• 한국입자에어로졸학회지
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• 제7권1호
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• pp.31-44
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• 2011

The hourly volatile organic compounds(VOCs) concentrations between 2005 and 2008 at Bulgwang photochemical assessment monitoring station were investigated to establish a method for quality assurance and quality control(QA/QC) procedure. Systematic error, erratic error, and random error, which was manifested by outlier and highly fluctuated data, were checked and removed. About 17.3% of the raw data were excluded according to the proposed QA/QC procedure. After QA/QC, relative standard deviation for representing 15 species concentrations decreased from 94.7-548.0% to 63.4-125.8%, implying the QA/QC procedure is proper. For further evaluation about the adequacy of QA/QC procedure, principal components analysis(PCA) was carried out. When the data after QA/QC procedure was used for PCA, the extracted principal components were different from the result from the raw data and could logically explain the major emission sources(gasoline vapor, vehicle exhaust, and solvent usage). The QA/QC procedure based on the concept of errors is inferred to proper to be applied on VOCs. However, an additional QA/QC step considering the relationship between species in the atmosphere needs to be further considered.

• 한국환경과학회지
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• 제29권5호
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• pp.495-506
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• 2020

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

• 한국입자에어로졸학회지
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• 제6권4호
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• pp.151-164
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• 2010

Inorganic ions and water are major components of ambient fine particles. Water content in fine particles is mainly determined by ambient meteorological conditions and the concentrations of hygroscopic species such as inorganic ions. Thus, to reduce fine particle mass concentration, it is important to accurately estimate the relationship between water content and the concentration of ions in fine particles. Water content in fine particles in Seoul are estimated by using a gas/particle equilibrium model to understand the characteristics of fine particle mass concentration. In addition, sensitivity of fine particle mass concentration to the changes of particulate ionic species (sulfate, nitrate, and ammonium) is estimated. It was found that water content in Seoul is mostly determined by the concentrations of the hygroscopic ionic species, especially, sulfate and ammonium, and ambient relative humidity.

• 한국입자에어로졸학회지
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• 제11권2호
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• pp.57-61
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• 2015

Atmospheric nano-particles along the altitude is one of the main factors causing severe weather phenomena. It is a challenge to find the precise particle size distribution. One useful instrument includes a scanning mobility particle sizer (SMPS). This measures the size distribution of submicron aerosols. The SMPS consists of a condensation particle counter (CPC), differential mobility analyzer (DMA), high voltage power supplier (HVPS), and neutralizer. Due to the many components, it is difficult to install a commercial SMPS into a tethered balloon package system (Eun, 2011). In this study, we customized a SMPS for the tethered balloon package system called Hy-SMPS. It is portable, compact in structure, and evaluated by TSI SMPS using mono and poly-dispersed particles.

• 보존과학회지
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• 제20권
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• pp.55-65
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• 2007

석탑 표면 흑화현상에 영향을 끼치는 탄소를 평가하기 위하여 석탑표면의 흑색층을 분석하였다. 원소분석기를 이용하여 총탄소량을 측정하였으며. 원소탄소와 유기탄소는 시료를 산처리하여 탄산염탄소를 제거한 후 OC/EC 탄소분석기를 이용하여 분석하였다. 이들 석탑 표면 흑색시료에서 검출된 원소탄소의 함량은 0.52%로 원소탄소 자체만으로 석탑 표면의 흑화현상을 설명하기에는 충분치 않은 양이나 중요한 역할을 하는 것으로 보인다. 석탑 흑색표면 내 원소탄소의 기원을 살펴보기 위해 석탑주변의 대기미세먼지 (PM-10)를 포집하여 성분을 검토하였다. 대기미세먼지 중에서 가장 높은 비율을 차지하고 있는 것은 이온성분으로 38.4%였으며 토양지각성분이 16.6%. 탄소성분이 38.4%로 측정되었다. 대기의 높은 원소탄소함량(13 wt.%)은 석탑 흑색표면에서 검출된 원소 탄소의 기원으로 판단된다. 대기중의 토양성분 또한 석탑 흑색표면이 함유하고 있는 규산염광물의 기원으로 추정되며, 석탑표면에 축적되어 표면을 어둡게 하는 역할을 한다.

• 한국대기환경학회지
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• 제31권4호
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• pp.319-329
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• 2015

The characteristics of aerosol light extinction were investigated by comparing measured and calculated extinction coefficient to understand the contribution of air pollutants on visibility impairment for data during 4 months (Jan~ April), 2014. The integrated nephelometer and aethalometer system were installed to measure the scattering and absorption coefficients of aerosol as well as BAM 1020, MARGA, semi-continuous OCEC analyzer, and online-XRF to calculate the extinction coefficient. The IMPROVE_2005 equation was used to determine the contributions of different chemical components on visibility impairment in $PM_{2.5}$ and $PM_{10}$ due to highest correlation with measured data. Sulfate, nitrate, and organic mass by carbon (OMC) of fine aerosol were the major contributors affecting on visibility impairment. Total contributions to light extinction were calculated as $631.0Mm^{-1}$ for the worst-case and $64.4Mm^{-1}$ for the best-case. The concentrations of aerosol component for the worst-case were 38.4 times and 45.5 times larger than those of the best-case for $(NH_4)_2SO_4$ and $NH_4NO_3$, respectively. At lower visibility condition, in which extinction coefficient was higher than $400Mm^{-1}$, extinction coefficient varied according to the relative humidity variation regardless of $PM_{2.5}$.

