• 한국대기환경학회지
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• 제25권2호
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• pp.141-153
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• 2009

$PM_{2.5}$ samples were collected from December 2005 through November 2007 in two cities including Chuncheon and Seoul in order to investigate the characteristics of carbonaceous aerosol. The average $PM_{2.5}$ concentration in Seoul ($43.2{\mu}g/m^3$) was approximately 1.2 times higher than that measured in Chuncheon ($36.1{\mu}g/m^3$), however there was no statistical difference on $PM_{2.5}$ concentration between those two cities. Backward trajectories were passing through Seoul area before arriving Chuncheon for about half of the samples, and $PM_{2.5}$ largely increased in Chuncheon when back-trajectories originated from Seoul area. Total carbon (TC) was calculated as sum of OC and EC, contributing 20.5% and 29.2% to total $PM_{2.5}$ mass in Chuncheon and Seoul, respectively. The average ratio of secondary organic carbon (SOC) to total OC was 40% at both sites, and the highest SOC concentration was observed in summer probably due to enhanced volatilization of organic species and active photochemical reaction. J value was calculated to determine if acidic condition affected the increase of secondary organic carbon. In both Chuncheon and Seoul SOC/OC ratios were fairly enhanced when J<100% of acidic condition.

• 한국대기환경학회지
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• 제14권6호
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• pp.621-630
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• 1998

The concentrations of organic carbon (OC) and elemental carbon (EC) in fine aerosols were determined from the samples collected at the two background sites of Kosan in Cheju Island and Kangwha. Samplings were carried out during the spring and winter of 1996 and the fall and winter of 1997. PM25 particles were collected on the prefired quartz filters for 24 hours and analyzed by the selective thermal oxidation method. The concentrations of OC at the sites were higher than those commonly observed from clean areas around the world, but those of EC at both sites were lower than, or comparable to, other clean areas in the world. Both the OC and EC levels at Kangwha were higher than those at Kosan. According to backward trajectory analysis, most air pollutants collected at the two sites were from China. It was found that the OC and EC concentrations in air masses from southern China were higher than those from northern China.

• 한국대기환경학회지
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• 제33권3호
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• pp.205-216
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• 2017

Carbonaceous aerosols such as the equivalent black carbon (eBC), the elemental carbon (EC) and the organic carbon (OC) were monitored at the Seoul Olympic Park site ($37.521^{\circ}N$, $127.124^{\circ}E$) during the KORUS-AQ 2016 campaign using a Multi Angle Absorption Photometer (MAAP) and an OCEC Analyzer. Averaged mass concentrations of eBC, EC and OC were presented as $2.46{\pm}1.52{\mu}g/m^3$, $1.01{\pm}0.60{\mu}g/m^3$ and $4.85{\pm}2.60{\mu}g/m^3$, respectively. OC/EC ratio and mass absorption cross-section (MAC) of light absorbing aerosols were calculated as 2.32 and $14.8m^2/g$, respectively. Diesel OC concentrations were estimated from a source profile of diesel vehicles as well. eBC mass concentrations measured from May $26^{th}$ to May $27^{th}$, 2016 showed 40% higher than averaged eBC mass concentrations during campaign period. $PM_{2.5}$ concentrations measured in this period were also higher than average $PM_{2.5}$ concentrations. High eBC concentrations were observed from May $29^{th}$ to May $31^{st}$, 2016 and from June $9^{th}$ to June $11^{th}$, 2016, possibly due to morning rush hour and the effect of temperature inversion at night. Diurnal variations of eBC, EC and Diesel OC showed a typical pattern of metropolitan area. In the weekend, however, diurnal variations of eBC, EC and Diesel OC mass concentrations were different from those measured in the weekday. It is expected that this study can help to understand the relationship between carbonaceous aerosols in a metropolitan area.

• 한국대기환경학회지
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• 제32권3호
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• pp.272-279
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• 2016

Understanding sources and contributions of $PM_{2.5}$ mass and particulate PAHs from traffic-related pollution can provide valuable information for alleviating air contamination from car emissions in urban areas. Two sampling sites at the Gwangju Institute of Science and Technology (GIST, $35.228^{\circ}N$, $126.843^{\circ}E$) and National institute of environmental research NamBu Supersite (NNBS, $35.226^{\circ}N$, $126.848^{\circ}E$) were selected for comprehensive road-oriented-PM investigations. Continuous measurements from optical particle sizer (OPS) and optical particle counter (OPC) with 24 hr integrated filter based samplers for organic carbon, water soluble organic carbon, and Poly Aromatic Hydrocarbons (PAHs) were conducted during Nov. 3 through 22 in 2014. As a result, $PM_{2.5}$ mass concentrations using OPC and OPS in NNBS presented about twice higher than in GIST due to road dust impacts based on wind direction analysis. In addition, ratios of elemental carbon (EC) to organic carbon (OC) and water insoluble organic carbon (WIOC) to organic carbon (OC) supported an additional evidence of the primary pollutant contributions oriented from road dust. PAHs related to 5 rings such as benzo(e&a)pyrene indicates higher associations.

