• 한국입자에어로졸학회지
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• 제14권1호
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• pp.17-24
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• 2018

Since the motion of the charged particle strongly depends on its charge characteristics, information on charge distributions of target particles is one of the important variables in aerosol research. In this study, charged distribution of atomized NaCl particles were measured using a Gerdien type ion counter. Two kinds of particle charging conditions were used in this study. First, atomized NaCl particles were passed through an aerosol neutralizer to have a Boltzmann charge distribution, and then its charge distribution was measured. In this case, the portion of uncharged particles was compared with the portion obtained from the Boltzmann charge distribution for verifying the suggested experimental method. Second, same experiment was conducted without the aerosol neutralizer to measure the charge distribution of atomized and un-neutralized NaCl particles. In the conclusion, the portion of uncharged, negatively charged and positively charged particles were 19%, 62% and 20%, respectively, for neutralized particles. The atomized particles, which was generated without the aerosol neutralizer, also had almost a zero charge state, but the standard deviation in charge distribution was larger than that of neutralized particles. The test method proposed in this study is expected to be used in various aerosol research fields because it can obtain simple information on the particle charge characteristics more easily and quickly than the existing test methods.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1349-1353
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• 2008

충청남도, 천안시 대기 에어로졸의 입경별 농도 및 이온성분 특성을 분석하고자, 2006년 3월부터 2007년 4월까지 천안시 상명대학교에서 Cascade Impactor를 장착한 High Volume Air Sampler를 이용하여 대기 시료를 채취 분석하였다. 입경별 에어로졸의 일평균농도는 TSP, PM10, PM2.5, PM1이 각각 61.7, 55.2, 43.7, $33.2{\mu}g/m^3$였으며, 직경이 $1{\sim}3{\mu}m$인 영역을 경계로 조대영역과 미세영역으로 나누어지는 전형적인 도심지 특성을 나타냈다. 이 중 미세영역입자인 PM2.5이 전체 에어로졸의 70.8%를 차지하였다. 이들 에어로졸 입자의 성분 분석 결과 양이온은 ${NH_{4}}^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$이, 음이온은 ${SO_{4}}^{2-}$, ${NO_{3}}^-$, $Cl^-$가 주요 성분이었으며, 이들 수용성 이온이 차지하는 비율은 조대입자에서 37.4%, 미세입자에서 46.2%였다.

• 한국입자에어로졸학회지
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• 제9권1호
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• pp.7-21
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• 2013

Twelve-hour size-resolved atmospheric aerosols were measured to determine size distributions of water-soluble organic carbon(WSOC) during daytime and nighttime, and to investigate sources and formation pathways of WSOC in individual particle size classes. Mass, WSOC, ${NO_3}^-$, $K^+$, and $Cl^-$ at day and night showed mostly bimodal size distributions, peaking at the size range of $0.32-0.55{\mu}m$(condensation mode) and $3.1-6.2{\mu}m$(coarse mode), respectively, with a predominant condensation mode and a minor coarse mode. While ${NH_4}^+$ and ${SO_4}^{2-}$ showed unimodal size distributions which peaked between 0.32 and $0.55{\mu}m$. WSOC was enriched into nuclei mode particles(< $0.1{\mu}m$) based on the WSOC-to-mass and WSOC-to-water soluble species ratios. The sources and formation mechanisms of WSOC were inferred in reference to the size distribution characteristics of inorganic species(${SO_4}^{2-}$, ${NO_3}^-$, $K^+$, $Ca^{2+}$, $Na^+$, and $Cl^-$) and carbon monoxide. Nuclei mode WSOC was likely associated with primary combustion sources during daytime and nighttime. Among significant sources contributing to the condensation mode WSOC were homogeneous gas-phase oxidation of VOCs, primary combustion emissions, and fresh(or slightly aged) biomass burning aerosols. The droplet mode WSOC could be attributed to aqueous oxidation of VOCs in clouds, cloud-processed biomass burning aerosols, and small contributions from primary combustion sources. From the correlations between WSOC and soil-related particles, and between WSOC and sea-salt particles, it is suggested that the coarse mode WSOC during daytime is likely to condense on the soil-related particles($K^+$ and $Ca^{2+}$), while the WSOC in the coarse fraction during nighttime is likely associated with the sea-salt particles($Na^+$).

• 설비공학논문집
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• 제6권3호
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• pp.237-246
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• 1994

Experimental data are reported for charging and collection of NaCl aerosols in the 0.03- to $0.2{\mu}m$-geometric-mean-diameter range in 2-stage parallel-plate electrostatic precipitators. The NaCl aerosols are generated with geometric standard deviation of about 1.74 and particle generation rate of about 10^9 particles/see by the constant output atomizer and injected into the air flow in the clean wind-tunnel. The 2-stage parallel-plate electrostatic precipitator installed in the test section of the wind-tunnel is operated with a positive corona discharge. The NaCl aerosols in the channel flow are sampled and transported to the aerosol particle number concentration measurement system by using the isoaxial sampling and transport system constructed based on the Okazaki and Willeke design. The aerosol particle number concentration measurement system measures the size distribution of submicrometer aerosols by an electrical mobility detection technique. It is confirmed from comparing the measured collection efficiencies in this study and the predicted ones by our previous theoretical analysis that the predicted collection efficiencies agree well with the experimental ones. It is also found from the comparison that below about $0.02{\mu}m$ all particles are not charged and the uncharged particles are not collected, and consequently 2-stage parallel-plate electrostatic precipitators are not suitable for that particle size range.

