• Journal of Environmental Health Sciences
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• v.49 no.4
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• pp.190-200
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• 2023

Background: Gunsan has been constantly affected by pollutants generated by the Saemangeum development and the construction industry since the completion of the Saemangeum seawall on April 27, 2010. However, there are limitations to its study, such as taking into consideration weather conditions, geographical factors, and foreign inflows. Objectives: In this study, we compared the Existing-CAPSS emissions of Gunsan with Recalculated-CAPSS emissions data to analyze the differences in emissions characteristics by year (2016~2019). Methods: Using Existing data on CAPSS emissions (2016~2019) and Recalculated-CAPSS emissions (2016~2019) for Gunsan, which were Recalculated following the improvement of emissions calculations for 2020, we organized CO, NO_X, SO_X, PM₁₀, VOC_S, and NH₃ emissions by substance and investigated the differences and characteristics of the Recalculated emissions by year. Results: For Re-CO and Re-PM₁₀, the emission characteristics of CO were examined as energy industry combustion and PM₁₀ emission characteristics were examined as ship cargo from non-road transportation sources, as ship leisure sources were excluded from non-road transportation source emissions. Conclusions: Comparing the emissions of Existing-CAPSS and Recalculated-CAPSS in Gunsan, the emissions of Recalculated-CAPSS by substance decreased by 39.76% for CO, 9.98% for PM₁₀, 5.53% for VOC_S, and 9.24% for NH₃, while Re-NO_X increased by 2.86% and Re-SO_X increased by 1.97%. On the other hand, when comparing the emissions characteristics of Existing-CAPSS and Recalculated-CAPSS in Gunsan, Jeonju, and Iksan, the emission characteristics of Re-NO_X, Re-SO_X, Re-VOC_S and Re-NH₃ were similar to those of Ex-NO_X, Ex-SO_X, Ex-VOC_S, and Ex-NH₃. As such, Gunsan, Iksan, and Jeonju, showed differences in the comparison of different emission characteristics due to the geographical characteristics of the region (population, area, topography, weather factors) and the characteristics of the industrial complex (metal, petrochemical).

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.77-85
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• 2004

In this study, the concentrations of reduced S compounds (including hydrogen sulfide (H$_2$S); methyl mercaptan ($CH_3$SH); dimethyl sulfide (($CH_3$)$_2$S); carbon disulfide (CS$_2$); and dimethyl disulfide (($CH_3$)$_2$S$_2$) were determined from landfill gas (LFG) in three municipal landfill sites in the two cities of Gwang Ju (GJ) and Jeju (JJ), Korea. The S gas concentrations measured in these landfill sites were found to be dominated by H$_2$S with its mean concentration of 850 ppm from 10 LFG samples. Both absolute and relative dominance of H$_2$S was seen to be significant in most LFG samples, except those collected from very old and inactive landfills. Unlike the pattern of H$_2$S, other S gases were typically observed at much reduced concentration levels (a few ppm or less) as follows: DMS (3.5); $CH_3$SH (1.3); CS$_2$(1.2); and DMDS (0.02 ppm). If compared equally in mass concentration unit (mg m$^{-3}$ ), H$_2$S generally explained far above 90% of all S gas masses determined concurrently. Moreover, as its mass concentration commonly exceeds those of the major aromatic VOC components in LFG (like benzene and toluene), it appeared to be one of the most dominant gaseous components emitted as LFG in a quantitative sense.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.399-407
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• 2006

In this study, an electrical conductive carbon fiber was used as a biofilter matrix to electrochemically improve the biofilter function. A bioreactor system was composed of carbon fiber (anode), titanium ring, porcelain ring, inorganic nutrient reservoir, and VOC reservoir. Electric DC power of 1.5 volt was charged to the carbon fiber anode (CFA) to induce the electrochemical oxidation potential on the biofilter matrix, but not to the carbon fiber (CF). We tested the effects of electrochemical oxidation potential charged to the CFA on the biofilm structure, the bacterial growth, and the activity for metabolic oxidation of VOCs to $CO_2$, According to the SEM image, the biofilm structure developed in the CFA appeared to be greatly different from that in the CF. The bacterial growth, VOCs degradation, and metabolic oxidation of VOCs to $CO_2$ in the CFA were more activated than those in the CF. On the basis of these results, we propose that the biofilm structure can be improved, and the bacterial growth and the bacterial oxidation activity of VOCs can be activated by the electrochemical oxidation potential charged to a biofilter matrix.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.613-624
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• 2005

