• 제목/요약/키워드: Atmospheric composition

검색결과 411건 처리시간 0.031초

Low-Z Electron Probe X-ray Microanalysis 분석법을 이용한 해안인근 지역의 대기입자 분석 (Characterization of Individual Atmospheric Particles, Collected in Susan, Korea, Using Low-Z Electron Probe X-ray Microanalysis)

  • 김혜경;노철언
    • 한국대기환경학회지
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    • 제19권5호
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    • pp.503-513
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    • 2003
  • A single particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA) was applied to characterize atmospheric particles collected in Busan, Korea, over a daytime period in Dec. 2001. The ability to quantitatively analyze the low-Z elements, such as C, N, and 0, in microscopic volume enables the low-Z EPMA to specify the chemical composition of individual atmospheric particle. Various types of atmospheric particles such as organics, carbon-rich, aluminosilicates, silicon oxide, calcium carbonate, iron oxide, sodium chloride, sodium nitrate, ammonium sulfate, and titanium oxide were identified. In the sample collected in Busan, sodium nitrate particles produced as a result of the reaction between sea salt and nitrogen oxides in the atmosphere were most abundantly encountered both in the coarse and fine fractions. On the contrary, original sea salt particles were rarely observed. The fact that most of the carbonaceous particles were distributed in the fine fraction implies that their origin is anthropogenic.

대기수은의 환경지화학: 배경농도측정 및 대기-지표면간의 교환작용 (Environmental Geochemistry of Atmospheric Mercury: Its Backgriound Concentrations and Exchange Across the Air-Surface Interface)

  • 김기현
    • 한국대기환경학회지
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    • 제12권2호
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    • pp.189-198
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    • 1996
  • Mercury (Hg) is ubiquitous throughout the earth's atmosphere. The uniqueness of its atmospheric geochemistry is well-known with the high environmental mobility and relatively long atmospheric residence time (c.a., 1 year) associated with its high chemical stability. Despite a growing recognition of the environmental significance of its global cycling, the prexisting Korean database for atmospheric Hg is extremely rare and confined to a number of concentration measurements conducted under relatively polluted urban atmospheric environments. To help activate the research on this suvject, an in-depth analysis on the current development in the measurements of atmospheric mercury and the associated fluxes has been made using the most using the most updated data ests reported worldwide. As a first step toward this purpose, the most reliable techniques commonly employed in the measurements of its concentration in the background atmosphere are introduced in combination with the flux measurement techniques over soil surface such as: dynamic enclosure (or field flux chamber) method and field micrometeorological method. Then the results derived using these measurement techniques are discussed and interpreted with an emphasis on its mobilization across the terrestrial biosphere and atmosphere interface. A unmber of factors including air/soil temperature, soil chemical composition, soil water content, and barometric pressure are found out to be influential to the rate and amount of such exchange processes. Although absolute magnitude of such exchange processes is insignificant relative to that of the major component like the oceanic environment, this exchange process is thought to be the the predominant natural pathway for both the mobilization and redistribution of atmospheric Hg on a local or regional scale.

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황사발생지역에서 토양입자의 화학적 특성 (Soil Chemical Properties in Asian Dust Source region in Northern China)

  • 한진석;신선아;공부주;박문수;박순웅;김수진
    • 환경영향평가
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    • 제13권6호
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    • pp.277-284
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    • 2004
  • The chemical composition and properties of soil were determined at selected sites, such as Loess plateau, Gobi and sand deserts in northern China, where most dust storms occur. Although the transport of this sort of dust storms to Korean peninsula is a well-documented phenomenon, there is not enough information about the very source regions. In this reason, this study tried to measure the chemical composition, including soil elements, anthropogenic elements and ions for soil samples so that certain properties of some major source regions of Asian Dust can be provided. Furthermore, the results are classified into four types of soil like Loess, Loess & sand, Gobi, and sand in order to identify the characteristics and difference among the types. $(X/Al)_{crust}$ values for each soil type were also calculated in this study and compared with those of other references including Asian Dust material(ADM). The results indicated that Ca contribution was higher than Al in all the soil types of this study including ADM and, compared with the values of urban area, contribution of anthropogenic elements such as Cr, Pb, Zn was quite low. However, it must be noted that there is such a variation in the result of soil composition, but it is also certain that the very source region soil composition resolved from this study could support the enhanced study on Asian Dust phenomenon in Korea.

청과물 저장에 관한 연구(제 2보) -사과 저장에 있어서 환경압력 및 기체조성이 사과조직내 기체조성과 Ethylene 생성에 미치는 영향- (A Study on the storage of Fresh Fruits and Vegetables (Part II) Effects of Intercellular atmosphere and Ethylene evolution by control of external pressure and gas composition in Apple Fruits.)

  • 손태화;최종욱;서온수
    • 한국미생물·생명공학회지
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    • 제1권1호
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    • pp.25-30
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    • 1973
  • 본 연구는 1971년과 1972년 9월 25일에 수확한 흥옥과 동년 10월 25일에 수확한 국광을 시료로하여 이들 사과의 저장에 있어서 환경압력 및 환경기체조성이 사과조직내 기체조성과 호흡 및 ethylene 생성에 미치는 영향을 규명하기 위하여 실험하였던 바 그 결과는 다음과 같다. 1. 과실조직내 기체량은 환경압력에 비례적으로 변화하며, 환경압력이 사과의 조직내 기체조성 및 기체량에 현저하게 영향을 미쳤다. 2. 조직내 $CO_2$발생량의 증가는 조직내 $O_2$ 소비량에 관련되며, 그러므로 내부 $O_2$ 소비의 감소되는 시기와 호흡에 있어서 climacteric rise의 시기와 일치하였다. 3. $CO_2$ 발생량의 증가는 ethylene 생성 후에 나타나며 그리고 상압구의 이와 같은 현상은 감압구에 잇달아 일어난다. 4. 감압저장에 있어서도 저산소농도와 고탄산가스농도의 조절로써 CA효과를 얻을 수 있다.