• 한국입자에어로졸학회지
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• 제12권3호
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• pp.95-102
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• 2016

본 연구에서는 호흡용 보호구 필터의 나노물질에 대한 여과특성을 측정하기 위해서 소금(NaCl)과 은나노입자(Ag)를 대상으로 입경별 집진효율을 평가하였다. 호흡용 보호구 필터는 특급 방진마스크와 1급 방진마스크의 두 가지 안면부 여과식 방진마스크인 사용하였고, 마스크의 배기밸브 부분을 제외한 필터 여재 부분을 직경 47 mm로 잘라내어 필터홀더에 부착하여 입경별 입자제거효율을 시험하였다. 시험입자는 일반적으로 시험 입자로 사용되는 소금입자는 분무형 입자발생장치를 사용하여 발생하였고 중화기를 통과시켜 입자의 하전특성을 볼츠만 분포로 만들어 공급하였다. 은나노입자의 경우, 기화-응축 방법을 이용한 금속나노입자 생성방법인 ISO10801 방법을 사용하였다. 작업장의 은나노입자의 고농도 노출을 모사하기 위해, 중화기를 통과하지 않은 나노입자를 시험입자로 사용하였다. 은나노입자의 경우 소금입자로 만들기 어려운 20nm 이하의 입자를 안정적으로 효과적으로 만들어 시험에 적용하였고, 나노 크기에서도 매우 안정적인 데이터를 확보할 수 있었다. 1급 마스크 필터와 특급 마스크 필터에 대한 소금입자의 평가에서, 입경별 최소효율이 30~50nm 사이에서 나타나는 특성은 기존 연구와 비슷한 결과를 얻었다. 반면, 은나노입자의 경우 1급 마스크 필터와 특급 마스크 필터 모두에서 비슷한 크기의 소금 입자와 비교할 때 높은 효율을 나타냈다. 이것은 소금 입자의 경우 중화기를 통과시켜 시험입자로 사 용한 반면, 은나노입자의 경우 중화기를 통과시키지 않았기 때문이다. 본 연구에서는 작업장에서 은나노 입자가 고농도로 노출될 경우를 모사하여, 기화-응축에 의한 방법의 은나노입자 발생장치를 사용하였는데, 이 때 상대적으로 높게 대전된 입자들이 많이 만들어진다(Jung et al., 2006). 이로 인해, 정전필터인 마스크 필터의 포집 효과가 상대적으로 크기 때문에, 입경별 효율이 높아진 것으로 생각된다. 본 연구에서 평가한 1급 및 특급 방진마스크 여재의 최소 포집효율은 유럽 EN 149 기준인 95 LPM 유량 기준을 만족하는 것으로 나타났지만, 이것은 여재에 대한 평가 결과로, 실제 마스크에 대해서는 여재의 구조적인 불균일성이나 마스크를 착용하는 과정에서 밀착이 되지 않아 누출될 가능성은 마스크 사용에 고려되어야 한다. 불시에 발생할 수 있는 작업장 내 안전사고의 예방을 위하여 적절한 보호구의 선택과 올바른 착용 및 유지관리가 필요할 것으로 생각된다.

• 한국세라믹학회지
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• 제48권5호
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• pp.439-446
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• 2011

Yttria stabilized zirconia (YSZ) coating was formed on AA1050 Al alloys by aerosol deposition (AD), and its electrochemical corrosion properties were investigated in 3.5 wt% NaCl and 0.5M $H_2SO_4$ solutions. The crack-free, dense, and ~5 ${\mu}m$ thick YSZ coating was successfully obtained by AD. The as-deposited coating was composed of cubic-YSZ nanocrystallites of ~10 nm size. The potentiodynamic test indicated that the YSZ coated Al alloy had much lower corrosion current densities (2 nA/$cm^2$) by comparison to uncoated sample and exhibited a passive behavior in anodic branch. Particularly, a pitting breakdown potential could not be identified in $H_2SO_4$. EIS tests revealed that the impedance of YSZ coated sample was ${\sim}10^6{\Omega}cm^2$ in NaCl and ${\sim}10^7{\Omega}cm^2$ in $H_2SO_4$, which was about 3 or 4 orders of magnitude higher than that of uncoated sample. Consequently, the corrosion resistance of Al alloy had been significantly enhanced by the YSZ coating.

