• Journal of Korean Society for Atmospheric Environment
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• v.33 no.2
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• pp.77-86
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• 2017

Globally, use of affordable fuels such as briquettes, woods and wood pellets has increased. Organic pollutants emitted from non-point sources using solid fuels may have contributed to air pollution in urban environment. In this study, we utilized simulated incinerator proposed by U.S. EPA and investigated concentrations of PM, $PM_{10}$, $PM_{2.5}$, OC/EC, CO, $SO_x$, $NO_x$, VOCs and PAHs emitted while cooking meat and fish using briquettes, woods and wood pellets, and developed emission factors. As a result, wood combustion produced more air pollutants than the others. Particulate matter emission factors for woods and wood pellets were 13.54 g/kg and 9.15 g/kg, respectively. Total VOCs emission factors for briquettes, woods and wood pellets were 36.12mg/kg, 46.13mg/kg and 18.26mg/kg, respectively. Additionally, total PAHs emission factors for briquette, woods and wood pellets were 0.44 mg/kg, 18.84mg/kg and 101.62mg/kg, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.259-268
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• 2005

In this study, we investigated the seasonal variations in the composition and emission patterns of VOC ventilated as landfill gas (LFG) from an urban municipal landfill site during the winter (2002) and summer (2003) period. The results of our study, when examined using the major aromatic VOC components as BTEX, indicated the existence of diverse characteristics in the LFG emissions of VOC. It was found that the relative extent of benzene emission showed most significant increase in the summer season, while most species underwent notable reductions. Despite the presence of certain patterns in the seasonal emissions of BTEX, the gross picture of their emission between summer and winter was not different distinctively so that the wintertime emissions exceed their summer counterparts by about three times. The observations of moderate enhancement in wintertime LFG emissions of BTEX appeared to reflect such environmental changes in the winter season as favorable conditions for LFG ventilation with reduced surface emissions due to frozen soil layers.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.215-226
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• 2005

In this study, we investigated the emission concentrations of 31 odorous compounds from various emission sources of 37 individual companies located within the Ban Wal industrial complex of Ansan city, Korea. In the course of our study, we attempted to evaluate emission characteristics of different industrial activities and relative significance of different odorous components . Based on our measurements of odorous compounds, we were able to find a line of evidence to draw a conclusion that a number of odorous compounds can be used as indices to specifically point out the influence of certain industrial activities. It was found that hydrogen sulfide and trimethyl amine record the highest contribution from leather industry. Likewise, acetaldehyde showed its maximum contribution from food-beverage sector, while ammonia for paper-mill, pulp production sector. On the other hand, the results of styrene and most YOC including BTEX were not useful, as their concentrations were not significantly high enough to judge from such respect.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.311-318
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• 2015

Emission characteristics from charbroiling of four different meats (beef, port, duck and chicken) in a pilot-scale cooking facility were investigated in this study. The analyzed air pollutants include gaseous species (CO, NO, $SO_2$, $NH_3$ and PAHs) as well as particulate matters (TSP, $PM_{10}$, $PM_{2.5}$ and black carbon). The emission factors of $PM_{10}$ and PAHs were in the range of 3~47 g-PM/kg-meat and 0.6~11.41 mg-PAHs/kg-meat, respectively, depending on the type of a meat. In addition, the results also revealed that the high ratio of $PM_{2.5}$ to TSP in a meat charbroiling should be considered to design and to operate air pollution control devices.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.5
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• pp.538-555
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• 2012

