• 한국환경보건학회지
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• 제36권3호
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• pp.171-181
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• 2010

Semivolatile aerosols exist as vapor and particles at the same time in room temperature and each phase has different intake and uptake mechanisms. This characteristic requires substantial consideration during exposure assessment of semivolatile aerosol. Some sampling methods for solid particles pose high possibility of evaporative loss during sampling. Therefore, when establishing sampling strategy for them, the factors affecting the phase distribution of semivolatile aerosol should be counted including semivolatile aerosol of interest and sampling methods used. Evaluation for phase distributions of semivolatile aerosols is also recommended. Metalworking fluids, pesticides, asphalt fumes, diesel exhaust, and environmental tobacco smoke are common health-related semivolatile aerosols in workplaces.

• Nuclear Engineering and Technology
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• 제29권4호
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• pp.269-279
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• 1997

The errors associated with incorrect sampling and transport of radioactive aerosol from radwaste thermal process off-gas are analyzed and the conditions of representative sampling and correct transport of radioactive aerosol for off-gas system evaluation are discussed. An estimation method of sampling errors for individual radionuclides is proposed and applied to simulated vitrification melter aerosols. Prediction methods for particle deposition in sample transport tube under laminar as well as turbulent flow conditions are also described by example calculations with simulated incinerator off-gas From the results of example calculations and plots, instrumental and operational conditions of radioactive aerosol sampling system with minimized errors and correction methods for nonideal sampling and transport are recommended.

• 한국입자에어로졸학회지
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• 제7권4호
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• pp.139-149
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• 2011

It is very important to measure atmospheric particles and evaluate the characteristics of them since aerosol can influence atmospheric environment, climate, and health. Satellite, aircraft, radio sonde are usually used to measure the vertical distribution of particle properties, temperature, humidity, and pressure. Although the method of using an aircraft is favorable to collect the horizontal distribution of the particles, but unadaptable to measure the vertical distribution of the particles. However, all-in-one balloon particle sampler system can collect particles depending on each altitude controling the balloon by winch. In this research, we performed the air sampling on the TEM grids using house made light weight impactor at the altitude of 300m and 900m. The collected particles were analyzed using TEM/EDS.

• 한국대기환경학회지
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• 제16권2호
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• pp.113-120
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• 2000

Effects of sea-salts on the properties of aerosol collected in a coastal region were studied by applying a gas-particle equilibrium model SCAPE to the measurement data from Korea Cheju Island in summer 1994. It was found that the observed higher ammonium concentrations in fine particles (PM2.5) than in TSP were caused by forced evaporation of ammonium in coarse fraction of aerosol by sea-salts and the degree of evaporation was quantified through an application of SCAPE. By subtracting the sea-salt fraction from the measured concentra-tions the changes of aerosol property were also studied. The concentrations of nitrate at both TSP and PM2.5 decreased when alkaline sea-salt fraction was removed from the measured data. Estimates of aerosol acidity increased for most samples with sea salt loadings, However in some cases with high mass fractions of sea-salt components the aerosol acidity of PM2.5 decreased slightly. This is though to be related with the formation of solid salt with the removal of sea-salts.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 춘계학술대회 논문집
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• pp.49-50
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• 2003

To know the properties of single aerosol particle is an essential prerequisite for understanding its chemical reactions in the atmosphere. Single particle analysis has the advantage of providing a great amount of information that cannot otherwise be obtained using methods of bulk analysis. And single particle analysis needs the short sampling time and the small sampling mass for analysis. This allows for a better determination of the temporal variation of the component concentrations in aerosol particles. (omitted)

• 한국대기환경학회지
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• 제30권1호
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• pp.1-17
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• 2014

Temporal variations of optical properties of urban aerosol in Seoul were estimated by the Optical Properties of Aerosols and Clouds (OPAC) model, based on hourly aerosol sampling data in Seoul during the year of 2010. These optical properties were then used to calculate direct radiative forcing during the study period. The optical properties and direct radiative forcing of aerosol were calculated separately for four chemical components such as water-soluble, insoluble, black carbon (BC), and sea-salt aerosols. Overall, the coefficients of absorption, scattering, and extinction, as well as aerosol optical depth (AOD) for water-soluble component predominated over three other aerosol components, except for the absorption coefficient of BC. In the urban environment (Seoul), the contribution of AOD (0.10~0.12) for the sum of OC and BC to total AODs ranged from 23% (spring) to 31% (winter). The diurnal variation of AOD for each component was high in the morning and low in the late afternoon during the most of seasons, but the high AODs at 14:00 and 15:00 LST in summer and fall, respectively. The direct negative radiative forcing of most chemical components (especially, $NO_3{^-}$ of water-soluble) was highest in January and lowest in September. Conversely, the positive radiative forcing of BC was highest in November and lowest in August due to the distribution pattern of BC concentration.