In this study, we investigated the characteristic of volatile organic compounds (VOCs) concentrations in Shiwha area, which were measured using the Open-path FTIR Gas Analyzer. The passive samplers were set for a certain period of time to obtain the average concentration of toluene, ethylbenzene, o-xylene and styrene. In addition, VOCs concentration contour maps were constructed using the Tecplot program to illustrate the VOCs concentration distribution. The residential area showed higher concentrations than the industrial area. And the summer had higher concentration value than the winter. Also, we confirmed that the VOCs concentrations ranged from 2 to several tens ppb in the vicinity of an industry than diffused VOC concentration, whereas those ranged from 0 to 5 ppb in most other areas. It was conferred that the wind change with seasons significantly affects the distribution of VOCs concentrations such as a northwesterly wind in the winter or a southwestern wind in the summer.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.244-258
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• 2018

We performed this study to investigate the spatial, seasonal, and daily variations of the concentrations of volatile organic compounds (VOCs) in Pohang, where large steel industrial complexes are located. Ambient air sampling was undertaken at 4 sites during 4 seasons. Each sample was taken for 4 hours continuously for 8 consecutive days per season at each site. Three sites were located within the Pohang city, but one as a control site in Gyeongju. A total of 72 individual VOCs were determined by thermal desorption coupled with GC/MS, including aliphatics, aromatics, carbonyls and halides. The most abundant VOC was toluene, being followed by ethylbenzene and xylenes. Benzene concentrations(c.a. 0.7 ppb) were found to be much lower than the national ambient standard of 1.5 ppb. Overall, the VOCs levels in Pohang appeared to be lower than other national industrial complexes in Korea such as Shiwha-Banwol, Yeosu-Gwangyang, Gumi, and Ulsan. This implies that steel industry may not give significant impacts on the atmospheric levels of VOCs as much as petrochemical, electronic, and/or textile industries, where large amounts of organic solvents are used.

• Asian Journal of Atmospheric Environment
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• v.12 no.2
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• pp.178-191
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• 2018

The concentrations and chemical compositions of volatile organic compounds (VOCs), including volatile fatty acids, phenols, indoles, aldehydes, and ketones, which are the main organic compounds generated by swine, were investigated in July and October 2016 and January 2017. In addition, the emission rates and annual emissions of these components from the swine shed were estimated. The concentrations of VOCs in the swine shed averaged $511.3{\mu}g\;m^{-3}$ in summer, $315.5{\mu}g\;m^{-3}$ in fall and $218.6{\mu}g\;m^{-3}$ in winter. Acetone, acetic acid, propionic acid, and butyric acid were the predominant components of the VOCs, accounting for 80-88% of the total VOCs. The hourly variations of VOC concentrations in the swine shed in fall and winter suggest that the VOC concentrations were related to the ventilation rate of the swine shed, the activity of the swine, and the temperature in the swine shed. Accordingly, the emission rates of VOCs from the swine shed were $1-2{\times}10^3{\mu}g(h\;kg-swine)^{-1}$.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.313-321
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• 2010

This study was carried out to investigate the emissions of the air pollutants from the automobile in Suwon city. To estimate emissions due to by automobile the data of express highway and the national road used an observation traffic volume, and the other roads used a method by Vehicle kilometer traveled(VKT). In the emissions due to by automobile from Suwon city, CO was highest 36,290.4 ton/year, NOx at 19,392.1 tons, HC 5,095.4 tons and PM 2,788.7 tons was highly order. SOx emissions in the whole Suwon city by fuel types was investigated with 178ton/year from the Diesel motorcar, 26.9 ton/year and 6.2 ton/year from the gasolines and LPG automobiles, respectively. VOC emissions from the automobile was investigated with 366.4 ton/year (29.22%) from Gwonseon-gu, 329.2 ton/year (26.25%) Yeongtong-gu, 319.9 ton/year (25.51%) Jangan-gu, 238.6 ton/year (19.03%) Paldal-gu.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.420-420
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• 2011