The purpose of this study was to understand $PM_{2.5}$ chemical characteristics on the Suwon/Yongin area and further to quantitatively estimate $PM_{2.5}$ source contributions. The $PM_{2.5}$ sampling was carried out by a high-volume air sampler at the Kyung Hee University-Global Campus from November, 2010 to October, 2011. The 40 chemical species were then analyzed by using ICP-AES(Ag, Ba, Cr, Cu, Fe, Mn, Ni, Pb, Si, Ti, V and Zn), IC ($Na^+$, $K^+$, $NH_4{^+}$, $Mg^{2+}$, $Ca^{2+}$, $NO_3{^-}$, ${SO_4}^{2-}$ and $Cl^-$), DRI/OGC (OC1, OC2, OC3, OC4, OP, EC1, EC2 and EC3) and GC-FID (acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[a] pyrene, indeno[1,2,3-cd] pyrene, benzo[g,h,i]perylene and dibenzo[a,h,]anthracene). When applying PMF model after performing proper data treatment, a total of 10 sources was identified and their contributions were quantitatively estimated. The average contribution to $PM_{2.5}$ emitted from each source was determined as follows; 26.3% from secondary aerosol source, 15.5% from soil and road dust emission, 15.3% from vehicle emission, 15.3% from illegal biomass burning, 12.2% from incineration, 7.2% from oil combustion source, 4.9% from industrial related source, and finally 3.2% from coal combustion source. In this study we used the ratios of PAHs concentration as markers to double check whether the sources were reasonably classified or not. Finally we provided basic information on the major $PM_{2.5}$ sources in order to improve the air quality in the study area.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.243-251
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• 2011

BACKGROUND: Gypsum($CaSO_4{\cdot}2H_2O$) is known as an ideal amendment to improve soil quality of the reclaimed coastal land. Since gypsum has very high concentration of electron acceptor like ${SO_4}^{2-}$, its application might be effective on reducing $CH_4$ emission during rice cultivation, but its effect has not been studied well. METHODS AND RESULTS: The effect of gypsum on $CH_4$ emission and rice growth characteristics was studied by pot test, which was packed by reclaimed paddy soils collected from Galsa, Hadong, Gyeongnam province. Chemical-grade gypsum was applied in two soils having EC 2.25 and 9.48 dS/m at rates of 0, 0.5, 1.0 and 2.0%(wt/wt). $CH_4$ emission was characterized a week interval by closed chamber method during rice cultivation. $CH_4$ emission rate was significantly decreased with increasing salt accumulation and gypsum application levels. With increasing gypsum application, dissolved ${SO_4}^{2-}$ concentration in the leachate water was significantly increased, which might have suppressed $CH_4$ production in soil. Total $CH_4$ flux was dramatically decreased with increasing gypsum application. In contrast, rice yield was increased with increasing gypsum application and then achieved maximum productivity at 1.0% gypsum application in two soils. CONCLUSION(s): Gypsum is a very good soil amendment to suppress $CH_4$ emission in reclaimed coastal paddy soils, and improve rice productivity and soil properties. The optimum application level of gypsum is assumed at ca. 1% to improve soil productivity with reducing effectively $CH_4$ emission during rice cultivation.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.1
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• pp.33-41
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• 1998

The response characteristics of the PZT transducers during glass capillary breakage were studied at the epicenter of the glass plate. The PZT transducers had been made by using EC-65 PZT ceramics(supplied by Edo co.) with a constant area and a various thickness. The theoretical displacement and velocity at the epicenter of glass plate with an air boundary condition were calculated by assuming the point load of 1N force strength and a rise time of 280 ns with a ramped functional dependence, and the 1st pulses of the PZT transducer may be considered as the vertical velocity incident on the electrode of the PZT ceramic. The responses of the PZT transducer may be depended on the thickness mode of the PZT ceramic below 0.33 in the ratio of the thickness to the diameter of PZT ceramic, but the reponse of the PZT transducer may be depended on the other modes of PZT transducer in the addition of the thickness mode of the PZT ceramic above 0.33. The full time of half maximum at the 1st pulse was nearly 280 ns without a variation of applied breakage load and the resonant frequency of the PZT transducer, and then may be considered as the rise time of a AE source. The maximum amplitude of the 1st pulse depended on the incident vertical velocity and capacitance of the PZT transducer. Therefore, the full time of half maximum and maximum amplitude of the 1st pulse may be considered as the rise time and strength of acoustic emission source respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.3
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• pp.25-32
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• 2022