• 한국입자에어로졸학회지
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• 제13권4호
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• pp.165-172
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• 2017

For precise particle measurements in combustion environments, various dilution sampling methods were compared. Dilution equipments using dilution tunnels and hot/cold dilution with porous tube dilutors were most frequently used so far. The combination of porous tube dilutor and ejector diluter has relatively small footprint, and it results in lower particle losses compared to other methods. To determine the portion of condensable particulate matter, proper temperature control and flow control is required.

• 한국환경보건학회지
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• 제39권1호
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• pp.56-70
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• 2013

Objectives: This paper aims to investigate the seasonal deposition characteristics of water-soluble ion species by comparing the deposition amount of two samples taken according to different sampling methods of deposition for ambient aerosol such as gases and particulate matters. Methods: Deposition samples were collected using two deposition gauges in the downtown area of Iksan City over approximately two weeks of each season in 2004. The type of deposition gauges consisted of two different sampling methods known as dry gauge and a wet gauge. The dry gauge was empty and used a dry PE bottle with an inlet diameter of 9.6 cm. Before the beginning of each deposition sampling, a volume of 30-50 ml distilled ionized water was added to the wet gauge to wet the bottom during the sampling period. Deposition samples were measured twice per day and analyzed for inorganic water-soluble ion species using ion chromatography. Results: The daily deposition amounts of all measured ions in the dry gauge and the wet gauge showed a significant increase when precipitation occurred, having no difference of deposition amount between in the wet gauge and in the dry gauge. By excluding two samples from rainy days during the sampling period, the mean daily deposition of all ions in dry gauge and wet gauge were $6.58mg/m^2/day$ and $18.16mg/m^2/day$, respectively. The mean deposition amounts of each ion species were higher in the wet gauge than in the dry gauge because of the surface difference of the sampling gauge, especially for $NH_4{^+}$ and ${SO_4}^{2-}$. The mean deposition amounts of $NH_4{^+}$ and ${SO_4}^{2-}$ in the wet gauge were found to be about 15.4 times and 5.2 times higher than that in dry gauge, with a pronounced difference between spring and summer, while the remaining ion species were 1.1-2.0 times higher in the wet gauge than in the dry gauge. Dominant species in the dry gauge were $Ca^{2+}$ and $NO_3{^-}$, accounting for 36.4% and 18.1% of the total ion deposition, whereas those in the wet gauge were $NH_4{^+}$ and ${SO_4}^{2-}$, accounting for 32.5% and 25.0% of the total ion deposition, respectively. Conclusion: The seasonal differences in deposition amounts of water-soluble ion species in ambient aerosol depending on the two types of different sampling methods were identified. This suggests that the removal of ambient aerosol is strongly influenced by the weather conditions of each season as well as the condition of earth's surface, such as dry ground and water.

• 한국환경과학회지
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• 제4권1호
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• pp.53-62
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• 1995

대기중의 산성도($H^+$)를 측정하기 위하여 디누더 시스템(Annula Denuder System)을 이용하였다. 산성도 측정은 1990년 4월 부터 1001년 3월 까지 미국 시카고에서 81개 샘플을 12시간 동안 낮과 밤을 구분하여 측정하였다. 본 연구를 통하여 대기중의 산성도 측정은 디누더 시스템을 이용하면 보다 정확한 결과를 얻을 수 있을음 알 수 있었다. 여과지에 포집된 산성도($H^+$)를 추출해 낼때 사용하는 $HCIO_4$용액은 $10^{-5}N$의 농도를 사용하는 것이 $10^{-4}N$의 농도보다 더 정확한 결과를 얻을 수 있다. 보다 정확한 산성도를 측정하기 위해서는 에어로졸이 여과지에 포집되기 전에 가스 상태의 $NH_3$가 먼저 제거되어야 한다. 산성도는 계절에 따라 변하였고 여름에 가장 높은 농도를 나타냈다. $SO_4^{2+} 와 $NH_4^+$, 그리고 $SO_4^{2+}와 $H^+$의 상관관계는 높은 것으로 나타났다.

• 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.