• 제목/요약/키워드: soil dust

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단일입자분석 (Low-Z Electron Probe X-ray Microanalysis)을 이용한 2000년, 2001년에 발생한 황사 입자의 특성분석 (Single Particle Characterization of Aerosol Particles Collected During "Asian Dust" Storm Events in the Spring of 2000 and 2001, Using Low-Z Electron Probe X-ray Microanalysis)

  • 황희진;김혜경;노철언
    • 한국대기환경학회지
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    • 제19권4호
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    • pp.415-425
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    • 2003
  • A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

OPTICAL PROPERTIES OF ASIAN DUST AEROSOL DERIVED FROM SEAWIFS AND LIDAR OBSERVATIONS: A CASE STUDY OF DUST OVER CLOUDS

  • Fukushima, H.;Kobayashi, H.;Murayama, T.;Ohta, S.;Uno, I.
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.367-372
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    • 2002
  • Asian dust aerosol layer of 4-6 km altitude accompanied by low clouds was observed by LIDAR and sky-radiometer in Tokyo urban area on April 10, 2001. To synthesize the top of atmosphere (TOA) reflectance, radiative transfer simulation conducted assuming aerosol/cloud vertical structure and aerosol size distribution that were modeled after the ground observations. The refractive index of Asian dust is derived from a laboratory measurement of sampled Chinese soil particles. The synthesized TOA reflectance is compared to the SeaWiFS-derived one sampled at the low cloud pixels whose airmass is the same as the one passed at the observation site. While the two TOA reflectances compare generally well with few percent difference in reflectance, possible sources of the discrepancy are discussed.

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Reuse of dredged sediments as pavement materials by cement kiln dust and lime treatment

  • Yoobanpot, Naphol;Jamsawang, Pitthaya;Krairan, Krissakorn;Jongpradist, Pornkasem;Horpibulsuk, Suksun
    • Geomechanics and Engineering
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    • 제15권4호
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    • pp.1005-1016
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    • 2018
  • This paper presents an investigation on the properties of two types of cement kiln dust (CKD)-stabilized dredged sediments, silt and clay with a comparison to hydrated lime stabilization. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted to examine the optimal stabilizer content and classify the type of highway material. A strength development model of treated dredged sediments was performed. The influences of various stabilizer types and sediment types on UCS were interpreted with the aid of microstructural observations, including X-ray diffraction and scanning electron microscopy analysis. The results of the tests revealed that 6% of lime by dry weight can be suggested as optimal content for the improvement of clay and silt as selected materials. For CKD-stabilized sediment as soil cement subbase material, the use of 8% CKD was suggested as optimal content for clay, whereas 6% CKD was recommended for silt; the overall CBR value agreed with the UCS test. The reaction products calcium silicate hydrate and ettringite are the controlling mechanisms for the mechanical performance of CKD-stabilized sediments, whereas calcium aluminate hydrate is the control for lime-stabilized sediments. These results will contribute to the use of CKD as a sustainable and novel stabilizer for lime in highway material applications.

경험식을 이용한 발원지 황사의 시간별 발생량 추정 (Estimation of Hourly Emission Flux of Asian Dust Using Empirical Formulas in the Source Area)

  • 문윤섭;이승환
    • 한국대기환경학회지
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    • 제25권6호
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    • pp.539-549
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    • 2009
  • The purpose of this study is to estimate hourly Asian dust emission flux in springtime by using the optimized Weather Research Forecasting model (WRF) in order to accurately predict the horizontal flux of Asian dusts. Asian dust emission flux using 5 empirical formulas such as US EPA, Park and Inn, Wang, The Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Dust Entrainment and Deposition (DEAD) were calculated and compared by using classified land-use types and size distribution at various locations in China and Mongolia together with the hourly meteorological elements of the WRF model. As a result, the empirical formula in US EPA among them, which was considered the various conditions such as vegetation, soil type and terrain, was better than the other 4 empirical formulas. However, these formulas were adjusted hourly and vertically in time and space because there was different order and time resolution of dust emissions from original empirical formulas.