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서해안 대가 분진의 화학 조성 및 기원에 대한 연구 (1) (Chemical Composition and Sources of Atmospheric Particulates Collected on the West Coast of Korea)

  • 최만식;조성록;이동수
    • 한국대기환경학회지
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    • 제5권2호
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    • pp.72-83
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    • 1989
  • Twenty-five atmospheric particulates were collected using a high volume aerosol sampler from Septermber to December, 1988 on a site located on the West coast of Korea and analysed for twelve elements (Na, Mg, Al, Mn, Fe, Cu, Co, Ni, Zn, Ag, Cd, and Pb) by AAS. The particles being mainly crustal minerals, large quantity of spherical fly ashes were also observed. In order to identify the origin of trace metals in atmospheric particulates, enrichment factor, interelemental correlation and factor analysis were performed. Based upon these analysis, the twelve elements can be classified into three groups; the elements dominantly present in soil particles (Al, Mn, Fe, Co, and Ni), those in sea salt aerosols (Na and Mg), and those in air pollution-derived particles (Cu, Cd, Pb, Ag and Zn).

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청과물 저장에 관한 연구(제1보) -통기량 조절에 따른 저장실내 기체조성 및 생리화학적 변화에 대하여- (A Study on the Storage of Fresh Fruits and Vegetables (I) -Changes of the Internal Atmosphere in Storage Room and the Biochemical Changes of Apple Fruits by Controlled Ventilation-)

  • 손태화;최종욱;김성달
    • 한국식품과학회지
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    • 제4권1호
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    • pp.13-17
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    • 1972
  • This experiment was conducted to observe the changes of composition of atmosphere in storage room by controlled ventilation under normal and sub-atmospheric conditions, and the biochemical changes in apple texture under these conditions. The results were as follows; 1) By controlled ventilation, concentration of carbon dioxide in storage room was optionally regulated and constantly maintained. 2) Among compositions of internal atmosphere of apple, especially, concentration of ethylene was much decreased at apple stored under sub-atmospheric condition than that stored under normal atmospheric condition. 3) Acidity of apple stored under sub-atmospheric condition was much greater than that of apple stored under normal atmospheric condition. 4) Respiratory quotients of apple, which was stored under normal and sub-atmospheric conditions, were shown to be high. But decarboxylation of added pyruvate was found more active in slices prepared from apple stored under sub-atmospheric condition.

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인자분석을 통한 대기 입자상 물질의 입경별 발생원 추정-Drum impactor를 이용한 2002년 5월 제주도 고산지역 측정을 중심으로 (Size-segregated Sources of Aerosol Estimated by Factor Analysis-For the Measurement using Drum Impactor at Gosan, Jeju Island in May 2002)

  • 한진석;문광주;공부주;류성윤;김영준
    • 한국대기환경학회지
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    • 제20권5호
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    • pp.685-695
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    • 2004
  • Size-segregated measurements of aerosol composition are used to estimate the transport of natural and anthropogenic aerosols at Gosan site during May 2002. The results of measurement show that not only soil dust but also anthropogenic aerosols, including sulfur and enriched trace metals such as Pb, Zn, Cu, are transported to Gosan. This study combines the size- and time-resolved aerosol composition measurements with factor analysis in order to identify some source materials. As a result, coarse particles (2.5${\mu}m$~12${\mu}m$) are influenced by soil, sea-salt, coal, coal combustion, and nonferrous sources. But fine particles have different sources. The fine particles, which the diameter is from 0.56${\mu}m$ to 2.5${\mu}m$, are more affected by road dust, oil combustion, industry. municipal incineration, and ferrous metal sources. The very fine particles, from 0.09${\mu}m$ to 0.56${\mu}m$, mainly supplied by biomass burning, oil combustion, nonferrous and ferrous metal sources.

대기 플라즈마 용사공정을 이용한 Fe계 벌크 비정질 금속 코팅의 초기 분말의 화학조성과 크기에 대한 미세 조직 및 마모 특성 (Microstructure and Tribological Properties along with Chemical Composition and Size of Initial Powder in Fe-based BMG Coating through APS)

  • 김정환;윤상훈;나현택;이창희
    • 한국표면공학회지
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    • 제41권5호
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    • pp.220-225
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    • 2008
  • In this study, two kinds of Fe-based bulk metallic glasses (BMG) powder were built-up through atmospheric plasma spray (APS) technique. The microstructure of two coatings was analyzed through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Crystallization and oxidation in coatings were affected by chemical composition and initial powder size. Then, both of them influenced the tribological property.

Methodology to Simultaneously Optimize the Inlet Ozone Concentration to Oxidize NO and Relative Humidity Composition for the $NO_x$ Degradation using Soil Bio-filter

  • Cho, Ki-Chul;Hwang, Kyung-Chul
    • Journal of Korean Society for Atmospheric Environment
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    • 제24권E2호
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    • pp.83-91
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    • 2008
  • This work investigated the methodology to simultaneously optimize the ozone and relative humidity composition for the $NO_x$ degradation using soil biofilter. Experiments were made as a function of inlet ozone concentration ($0{\sim}1,770\;ppb$) and relative humidity ($38{\sim}81%$). Factorial design ($2^2+3$) and response surface methodology by central composite designs were used to examine the role of two factors and optimal response condition on $NO_x$ degradation. It was found that a second-order response surface model can properly interpret the experimental data with an $R^2$-value of 0.9730 and F-value of 71.83, based on which the maximum $NO_x$ degradation was predicted up to 92.8% within our experimental conditions.