• 한국지구과학회지
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• 제33권3호
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• pp.259-268
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• 2012

해양에서 발달하는 강수시스템의 연직풍에 따라 변동하는 해양성 에어러솔의 입경별 특성을 알아보기 위하여 마라도에서 남서쪽으로 419 km 지점에 위치한 이어도 해양종합과학기지에서 2009년 6월 8일부터 22일까지 에어러솔수 농도와 연직풍 관측을 실시하였다. 에어러솔 수 농도와 연직풍은 레이저입자계수기와 초음파 3차원 풍향 풍속계를 이용하였으며, 지상일기도, NCEP/NCAR 재분석자료, 라디오존데 자료를 이용하여 종관상태를 분석하였다. 그 결과, 전체적으로 1.0 ${\mu}m$ 이상의 크기의 에어러솔 수 농도 분포가 강수 중에 크게 변동하였으며, 하강류에서 상승류로 연직풍이 변함에 따라 크게 증가하였다. 강수 중에는 큰 입자(1.0 ${\mu}m$ 이상)의 에어러솔 수 농도가 약 5배 증가하였고, 이때 상승류가 약 0.4 $ms^{-1}$로 나타났다. 또한 축적모드(1.0 ${\mu}m$ 미만)와 큰 입자(1.0 ${\mu}m$ 이상)의 에어러솔 수 농도는 강수 중과 비교하여 약 45%와 92%가 제거되었다. 이는 독립된 해양지역에서의 큰 입자(1.0 ${\mu}m$ 이상) 에어러솔 수 농도 증가는 수평풍 보다는 상승류에 의해 크게 영향을 받고, 강수에 의한 세정효과도 나타났다. 따라서 해양경계층 내 에어러솔의 생성 및 발달 메커니즘에 상승류의 영향이 크게 기인함을 알 수 있었다.

• 한국입자에어로졸학회지
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• 제11권1호
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• pp.9-19
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• 2015

This study investigated the effects of ball mill operation condition on the morphology of raw powders in the dry-type milling process using three types of ball mills traditional ball mill, stirred ball mill and planetary ball mill. Furthermore, since spherical powders offer the best combination of high hardness and high density, the optimum milling condition to produce sphere-shaped powders was studied. The applied rotation speed ranged from 200rpm (low rotation speed) to 700rpm (high rotation speed). The used ball size ranged from 1mm to 5mm. The metal powder morphology was studied using SEM, XRD and PSA. The aimed spherical powders could be obtained under the optimum experimental conditions: traditional ball mill(200rpm, 1mm ball), planetary ball mill (500rpm, 1mm ball) and also planetary ball mill (700rpm, 1 and 3 mm ball). The results show to the development of new material using spherical type copper powder/CNT composites for air-craft and automotive applications.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1642-1647
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• 2009

황사기간 중 천안시 대기 입자의 특성 변화를 파악하기 위해, Cascade Impactor를 장착한 High Volume Air Sampler를 이용하여 대기 시료를 채취하여, 대기 입자의 입경별 질량농도 및 이온, 금속 성분의 농도를 황사기간과 비황사기간에 비교 측정하였다. 황사기간 중 일평균 TSP, PM10, PM2.5 평균 농도가 각각 214.9, 160.3, 95.9${\mu}\;g/m^3$으로, 비황사기간에 비해 각각 평균 3.08, 2.58, 1.95배 증가하였으며, 최대 농도는 TSP, PM10, PM2.5가 각각 850.1, 534.4, 233.3${\mu}\;g/m^3$으로, 비황사기간에 비해 각각 12.19, 8.60, 4.76배까지 증가하였다. 황사기간 중 농도의 증가는 미세입자보다는 조대입자에서 현저하였으며, 미세입자와 조대입자 모두 수용성 이온성분의 증가는 미미한 반면, 토양의 주요 구성 성분인 Fe, Al, Ti의 증가가 뚜렷이 관측되어, 토양구성 금속성분이 황사기간 중 입자 농도 증가의 주요원인 물질임을 확인할 수 있었다.

• 한국대기환경학회지
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• 제12권2호
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• pp.159-165
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• 1996

In order to study the scavenging mechanism as a final goal, the characteristics of chemical components in the rain water were examined as a function of the amount of rainfall. The rain drops were collected sequentially with a rainfall interval amount of each 0.1 .sim. 0.5 mm from the beginning of rain. Rain water was separated into the soluble and insoluble components and the concentrations of 15 elements in both components were determined by the PIXE analysis. The elemental cencentrations decreased quickly till about 0.3 .sim. 0.5 mm of rainfall was obtained and then decreased gradually afterward. Fe, Ti, and Si in the aerosol particles caught in rain water were in high insoluble state. In contrast, almost whole of S and Cl were dissolved in rain water.