산업부산물을 이용한 지반고화제 혼합토의 강도특성 (Strength Characteristics of Solidified Soil with Hardening Agents made of Industrial By-Products)

  • 김영상;유근모;문경주
    • 한국지반환경공학회 논문집
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    • 제13권6호
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    • pp.19-26
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    • 2012
  • 본 연구에서는 산업부산물 중 고로슬래그를 기본 재료로 바이패스 더스트(Bypass dust), 플라이애쉬와 인산석고를 자극제로 활용하고 원료들 간의 화학적 상호작용을 이용하여 개발된 지반 고화제의 개량효과를 판단하기 위하여 화강풍화토 및 준설된 해성점토에 다양한 혼합비로 혼합하여 기본 물성실험과 일축압축실험을 실시하였다. 화강풍화토와 혼합하여 실험한 결과, 인산석고를 자극제로 활용한 B-2고화제가 바이패스 더스트를 자극제로 활용한 B-1고화제에 비해 우수한 강도를 발현하였다. 화강풍화토에 5~7%의 무게비로 혼합된 B-1 및 B-2고화제는 일반 포트랜트 시멘트(OPC)에 비해 44%~60%의 강도를 발현시키나 원료가 산업부산물이므로 특별히 높은 강도를 요구하지 않는 지반구조물에 사용된다면 시멘트뿐 아니라 현재 국내에서 판매되는 고화제에 비해 경제적인 것으로 판단된다. 또한 해성준설토에 5~14%로 혼합하여 실험한 결과, 양생일 및 혼합비 증가에 따라 혼합토의 강도는 증가하며 B-1 고화제의 경우 양생일에 대해 선형적으로 증가하여 14% 혼합비에서 28일 양생일의 일축압축강도가 OPC혼합토에 비해 40%의 강도를 보이나 B-2는 양생일에 대해 비선형적으로 증가하여 OPC 혼합토 대비 133%로 매우 큰 강도를 발현하였다. 한편 B-1혼합토와 B-2혼합토의 변형계수는 $E_{50}=(20{\sim}47)_{qu,28}$ 범위인 것으로 나타나 OPC 혼합 준설토의 하한계 값에 가까운 것으로 나타났다.

황사 배출량이 동아시아 지역 PM10 농도에 미치는 영향 (The Effect of Dust Emissions on PM10 Concentration in East Asia)

  • 최대련;구윤서;조진식;장영기;이재범;박현주
    • 한국대기환경학회지
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    • 제32권1호
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    • pp.32-45
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    • 2016
  • The anthropogenic aerosols originated from the pollutant emissions in the eastern part of China and dust emitted in northwestern China in Yellow sand regions are subsequently transported via eastward wind to the Korean peninsula and then these aerosols induce high $PM_{10}$ concentrations in Korean peninsula. In order to estimate air quality considering anthropogenic and dust emissions, Comprehensive Air-quality Model with extension (CAMx) was applied to simulate $PM_{10}$ concentration. The predicted $PM_{10}$ concentrations without/with dust emissions were compared with observations at ambient air quality monitoring sites in China and Korea for 2008. The predicted $PM_{10}$ concentrations with dust emissions could depict the variation of measured $PM_{10}$ especially during Yellow sand events in Korea. The comparisons also showed that predicted $PM_{10}$ concentrations without dust emissions were under-predicted while predictions of $PM_{10}$ concentrations with dust emission were in good agreement with observations. This implied that dust emissions from desert and barren soil in southern Mongolia and northern China minimized the discrepancies in the $PM_{10}$ predictions in East Asia. The effect of dust emission on annual $PM_{10}$ concentrations in Korea Peninsula for year 2008 was $5{\sim}10{\mu}g/m^3$, which were about 20% of observed annual $PM_{10}$ concentrations.

서울지역의 황사발생시 호흡성 분진 중 미량원소의 특성 평가 (Trace Metals Characterization of Respirable Dust during Yellow Sand Phenomena in Seoul Area)

  • 신은상;선우영
    • 환경위생공학
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    • 제17권1호
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    • pp.41-51
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    • 2002
  • This research was carried out using Anderson air sampler which were set up on the roof of the Engineering College of Konkuk University at Hwayang-Dong, Kwangjin-Gu, Seoul from Aug. 1992 to foul. 1999. The results are as follows: The major component of yellow sand is soil particles based upon the observation that particles ranging from $3.3~7.0{\mu}m$ occupy 36~63%. It is certain that the increase of fine particles of respirable dust during yellow sand phenomenon in Seoul area affects the human body. The trace metals from natural sources like Al, Ca, Fe, K, Na, and Si show larger mass median diameter(MMD) values during yellow sand phenomenon than in normal situations while the values of MMD for Mn and Pb rarely changes. Noticeably, the changes in value of MMD of water soluble elements like ${NO_3}^{-}$ and ${SO_4}^{2}$ are 2.3 and 6.6 times higher during the yellow sand phenomenon compared to normal situations, respectively. This fact is regarded as decisive evidence showing that ${NO_3}^{-}$ and ${SO_4}^{2}$ in the air are attached to yellow sand and move together.