• 대한기계학회논문집B
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• 제28권3호
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• pp.315-323
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• 2004

An electrical cascade impactor is a multi-stage impaction device to separate airborne particles into aerodynamic size classes using particle charging and electrical detection techniques. A Faraday cage and an aerosol charger, which are basic components of the electrical cascade impactor, were designed and evaluated in this study. The low-level current response of the Faraday cage was investigated with changing particle size and air flow rate by using sodium chloride (NaCl) particles. The response of the prototype Faraday cage was very similar to that of a commercial aerosol electrometer (TSI model 3068) within ${\pm}$5% for singly-charged particles. The response linearity of the prototype Faraday cage could be extended up to flow rate of 30 L/min. For the performance evaluation of the aerosol charger the monodisperse liquid dioctyl sebacate (DOS) particles, with diameters of 0.1∼0.8$\mu\textrm{m}$, were generated using spraying from an atomizer followed by evaporation-condensation process. Typical performance parameters of the aerosol charger such as P$.$n, wall loss, and elementary charges per particle were evaluated. The performance of the prototype aerosol charger was found to be close to that of the aerosol charger used in an electrical low pressure impactor (ELPI, Dekati).

• 한국입자에어로졸학회지
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• 제11권2호
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• pp.29-36
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• 2015

The purpose of this research is to find out the collection property of nanoparticle in diffusion filter to know particle size dispersion of nanomaterial using inertial force and principle of Brownian diffusion motion. We used inertial filters which are two different type and diffusion filters made by various kinds of Wiremesh and the different pieces of filter to compare with particle size distribution using NaCl particles. Finally, We made a conclusion as follows : (1) the bigger available charging volume is and the larger specific surface area of inertial filter is, the better collection efficiency is. (2) The higher wire-mesh number of filter is, the more collection efficiency of small particle is increasing because the wire of the higher Wiremesh number filter is thinner and denser. (3) The more pieces of wire-mesh filter, the more collection efficiency is increasing because it makes the residence time longer.

• 분석과학
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• 제23권4호
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• pp.371-382
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• 2010

제주도 고산지역에서 TSP (total suspended particulate), PM2.5 (particulate matter, below $2.5\;{\mu}m$ particle size) 대기에어로졸을 채취, 분석하여 에어로졸의 조성과 오염 특성을 조사하였다. 고산지역 대기에어로졸에서 nss(non-sea salt)-$SO_4^{2-}$과 $NH_4^+$은 다른 국내 청정지역 및 도시지역에 비해 높은 조성비를보이고 $NO_3^-$는 상대적으로 낮은 조성비를 나타내었다. 에어로졸 성분의 입경별 분포를 비교해 본 결과, 인위적 기원의 nss-$SO_4^{2-}$, $NO3_^-$, $NH_4^+$ 성분들은 대체적으로 미세입자에, 토양기원의 nss-$Ca^{2+}$과 해염기원의 $Na^+$, $Cl^-$, $Mg^{2+}$은 상대적으로 조대입자에 많이 분포하고 있는 것으로 확인되었다. 계절별로는 봄철에 nss-$Ca^{2+}$, Al, Fe, Ca, $NO_3^-$ 성분의 농도가 크게 상승하고, nss-$SO_4^{2-}$은 여름과 봄철에 높은 농도를 나타내었다. 인자분석 결과, 에어로졸은 대체적으로 인위적 발생원의 영향을 많이 받고, 다음으로 해양 및 토양 영향을 많이 받았다. 또한 역궤적 분석법으로 에어로졸 성분의 유입경로를 조사해 본 결과, nss-$SO_4^{2-}$, $NO_3^-$, Pb, nss-$Ca^{2+}$ 성분들은 대체적으로 기류가 중국대륙으로부터 제주지역으로 이동할 때 훨씬 더 높은 농도를 나타낸 반면, 북태평양에서 제주지역으로 이동할 때 상대적으로 낮은 농도를 나타내었다.

• 한국환경과학회지
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• 제29권1호
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• pp.79-93
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• 2020

To determine the size distributions of water-soluble inorganic ionic species (WSIS) in roadside aerosols, sampling experiments were carried out in the urban roadside area of Jeju City on August 2018 and January 2019 by using the eight-stage cascade impactor sampler. The mass of roadside aerosols were partitioned at 57% in fine fraction, 36-37% in coarse fraction, and 6-7% in giant fraction, regardless of summer and winter. The mass concentrations of WSIS except for Na+ and SO42- in roadside aerosols were higher in winter than in summer. The size distributions of Na⁺, Mg²⁺, Ca²⁺ and Cl^- were characterized by bimodal types with coarse particle mode peaking around 3.3-4.7 ㎛ and 5.8-9.0 ㎛. The size distributions of NO₃^- and K⁺ shifted from a single fine mode peaking around 0.7-1.1 ㎛ in winter to bimodal and/or trimodal types with peaks around coarse mode in summer. SO₄^2- and NH₄⁺ showed a single fine mode peaking around 0.7-1.1 ㎛. The MMAD of roadside aerosols was lower than that of Na⁺, Mg²⁺, Ca²⁺ and Cl-. Based on the marine enrichment factors and the ratio values of WSIS and the corresponding value for sea water, the composition of roadside aerosols in Jeju City may be practically affected by terrestrial sources rather than marine source.