To understand the distribution characteristics of PM_2.5 concentration in the Saemangeum Reclamation Area and nearby areas, three points of the background area, the occurrence area, and the affected area were selected and samples were collected for each season. The chemical composition was determined. As a result of analyzing the chemical composition contained in PM_2.5, NO₃^- (7.2 ㎍/m³), SO₄^2- (4.3 ㎍/m³), NH₄+ (4.3 ㎍/m³), OC (2.5 ㎍/m³), Si (1.3 ㎍/m³) m³) and EC (0.5 ㎍/m³) seemed to be the main components, and NO₃-, SO₄^2-, NH₄⁺, which are components that form secondary particles, occupied a large proportion. The composition ratio of PM_2.5 was investigated in the order of ion component (56.8%) > Unknown (27.4%) > carbon component (11.8%) > heavy metal component (4.0%). During the PM_2.5 high concentration case days, the ionic component accounted for 90.7% during atmospheric stagnation cases, whereas the chemical composition ratio was in the order of ionic component (51.7%) > heavy metal component (41.5%) > carbon component (6.8%) during yellow dust cases. It was found that the characteristic of PM_2.5 in the Saemangeum reclaimed land and surrounding areas is mainly influenced by outside (domestic and overseas) throughout the year. Ion components accounted for the largest portion of PM_2.5 components in this area, but there were few sources of SOx and NOx emission in the Seamangeum area, which are precursors for secondary particle formation. Therefore, it is judged that most of these are generated and influenced as a secondary reaction in the atmosphere from the outside.

• Journal of Environmental Science International
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• v.32 no.4
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• pp.205-220
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• 2023

In this study, impact of the COVID-19 outbreak on PM_2.5 mass and its five chemical components (NH₄⁺, NO₃^-, SO₄^2-, OC, EC) in Busan was evaluated, and compared with that of Seoul. The study period over the recent three years was sub-divided into two periods: Pre-COVID (2018~2019) and COVID (2020) periods, and the differences in observed annual and monthly variations between the two periods were explored here. The results indicated that annual mean PM_2.5 mass concentrations decreased during the COVID period by 16% in Seoul and 29% in Busan, and the satellite-observed annual average of aerosol optical depth (AOD) over the Korean Peninsula also decreased by approximately more than 10% compared with that of the Pre-COVID period. All of the five chemical components decreased but no particular changes were found in their fractions occupied during the COVID period. However, over the Lock-down period (2020-March), the sulfate fraction decreased in Seoul, mostly reflecting the recent Chinese trends of aerosol characteristics, whereas the nitrate fraction considerably decreased in Busan, which was attributable to the local emission changes and their variabilities in Busan. Other meteorological characteristics such as higher frequencies of easterly winds in the Busan area during the COVID period were also discussed in comparison with those in the Seoul area.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.1-9
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• 2020

Objectives: The purpose of this case study is to assess workers' exposure to carbon nanotubes(CNTs) and characterize particles aerosolized during the process of producing CNT-enabled polytetrafuoroethylene(PTFE) composites at a worksite in Korea. Methods: Personal breathing zone and area samples were collected for determining respirable concentrations of elemental carbon(EC) using NIOSH(National Institute for Occupational Safety and Health) Method 5040. Personal exposure to nano-sized particles was measured as the number concentration and mean diameter using personal ultrafine particle monitors. The number concentration by particle size was measured using optical particle sizers(OPS) and scanning mobility particle sizers(SMPS). Transmission electron microscopy (TEM) area samples were collected on TEM grids and analyzed to characterize the size, morphology, and chemistry of the particles. Results: Respirable EC concentrations ranged from 0.04 to 0.24 ㎍/㎥, which were below 23% of the exposure limit recommended by NIOSH and lower than background concentrations. Number concentrations by particle size measured using OPS and SMPS were not noticeably elevated during CNT-PTFE composite work. Instant increase of number concentrations of nano-sized particles was observed during manual sanding of CNT-PTFE composites. Both number concentrations and mean diameters did not show a statistically significant difference between workers handing CNT-added and not-added materials. TEM analyses revealed the emission of free-standing CNTs and CNT-PTFE aggregate particles from the powder supply task and composite particles embedded with CNTs from the computer numerical control(CNC) machining task with more than tens of micrometers in diameter. No free-standing CNT particles were observed from the CNC machining task. Conclusions: Significant worker exposure to respirable CNTs was not found, but the aerosolization of CNTs and CNT-embedded composite particles were observed during handing of CNT-PTFE powders and CNC machining of CNT-PTFE composites. Considering the limited knowledge on the toxicity of CNTs and CNT composite particles to date, it seems prudent to take a precautionary approach for the protection of workers' health.