate of conjunctivitis in outpatients (conjunctivitis outpatient rate) was highly correlated with O ( = 0.49), temperature ( = 0.72), and relative humidity ( = 0.29). A multi-level regression model for the conjunctivitis outpatient rate was well-developed, on the basis of sex and age, by adding statistical factors. This model will contribute to the prediction of conjunctivitis outpatient rate for each sex and age, using O and meteorological data.
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http://dx.doi.org/10.3389/fphar.2018.01135DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6189411PMC
October 2018

Hygroscopic Properties and Respiratory System Deposition Behavior of Particulate Matter Emitted By Mining and Smelting Operations.

Environ Sci Technol 2016 11 13;50(21):11706-11713. Epub 2016 Oct 13.

Mel and Enid Zuckerman College of Public Health, University of Arizona , Tucson, Arizona 85724, United States.

This study examines size-resolved physicochemical data for particles sampled near mining and smelting operations and a background urban site in Arizona with a focus on how hygroscopic growth impacts particle deposition behavior. Particles with aerodynamic diameters between 0.056-18 μm were collected at three sites: (i) an active smelter operation in Hayden, AZ, (ii) a legacy mining site with extensive mine tailings in Iron King, AZ, and (iii) an urban site, inner-city Tucson, AZ. Mass size distributions of As and Pb exhibit bimodal profiles with a dominant peak between 0.32 and 0.56 μm and a smaller mode in the coarse range (>3 μm). The hygroscopicity profile did not exhibit the same peaks owing to dependence on other chemical constituents. Submicrometer particles were generally more hygroscopic than supermicrometer ones at all three sites with finite water-uptake ability at all sites and particle sizes examined. Model calculations at a relative humidity of 99.5% reveal significant respiratory system particle deposition enhancements at sizes with the largest concentrations of toxic contaminants. Between dry diameters of 0.32 and 0.56 μm, for instance, ICRP and MPPD models predict deposition fraction enhancements of 171%-261% and 33%-63%, respectively, at the three sites.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5089925PMC
http://dx.doi.org/10.1021/acs.est.6b03621DOI Listing
November 2016

Surface and Airborne Measurements of Organosulfur and Methanesulfonate Over the Western United States and Coastal Areas.

J Geophys Res Atmos 2015 Aug;120(16):8535-8548

Center for Interdisciplinary Remotely Piloted Aircraft Studies, Naval Postgraduate School, Monterey, CA, United States.

This study reports on ambient measurements of organosulfur (OS) and methanesulfonate (MSA) over the western United States and coastal areas. Particulate OS levels are highest in summertime, and generally increase as a function of sulfate (a precursor) and sodium (a marine tracer) with peak levels at coastal sites. The ratio of OS to total sulfur (TS) is also highest at coastal sites, with increasing values as a function of Normalized Difference Vegetation Index (NDVI) and the ratio of organic carbon to elemental carbon. Correlative analysis points to significant relationships between OS and biogenic emissions from marine and continental sources, factors that coincide with secondary production, and vanadium due to a suspected catalytic role. A major OS species, methanesulfonate (MSA), was examined with intensive field measurements and the resulting data support the case for vanadium's catalytic influence. Mass size distributions reveal a dominant MSA peak between aerodynamic diameters of 0.32-0.56 μm at a desert and coastal site with nearly all MSA mass (≥ 84%) in sub-micrometer sizes; MSA:non-sea salt sulfate ratios vary widely as a function of particle size and proximity to the ocean. Airborne data indicate that relative to the marine boundary layer, particulate MSA levels are enhanced in urban and agricultural areas, and also the free troposphere when impacted by biomass burning. Some combination of fires and marine-derived emissions leads to higher MSA levels than either source alone. Finally, MSA differences in cloud water and out-of-cloud aerosol are discussed.
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http://dx.doi.org/10.1002/2015JD023822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4581448PMC
August 2015

Evidence of aqueous secondary organic aerosol formation from biogenic emissions in the North American Sonoran Desert.

Geophys Res Lett 2013 Jul;40(13):3468-3472

Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA.

This study examines the role of aqueous secondary organic aerosol formation in the North American Sonoran Desert as a result of intense solar radiation, enhanced moisture, and biogenic volatile organic compounds (BVOCs). The ratio of water-soluble organic carbon (WSOC) to organic carbon (OC) nearly doubles during the monsoon season relative to other seasons of the year. When normalized by mixing height, the WSOC enhancement during monsoon months relative to preceding dry months (May-June) exceeds that of sulfate by nearly a factor of 10. WSOC:OC and WSOC are most strongly correlated with moisture parameters, temperature, and concentrations of O and BVOCs. No positive relationship was identified between WSOC or WSOC:OC and anthropogenic tracers such as CO over a full year. This study points at the need for further work to understand the effect of BVOCs and moisture in altering aerosol properties in understudied desert regions.
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http://dx.doi.org/10.1002/grl.50644DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792583PMC
July 2013
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