• Title, Summary, Keyword: Generated aerosols

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Attachment Behavior of Fission Products to Solution Aerosol

  • Takamiya, Koichi;Tanaka, Toru;Nitta, Shinnosuke;Itosu, Satoshi;Sekimoto, Shun;Oki, Yuichi;Ohtsuki, Tsutomu
    • Journal of Radiation Protection and Research
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    • v.41 no.4
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    • pp.350-353
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    • 2016
  • Background: Various characteristics such as size distribution, chemical component and radio-activity have been analyzed for radioactive aerosols released from Fukushima Daiichi Nuclear Power Plant. Measured results for radioactive aerosols suggest that the potential transport medium for radioactive cesium was non-sea-salt sulfate. This result indicates that cesium isotopes would preferentially attach with sulfate compounds. In the present work the attachment behavior of fission products to aqueous solution aerosols of sodium salts has been studied using a generation system of solution aerosols and spontaneous fission source of $^{248}Cm$. Materials and Methods: Attachment ratios of fission products to the solution aerosols were compared among the aerosols generated by different solutions of sodium salt. Results and Discussion: A significant difference according as a solute of solution aerosols was found in the attachment behavior. Conclusion: The present results suggest the existence of chemical effects in the attachment behavior of fission products to solution aerosols.

Performace of a Cyclone and an impactor Using Monodisperse and Polydisperse Particles (단분산 입자와 다분산 입자를 이용한 싸이클론 및 임팩터의 성능평가)

  • Im Gyeong-Su;Lee Gyu-Won
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • pp.101-102
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    • 2001
  • Monodisperse aerosols containing spherical particles of known size, shape and density are the most widely used to calibrate particle-size measuring instruments and to determine the effects of particle size on the sampling device. However, these tests are time-consuming because monodisperse aerosols with different particle sizes are generated and tested in a series of experiments. Polydisperse aerosols may be used to determine the calibration or to simulate equipment under controlled laboratory condition. (omitted)

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Physico-Chemical Characterization of Black Carbon Emitted from Coal-fired Power Plant, Charcoal Kiln and Diesel Vehicle (석탄화력 발전소, 숯가마, 디젤차량에서 배출되는 Black Carbon의 물리화학적 특성화 연구)

  • Saixiyaletu, Saixiyaletu;Kim, Jin Young;Shim, Shang-Gyoo;Jin, Hyoun Cher;Kim, Jong Soo
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.2
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    • pp.152-162
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    • 2013
  • The physico-chemical characteristics and nanostructure of the aerosol samples from a coal-fired power plant, a charcoal kiln and diesel vehicles were investigated with focusing on black carbon (BC). Aerosols from the coal-fired power plant were mostly comprised of mineral ash spheres which are heterogeneously mixed. The main components of the aerosols from coal-fired power plant were calcium compounds, iron oxide, alumino-silicate without BC. The typical combustion-generated BC which shows the shape of bunch of grapes with 20~50 nm particles which were detected in aerosol particles from diesel vehicles. The nanostructure of each BC particle shows the shape of concentric circles which is comprised of closely-packed graphene layers. Aerosols from charcoal kiln were likely condensed organic carbon generated from the low-temperature combustion process.

The Occupational Exposure Limit for Fluid Aerosol Generated in Metalworking Operations: Limitations and Recommendations

  • Park, Dong-Uk
    • Safety and Health at Work
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    • v.3 no.1
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    • pp.1-10
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    • 2012
  • The aim of this review was to assess current knowledge related to the occupational exposure limit (OEL) for fluid aerosols including either mineral or chemical oil that are generated in metalworking operations, and to discuss whether their OEL can be appropriately used to prevent several health risks that may vary among metalworking fluid (MWF) types. The OEL (time-weighted average; 5 mg/$m^3$, short-term exposure limit ; 15 mg/$m^3$) has been applied to MWF aerosols without consideration of different fluid aerosol-size fractions. The OEL, is also based on the assumption that there are no significant differences in risk among fluid types, which may be contentious. Particularly, the health risks from exposure to water-soluble fluids may not have been sufficiently considered. Although adoption of The National Institute for Occupational Safety and Health's recommended exposure limit for MWF aerosol (0.5 mg/$m^3$ ) would be an effective step towards minimizing and evaluating the upper respiratory irritation that may be caused by neat or diluted MWF, this would fail to address the hazards (e.g., asthma and hypersensitivity pneumonitis) caused by microbial contaminants generated only by the use of water-soluble fluids. The absence of an OEL for the water-soluble fluids used in approximately 80-90 % of all applicants may result in limitations of the protection from health risks caused by exposure to those fluids.

Measurement of Nanoaerosol Size Distributions and PAHs Detection After Cooking (삼겹살과 고등어 조리시 발생하는 나노입자의 시간과 거리에 따른 크기분포와 PAH 검출)

  • Hahn, Jung Suk;Woo, Chang Gyu;Noh, Seung Ryul;Bae, Yong Jun;Sung, Hyangki;Choi, Man Soo
    • Particle and aerosol research
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    • v.7 no.3
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    • pp.71-77
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    • 2011
  • Pork belly meat and mackerel are popular meals in Korea. Although a lot of people enjoy cooking these food, there have been some reports that generated organic particles during cooking could be thereas on of lung cancer of nonsmoking housewives. In addition, some experiments show that carcinogens may be included in meat and fishes which we eat usually. For this reason, particle size and concentration in formation during cooking are necessary to figure out the relationship between particles and the diseases. Thus, we identify number concentrations and size distributions of generated nano aerosol in cooking with respect to time, hood operation, and distance between cooking and measurement locations. The maximum concentrations of nano aerosol(diameter sizes are between 10 to 700nm)are decreased after the cooking from $8{\times}10^6{\sharp}/cm^3$ to zeroth order in pork belly meat cooking, and from $3.5{\times}{\times}10^6{\sharp}/cm^3$ to zeroth order in mackerel cooking respectively. When it comes to hood operation during cooking, the detected concentrations of generated aerosols are decreased as in taking flow rate of the hood increases. In cooking pork belly meat, the reduced amount of concentration is about $3{\times}10^6{\sharp}/cm^3$ compared to no hood operation, when hood in taking flow rate is $610m^3/hr$ In mackerel cooking, reduced concentration is $6{\times}10^5{\sharp}/cm^3$ in the same condition. Also, Naphthalene and Fluorene, which are known as polycyclic aromatic hydrocarbons (PAHs), are detected in the generated aerosols during cooking.

