• Title/Summary/Keyword: Dry deposition

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Preliminary Estimation of Particle Dry Deposition Fluxes along Coastal Area of Jeju Island

  • Lee, Ki-Ho;Hu, Chul-Goo
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.10 no.S_2
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    • pp.55-63
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    • 2001
  • This work employs two models to quantify the size-segregated dry deposition fluxes of particle-bound N $O_3$$^{[-10]}$ , N $H_4$$^{+}$, and S $O_4$$^{2-}$ along the coastal area of Jeju Island based on the chemical composition data of aerosol collected during the springtime of 1995. The two approaches produced fairly comparable results, despite the feature differences between the two models. The modelling results obtained indicated that the mean dry deposition velocity was around 0.4 cm $s^{-1}$ for N $O_3$$^{[-10]}$ , 0.2 cm $s^{-1}$ for N $H_4$$^{+}$, and 0.3 cm $s^{-1}$ for S $O_4$$^{2-}$, and the dry deposition flux varied between 371~1368 $\mu\textrm{g}$ $m^{-2}$ da $y^{-1}$ for nitrate, 28~625 $\mu\textrm{g}$ $m^{-2}$ da $y^{-1}$ for ammonium, and 957~6088 $\mu\textrm{g}$ $m^{-2}$ da $y^{-1}$ for sulfate. Although difficulties in collecting giant and/or fine particles limited the understanding of the mass size distribution of particles and thus the ability to refine estimates of the dry deposition flux for the particulate matter, both models were still able to offer sufficient realism to explain the features of the available data collected from the coastal area of Jeju Island.and.

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The Numerical Simulation of Dry Deposition Velocity Of O3 using Land-Use Information in the Busan Metropolitan City (지표면 특성을 고려한 부산지역의 건성침적속도 예측)

  • 문난경;이화운
    • Journal of Environmental Science International
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    • v.11 no.9
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    • pp.925-931
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    • 2002
  • Land-use types should be included in air pollutant diffusion model because a complex mixture of various land-use patterns with computational grid can make errors in calculation of several parameters. However, the air pollutant diffusion model has generally been treated with a uniform component with land-use type in each mesh because of the complexity of the simulation. This study presents a numerical simulation of the horizontal distribution of $O_3$dry deposition velocity during summertime in Busan metropolitan city. The calculation of the meteorological field was conducted using the land cover data. Simulation has been performed by the following two scenarios : (1) one with current land cover data, and (2) the other with only land and sea for the surface characteristics. The results from each scenario reveals considerable differences on the meteorological fields and these differences can cause changes in the calculation values of $O_3$deposition velocity.

A Study on the Dry Deposition Model of Air Pollutants Considering Canopy Effect (Canopy를 고려한 대기오염물질의 건성침적모델에 관한 연구)

  • 이화운;박종길
    • Journal of Environmental Science International
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    • v.4 no.2
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    • pp.151-158
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    • 1995
  • A numerical model has been developed to predict the deposition of air pollutants considering canopy effect. In this model, the deposition velocity is calculated using the deposition resistances(aerodynamic resistance, viscosity resistance, surface resistance). Using the results, a comparative study was made between the model calculation and observation results. The calculated daily variation of deposition resistances and in daytime most of the model cases are well agreed with observation results, and a slight difference was found in nighttime. From the results, it is suggested that the present model is capable of estimating the deposition velocity of air Pollutants considering characteristics of canopy layer.

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Measurement of Dry Deposition of Polycyclic Aromatic Hydrocarbons in Jeoniu (전주지역에서 다환방향족 탄화수소의 건식 침적 측정)

  • Kim, Hyoung-Seop;Kim, Jong-Guk;Ghim, Young-Sung
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.2
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    • pp.242-249
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    • 2007
  • Deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) were measured at the Chonbuk National University located in Jeonju between June and November 2002. Fluxes of gaseous and particulate PAHs were separately obtained using a water surface sampler (WSS) and a dry deposition plate (DDP). Most of PAHs were deposited in the gaseous form since the low molecular weight PAHs dominates in the atmosphere. The deposition velocity of particulate PAHs was higher than that of gaseous PAHs when the molecular weight was low, but substantially decreased as the fine particle fraction increased with molecular weight. The deposition velocity was generally higher at high wind speeds. However, increase in the deposition velocity in unstable atmospheric conditions was also observed for gaseous PAHs of intermediate molecular weight.

A Study on the Quantitative Analysis of SO$_2$ Dry Deposition in the Northeastern Asia (동북아 지역에서의 SO$_2$ 건성 침적에 관한 정량분석)

  • 홍민선;김순태;이동섭
    • Journal of Korean Society for Atmospheric Environment
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    • v.13 no.3
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    • pp.231-241
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    • 1997
  • A tracer model was applied in the Far East Asia to investigate the dry deposition rates of air pollutants on Korean Peninsula originated from different countries including China and Japan. Wind direction was chosen to predict the maximum deposition rates and SO$_2$ was chosen as a tracer to estimate the source strength. Model simulation shows that inflow, deposition and airborne ratios of China-originated SO$_2$ were 50%, 8% and 30%, respectively, at most. Also it was found that deposition, outbounded and airborne ratios of Korea-originated SO$_2$ were 15~77%, 8~75%, and 3~30%, respectively Model simulation also shows that inflow, deposition and airborne ratios of Kyushu-originated SO$_2$ were, 30~45%, 8~14% and 20~25%, respectively. This study shows that tracer model can be applied on the estimation of air pollutants partitioning in regional scale and that more sophisticated modules and schemes can be developed and applied to better predict the transboundary amounts of air pollutants in this region.