결정질 태양전지에서 고효율 달성을 위한 LBC(Local Back Contact) 구조의 중요성이 강조되고 있다. LBC 구조에서 후면 passivation 형성을 위한 SiNX layer를 PECVD로 형성 시, 실리콘 bulk 내로 H+ 원자가 침투하여 Boron과 결합하게 되면 Boron이 bulk 내에서 dopant로 작용을 하지 못하게 되어, 후면에서 p-층을 형성하고, 이는 VOC의 저하를 야기 시킨다. 본 연구에서는 LBC 구조에서 후면 passivation 시 bluk 내 B-H결합으로 인한 태양전지 특성 저하 문제를 해결하기 위해, SiNX를 증착하기 전에 얇은 산화막 barrier를 성장시켜 Bulk 내에 H+ 침투를 최소화 하였다. PECVD를 이용한 N2O 플라즈마 처리, HNO3 Wet Chemical Oxidation의 방법을 통해 substrate와 SiNX 사이에 얇은 oxide 층을 형성하였으며, 각각의 조건에 대해 lifetime 측정을 실시하였다. 그 결과 SiON/SiNx를 이용한 막의 lifetime이 $94.5{\mu}s$로 가장 우수하였고, Reference에 비해 25.4% 증가함을 확인할 수 있었다. 그러나 HNO3/SiNx에서는 30.6%, SiON에서는 84.3% 감소함을 확인하였다. Voc 측정 결과 또한 SiON/SiNx를 이용한 막이 670mV로 가장 우수함을 확인할 수 있었다. 본 연구를 통해 LBC구조에서 후면에 얇게 SiON/SiNx막을 형성함으로서 H+이온의 침투를 저지하여 후면 B-H결합을 막아 태양전지 특성 저하를 감소시키는 것을 확인할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.668-668
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• 2013

CIGS 박막태양전지는 다른 박막태양전지에 비해 높은 에너지 변환효율을 보이고 있으며, 광범위한 기술 응용분야를 가지고 있다. CIGS를 광흡수층으로 하는 태양전지의 구조는 5개의 단위박막(배면전극, 광흡수층, 버퍼층, 앞면 투명전극, 반사방지막)을 순차적으로 형성시켜 만든다. 단위박막별로 다양한 종류의 재료와 조성, 또한 제조방법에서는 갖가지 물리적, 화학적 박막 제조방법이 사용된다. 현재 광흡수층인 CIGS층의 경우 동시증발법과 스퍼터링법이 높은 효율을 보이고 있다. 본 연구에서는 CIGS층을 3-stage process를 적용한 동시증발법을 사용하였고, Fluxmeter와 기판후면 온도 모니터링을 이용하여 제조하였으며, 버퍼층은 moving 스퍼터링 법으로 ZnS를 증착하였고, 투명전극층은 PLD (Pulsed Laser Deposition)를 이용하여 제조하였다. 가장 높은 광변환효율을 보인 Al/ZnO/CdS/Mo/SLG박막시료는 유효면적 0.45 $cm^2$에 광변환효율 15.71%, Jsc: 33.64 mA/$cm^2$, Voc: 0.64 V, FF: 73.18%를 얻을 수 있었으며, CdS를 ZnS로 대체한 Al/ZnO/ZnS/Mo/SLG 박막시료는 유효면적 0.45 $cm^2$에 광변환효율 12.13%, Jsc: 33.22 mA/$cm^2$, Voc: 0.60 V, FF: 62.85%를 얻을 수 있었다.

• Asian Journal of Atmospheric Environment
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• v.2 no.2
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• pp.75-80
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• 2008

A new-type apparatus decomposing volatile organic compounds (VOCs) using a combination system of an electrical exothermic SiC honeycomb and a catalytic filter was developed. This linear combination system is very useful to the catalytic decomposition of VOCs, because the gas involving VOCs is well heated in the SiC honeycomb and then flows into the catalytic filter. In the proposed apparatus, the outlet gas temperatures of SiC honeycomb maintained at ca. $300^{\circ}C$ after 5 min from the starting of applying electric current, and sufficient for the catalytic degradation of VOC components, i.e. toluene, isopropanol, methyl ethyl ketone and ethyl acetate. The average decomposition rate of total VOCs exhausted from a printing factory was 85% using pt catalyst at SV=19,000 in this system.