천연 다당류 먼지포집제를 이용한 지하철 터널 내 PM10 제어에 대한 연구 (A Study on PM10 Control in Subway Tunnels Using Natural Polysaccharide Dust Collecting Agent)

  • 이한섭;황수진;황현석
    • 한국환경보건학회지
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    • 제43권2호
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    • pp.122-129
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    • 2017
  • Objectives: Most of the $PM_{10}$ in subway stations is spread by the train-induced wind from the tunnels. Therefore, in order to improve air quality in subway stations, it is important to remove the $PM_{10}$ from the tunnels. After the installation of PSD (platform screen doors), the influence of train-induced wind and $PM_{10}$ at the platform has decreased, but is estimated to have increased in subway tunnels. This study was conducted to investigate the control of $PM_{10}$ in subway tunnels by applying a 500-fold diluted solution mixed with a humectant using a natural polymer. Methods: For this purpose, we tested the dust reduction effect in a laboratory and corrosion test and water pollution using fish and aquatic plants for the natural dust collecting agent. In the tunnel of a subway station, we used the natural dust collecting agent over 15 days. The study was carried out on $PM_{10}$ control during operation, which accounts for more than 70% of subway dust. Results: As results, the natural dust collecting agent exhibited an excellent dust control effect, and it was safe for water quality and soil. It showed the effect of controlling $PM_{10}$ in the subway tunnel by 49.5- 64.7% over 15 days. The use of the dust collecting agent for the control of $PM_{10}$ could be confirmed in the subway. Conclusion: It is necessary to clearly explain the major portions of chemical components contained in $PM_{10}$ to figure out the characteristics of $PM_{10}$ and to develop effective reduction measures to decrease the adverse effects of $PM_{10}$ in the subway.

중국 기원 광물성 먼지 입자의 지화학 추적자 개발 및 기초 적용연구 (Development of Geochemical Tracers to Identify a Specific Source Region of Mineral Dust in China and Preliminary Test of Their Applicability)

  • 이소정;형기성;김원년;김태훈
    • Ocean and Polar Research
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    • 제41권3호
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    • pp.169-181
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    • 2019
  • The purpose of this study is to develop geochemical tracers to identify a specific source desert of mineral dust in China using the published data. In addition, we tested the applicability of these tracers to wet-deposits and soil samples collected in Jeju, Korea. Because of similarity in trace elemental compositions of mineral dust from the major arid regions in China, such as Taklimakan, West Ordos (Badain Jaran), East Ordos (Mu Us and Hobq), East Northern China (Horqin), West Northern China (Gurbantunggut), and Chinese Loess Plateau, there has been limited to the use of geochemical data for source identification. Here we propose the four (4) plots using combination of seven (7) geochemical variables as a source indicator to distinguish one from other source regions in China: $\frac{Y}{Tb_N}$ vs. $\frac{Th}{{\Sigma}REE_N}$, $\(\frac{La}{Gd}\)_N$ vs. $\frac{Y}{{\Sigma}REE_N}$, $\frac{Th}{Tb_N}$ vs. $\frac{Y}{Nd_N}$, and $\frac{Th}{Tb_N}$ vs. $\(\frac{Ce}{Ce}\)_N^*$, where $_N$ and $\(\frac{Ce}{Ce}\)_N^*$ stand for values normalized to Post-Archean Average Shale composition and Ce anomaly, respectively. Mineral dusts from aforementioned six major deserts are distinguished one from the others by the combined use of these variables. Jeju rock and soil samples form a separate domain from Chinese mineral dusts in all four plots. In contrast, most of Jeju dust samples were comparable with the West Ordos desert (Badain Jaran) domain, indicative of strong influence of Badain Jaran dust in Jeju in spring season when the mineral dust was collected. A weak positive Ce anomaly in Jeju samples implies minimal local contribution. Our study suggests that the combination of $\frac{Y}{Tb_N}$ vs. $\frac{Th}{{\Sigma}REE_N}$, $\(\frac{La}{Gd}\)_N$ vs. $\frac{Y}{{\Sigma}REE_N}$, $\frac{Th}{Tb_N}$ vs. $\frac{Y}{Nd_N}$, and $\frac{Th}{Tb_N}$ vs. $\(\frac{Ce}{Ce}\)_N^*$ can be used to identify a specific source region of mineral dust in China as well as Jeju mineral particles.