• 한국대기환경학회지
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• 제32권1호
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• pp.21-31
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• 2016

Organic carbon (OC) and elemental carbon (EC) in $PM_{2.5}$ were measured with Sunset OC/EC Field Analyzer at Taehwa Research Forest (TRF) near Seoul metropolitan area from May 2013 to April 2014. During the study period, the mean concentrations of OC and EC were $5.0{\pm}3.2{\mu}gC/m^3$ and $1.7{\pm}1.0{\mu}gC/m^3$, respectively. They showed clear seasonality reaching their maximum in winter ($6.5{\mu}gC/m^3$ and $1.9{\mu}gC/m^3$) and minimum in wet summer ($2.5{\mu}gC/m^3$ and $1.4{\mu}gC/m^3$). While OC showed greater seasonal variation, the diurnal variation was more noticeable for EC through all seasons with a clear maximum in the morning, which reveals the influence of vehicle emissions. In contrast, OC exhibited a broad second peak in the afternoon during May~June, when biological activities were the highest. Using the morning peaks of EC and OC, primary OC/EC ratio was assessed, which was assumed to be anthropogenic origin. It was the greatest in winter followed by spring and the lowest in wet summer. The seasonal difference in primary OC/EC ratio implies the influence of non-local sources of OC at the Mt. Taehwa.

• 한국진공학회지
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• 제17권2호
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• pp.117-121
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• 2008

탄소계열의 SiOC 박막은 화학적 증착방법으로 bistrimethylsilylmethane와 산소의 혼합개스를 사용하여 증착하였다. SiOC 박막의 화학적인 특성은 FTIR 분석을 이용하였으며, I-V 측정법을 이용하여 비교하였다. $950\sim1200\;cm^{-1}$ 영역에서 생기는 결합들은 Si-C 결합, Si-O-C 결합과 Si-O 결합으로 이루어졌으며, SiOC 박막의 누설전류는 탄소함량이 증가함에 따라서 증가하였다. 그리고 누설전류는 Si-O-C 결합의 함량과 유사한 경향성을 나타냈다. FTIR 분석에서 디컨벌류션한 데이터는 SiOC 박막이 3가지 특성이 있는 것을 확인할 수 있었으며, 접촉각은 이러한 3가지 유형에 대한 차이점을 보여주었다.

• 한국대기환경학회지
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• 제34권3호
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• pp.447-456
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• 2018

Elemental carbon (EC) and organic carbon (OC) thermal/optical methods for the analysis of ambient particulate matter were used to analyze twenty-two $PM_{2.5}$ samples along collected from May 28 to June 20 of 2016 at the Anmyeon measurement site ($36.32^{\circ}N$; $126.19^{\circ}E$). The three laboratory OCEC protocols, which are the National Institute of Occupational Safety and Health (NIOSH5040), the Interagency Monitoring of Protected Visual Environments_A(IMPROVE_A), and European Supersites for Atmospheric Aerosol Research2 (EUSAAR2), were utilized for the aerosol characterization experiment as in intercomparisons between three protocols. There are excellent agreement for total carbon (i.e. sum of EC and OC), but statistically significant differences were observed in the split between the measured EC and OC. IMPROVE_A EC values were always larger than both NIOSH5040 and EUSAAR2 protocols. These methods exhibited significantly different temperature-distributions based on thermogram analysis, which is normalized to total carbon. In this study, a protocol for carbonaceous analysis is suggested for the Korean Peninsula.

• 한국입자에어로졸학회지
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• 제9권2호
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• pp.89-102
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• 2013

24-hr $PM_{2.5}$ samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species($Na^+$, $NH^{4+}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of $PM_{2.5}$ and its chemical components. An Asian dust event was also observed, during which $PM_{2.5}$ concentration was 64.5 ${\mu}g/m^2$. Crustal materials during Asian dust event contributed 26.6% to the $PM_{2.5}$, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, ${NO_3}^-$, ${SO_4}^{2-}$, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, ${NO_3}^-$ and ${SO_4}^{2-}$. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.

• The Plant Pathology Journal
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• 제26권2호
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• pp.198-202
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• 2010

A study was conducted to find out the relationship of physico-chemical properties (viz. organic carbon(OC), pH, electrical conductivity, nitrogen, phosphorus and potassium content) of ginger growing soil with incidence percentage of rhizome rot and wilt disease complex of ginger. Organic carbon content and pH of the ginger soil contributed significantly (93%) in the prediction of ginger rhizome rot and wilt disease complex incidence with negative correlation. Soil having weak acidic reaction with OC percent greater than 2.25 was observed to have the lower average incidence of the disease.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2010년도 춘계학술대회 논문집
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• pp.219-220
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• 2010