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A Study of Air Pollutants Dry Deposition (대기오염물질의 건성침적에 관한 연구)

  • Lee, Chi-Young;Kang, Dong-Ku
    • Journal of environmental and Sanitary engineering
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    • v.18 no.3 s.49
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    • pp.64-68
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    • 2003
  • Measurement of dried deposition for air pollutant was investigated in Gwang-ju Health college area for a year. The average value of air pollutants was investigated three times a month. Measured heavy metals and concentration of mass are not corelated. Heavy metals were thrown up air as state of large particles and they were moved by wind. Deposition of heavy metals and deposition velocities were high in the order of Fe > n > Cu > Pb > Cr and Pb > Fe > Cr > Zn > Cu, respectively. The pattems of deposition velocity of heavy metals for a year were much the same as each other except that Pb is faster than others.

A Modeling Study on the Transport of Acid Pollutant by Regional Acid Deposition Model -Spacial Pattern and Variation of Air Pollutants on Eastern Asia and Central Part of Korea- (산성우모델에 의한 산성강하물의 수송에 관한 연구 - 동아시아 및 우리나라 중부지방의 대기오염물질 시공간분포 -)

  • Lee, Chong Bum;Cho, Chang Rae;Byun, Dae Won
    • Journal of Environmental Impact Assessment
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    • v.8 no.1
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    • pp.1-16
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    • 1999
  • The acid deposition and photochemical modeling study was performed on the Eastern Asia using Regional Acid Deposition Model(RADM). The results of this study show that horizontal distribution of $SO_2$, concentration and dry deposition flux was higher in Beking, Shanghai and central part of Korea. However distribution pattern of sulfate and $O_3$ concentration calculated by RADM were not similar to emission pattern. In daytime, $SO_2$, sulfate and $O_3$ were mixed to whole PBL but in nighttime because of inversion layer these pollutants were suppressed to lower level.

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The Importance of Dry Deposition : Dry Deposition Fluxes of Heavy Metals In Seoul, Korea During Yellow-Sand Events

  • Yi, Seung-Muk
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2003.06a
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    • pp.76-85
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    • 2003
  • Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates and a cascade impactor, from March to November 1998 in Seoul, Korea. During the spring sampling period several yellow sand events characterized by long range transport from China and Mongolia impacted the area. During these events the mass fluxes were statistically the same as during springtime non-yellow-sand events. However, most elemental fluxes were higher. In general, the flux ratios of both crustal (Al, Ca, Mn) and anthropogenic elements (Ni, Pb) to total mass measured during the daytime yellow-sand events were substantially higher than those measured in spring daytime during non-yellow-sand time periods. During all seasons the average measured daytime fluxes were about two times higher than at nighttime. The flux of primarily anthropogenic metals (Cu, Ni, Pb, Zn) and Mn was on average one to two orders of magnitude lower than the flux of the crustal metals Al and Ca. As is typically found two modes, fine (0.1∼l.0 $\mu\textrm{m}$) and coarse (1.0∼10.0 $\mu\textrm{m}$) were present in the measured size distributions (<10 $\mu\textrm{m}$). The particles in the coarse mode constitute a major portion of the measured mass size distribution during the yellow-sand events possibly due to the long-range transport of those particles from China.

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Mercury Fluxes from the Nan-Ji-Do Area of Seoul -Application of Micrometerorological Methods (미기상학적 기법을 응용한 난지도지역이 수은교환율 측정연구)

  • 김민영;김기현;이강웅;정일현
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.6
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    • pp.585-594
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    • 2000
  • Through an application of Micrometerorological methods, we conducted measurements of Hg fluxes from Nan-Ji-Do which is well known as one of the major local areal sources in Seoul metropolitan area during Match/April of 2000. In the course of our study, we determined the concentration gradients of total gaseous Hg(between 20 and 2000 cm heights) and combined these data with Micrometerorological components to derive is fluxes. It turned out that emission from and dry deposition to soil surfaces occurred at the ratio of 72:27 from a total of 271 hourly measurements. The validity of measured concentration gradients( or resulting fluxes) was evaluated in terms of percent gradient. Accordingly, about more than 95% of gradient data derived were statistically significant. The mean fluxes of Hg across soil-air interface, when computed using the concentrations gradients and relevant parameters, were found at 253(during emission) and -846ng/$m^2$/h(during dry deposition) The occurrences of abnormalously high exchange rates appear to be the combined effects of enormously high gradient values and high transfer coefficients. While the emissions of Hg occurred constantly during the whole study periods, the occurrences of dry deposition events were observed most intensively during very limited time periods(3/29 and 4/3). The results of our study cleary indicated that the studied area is a strong local areal source, while exhibiting great potential as a major sink simultaneously.

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