Real -time Observation on Airborne Particles with Visual Impactor (입자의 실시간 관측이 가능한 임팩터의 설계 및 성능해석)

  • 육세진;안강호
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.1
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    • pp.67-76
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    • 2003
  • Recently consideration of health and interest on bio aerosols have been growing steadily. In this study, inertial impactor, which can be used to collect airborne particles and bio aerosols, was newly devised for real-time observation on the particles collected on impaction plate. and named Visual Impactor. Flow field and particle trajectory in the space between nozzle and impaction plate was analyzed numerically, and the collection effciencies were calculated. Calibration and performance evaluation of the Visual Impactor was conducted with polydisperse aerosols generated from 0.1% sodium chloride solution. Cut-off diameter from numerical simulation was in good agreement with that from experimental results. Because of particle bounce and particle deposition on nozzle tip due to short jet-to-plate distance, the collection efficiencies from numerical and experimental analyses were different slightly. Visual Impactor was used to collect airborne particles, and the features of collected particles could be seen in real-time. Airborne particles in different weather conditions (fine, cloudy, and rainy) were sampled and compared one another The features of collected airborne particles were dependent strongly upon relative humidity. In addition, with hours elapsing, shapes and colors of collected particles were changed by evaporation and surface tension, etc.

Ionic composition of aerosol particles under urban atmospheres of Seoul, Korea (서울시 대기중 입자상 오염물질의 조성에 관한 연구)

  • 한진석;김신도
    • Journal of Korean Society for Atmospheric Environment
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    • v.12 no.4
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    • pp.389-398
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    • 1996
  • In order to understand the relative importance of various pathways leading to the production and transformation of aerosols under different atmospheric conditions, the behavior of atmospheric aerosols have been investigated using a high volume tape sample in Seoul for a week period during August 1990. The concentrations of anion $(SO^{2-}_4, NO^-_3, CI^-)$ and cation $(Ca^{2+}, Na^+, NH^+_4)$ species of aerosol samples were analyzed to identify the ionic composition of aerosols and to estimate their relative contributions to aerosol formation. The concentrations of aerosol species were calculated by a multiple regression model. The results of our calculations indicate the existence of various chemical species such as $(NH_4)_2SO_4, Na_2SO_4, CaSO_4, NH_4NO_3, NaNO_3, Ca(NO_3)_2, NH_4Cl$, and NaCl salts. According to our calculations, the most dominant species of aerosol was $(NH_4)_2SO_4$ with the mean concentration of 23.3 $/mu g/m^3$ (66.9%). The proportion of different componts with aerosol (e.g., $NH_4NO_3$ and $NH_4Cl$) was strongly affected by temperature, relative humidity, and partial presure of gases.

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Design and Performance Evaluation of a Low Pressure Impactor for Sampling Submicron Aerosols (서브마이크론 입자 측정용 저압 임팩터의 설계 및 성능평가)

  • Ji, Jun-Ho;Cho, Myung-Hoon;Bae, Gwi-Nam;Hwang, Jung-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.3
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    • pp.349-358
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    • 2004
  • A low pressure impactor is an impaction device to separate airborne particles into aerodynamic size classes at low pressure condition. We designed a two-stage low-pressure impactor to classify submicron sized environmental aerosols. Performance evaluation was carried out for stages 1 and 2 by using an electrical method. Monodisperse liquid dioctyl sebacate (DOS) particles were generated using evaporation-condensation process followed by electrostatic classification using a DMA (differential mobility analyzer). The test particles were in the range of 0.08∼0.8$\mu\textrm{m}$. For the evaluation of the impactor we used two electrometers; one was connected to the impaction plate of the impactor and the other was to the Faraday cage used as a backup filter. The effect of polydispersity of test aerosols on the performance was investigated. The results showed that the experimental 50-% cutoff diameters at each impactor's operation pressure were 0.53 and 0.187$\mu\textrm{m}$ for stages 1 and stage 2, respectively. The effects of operation pressure on the cutoff diameter and the steepness of collection efficiency curves were also investigated.

Direct Analysis of Aerosol Particles by Atomic Emission and Mass Spectrometry

  • Kawaguchi, Hiroshi;Nomizu, Tsutomu;Tanaka, Tomokazu;Kaneco, Satoshi
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.411-418
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    • 1995
  • A method for the direct determination of elemental content in each of aerosol particles by inductively coupled plasma atomic emission (ICP-AES) or mass spectrometry (ICP-MS) is described. This method is based upon the introduction of diluted aerosol into an ICP and the measurement of either the flash emission intensities of an atomic spectral line or ion intensities. A pulse-height analyzer is used for the measurement of the distribution of the elemental content. In order to calibrate the measuring system, monodisperse aerosols are used. The potentials of the method are shown by demonstrating the copper emission signals from the aerosols generated at a small electric switch, a study of the relation between the decreasing rate of particle number density and particle size, and measurements of calcium contents in the individual biological cells.

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