• 한국대기환경학회지
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• 제21권6호
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• pp.657-666
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• 2005

The objectives of this study were to investigate atmospheric dry deposition of inorganic nitrogen-containing compounds to waterbody. Target waterbody is Juam reservoir functioning as one of the major water supply sources in Chollanamdo. Nitrate and ammonium dry deposition fluxes were directly measured using dry deposition plate (DDP) covered with greased strips and a water surface sampler (WSS). The daytime average $NO_{3}^{-}\;and\;NH_{4}^{+}$ fluxes measured with DDP and WSS were $1.7\∼2.6$ times higher than those at nighttime. The seasonal average flux of $NH_{4}^{+}$ showed the highest value in summer. The daytime and nighttime average dry deposition fluxes of particulate phase Nitogen-containing Compounds ($1.13,\;0.80\;mg/m^{2}$ day) were much higher than those of gas phase compounds ($0.50,\;0.24\;mg/m^{2}$ day).

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.270-282
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• 2017

To evaluate the deposition amount on a ground surface, mesoscale numerical models coupled with atmospheric chemistry are widely used for larger horizontal domains ranging from a few to several hundreds of kilometers; however, these models are rarely applied to high-resolution simulations. In this study, the performance of a dry and wet deposition model is investigated to estimate the amount of deposition via computational fluid dynamics (CFD) models with high grid resolution. Reynolds-averaged Navier-Stokes (RANS) simulations are implemented for a cone and a two-dimensional ridge to estimate the dry deposition rate, and a constant deposition velocity is used to obtain the dry deposition flux. The results show that the dry deposition rate of RANS generally corresponds to that observed in wind-tunnel experiments. For the wet deposition model, the transport equation of a new scalar concentration scavenged by rain droplets is developed and used instead of the scalar concentration scavenged by raindrops falling to the ground surface just below the scavenging point, which is normally used in mesoscale numerical models. A sensitivity analysis of the proposed wet deposition procedure is implemented. The result indicates the applicability of RANS for high-resolution grids considering the effect of terrains on the wet deposition.

• 한국대기환경학회지
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• 제14권5호
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• pp.421-432
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• 1998

Deposition processes limit the life time of pollutants in the atmosphere and control the distance travelled before deposition. Thus the understanding about atmospheric deposition processes is essential for a proper assessment of the environmental impacts due to the anthropogenic pollutants. The dry deposition velocities are related to surface types, atmospheric stabilities, friction velocities, air pollutants and so on. In this study we simulated the dry deposition velocities of O3 in Pusan region. The calculated deposition velocities compared to the observed O3 data obtained during the summer of 1988 over a deciduous forest in Canada. The comparison showed that the model somewhat overpredicted deposition velocities for the average diurnal variations with maxima in daytime and minima in nighttime mostly due to the turbulence intensity.

• 한국대기환경학회지
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• 제16권5호
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• pp.445-451
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• 2000

To estimate dry deposition flux of 12 elements in aerosols, aerosol particles were sampled by a low-pressure impactor(LPI) and a dust jar. The concentrations of 12 elements in aerosol particle and dry deposition were analyzed by a PIXE analysis using as a 2.0 MeV-proton beam. The mean dry deposition velocities of 12 elements were estimated by ranges of 0.74∼2.62 cm/sec. The results showed that the highest value was 3.26 cm/sec for Ca and the lowest value 0.74 cm/sec for Fe. The dry deposition flux for elements was calculated as a function of particle size by 1-step method and 12-step method. In this work, dry deposition velocities were computed with the two existing models; the coarse-particle fraction(4∼30 mm diameter) using the dry deposition velocity model of the Noll and Fang(1998) and the fine-particle fraction (0.05∼4mm diameter) using the Shemel and Hodgson(1980) model. The ratios of the mean calculated/measured fluxes were 3.59 for 1-step method and 0.60 for 12-step method respectively.

• 한국대기환경학회지
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• 제16권6호
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• pp.675-684
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• 2000

A novel dry and wet deposition collector, which can overcome the several problems such as water evaporation cartridge cracks and high costs founded in the previous collector systems, has been constructed. ENVI-18 SPE adsorption cartridge has been used to measure atmospheric deposition of polycylic aromatic hydrocarbons (PAHs). A surrogate surface, consisted of water and methanol, was filled in the dry deposition funnel to simulate dry deposition onto water surface. A water supply system in order to compensat evaporation of the surrogate surface was used and it was consisted of a piston pump, a tubing pump, a overflow tube and a chamber system. A novel water vaporizing system to supply water onto the wet SPE cartridge system with a constant flow rate was developed. The novel water vaporizing system, consisted of a vacuum pump, a water supply reserviour and tube and a mini space heater, could prevent the PAHs adsorption cartridge cracks occurred in the previous collector and effectively adsorb PAHs. The novel dry and wet deposition collector showed a good adsorption, desorption, and recovery rates of PAHs. By reducing the number of pumps used and employing polypyopylene (PP) instead of teflon as a material of collection funnel, the total construction costs were much reduced as compared with the previous dry and wet deposition collectors.

• 한국대기환경학회지
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• 제14권5호
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• pp.465-478
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• 1998

In this study, seasonal variations of the dry deposition velocity and deposition flux for the sulfur dioxide were analysed. The field observation was performed during one year (from November 1, 1995 to October 31, 1996) in Chunchon basin. The turbulence data were measured by 3-dimensional sonic anemometer/thermometer, and were estimated by mean meteorological data obtained at two heights (2.5 m and 10 m) of meteorological tower. Also, the estimation methods were evaluated by comparing the turbulence data. The results showed that the estimated dry deposition velocity and turbulence parameter such as uc and sensible heat flux using mean meteorological data were relatively similar to the sonic measurements, but all showed somewhat large differences. The dry deposition velocity was large in summer and small in winter mainly due to canopy resistance (rc). The major factor which affects diurnal variation of the velocity was aerodynamic resistance (rw). The SO2 dry deposition flux was large in winter and small in summer in Chunchon.

• 한국대기환경학회지
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• 제17권1호
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• pp.19-29
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• 2001

Atmospheric concentrations of acidic pollutant were measured by the 4 stage filter pak method at Chunchon and by the 3 stage filter pack method at Seoul and Anmyon-do from January to December 1998. The sample was collected for 24 hours on every Wednesday. Concentrations of particulate matters were highest at Anmyon-do. The particulate concentration was much higher during the warm season than other seasons. While the particulate concentration was higher during the warm season, the concentration of gaseous matter was higher in winter. Dry deposition flux was calculated by using reported deposition velocities and concentration of pollutants measured in this study. The dry deposition velocities used in this study for SO$_2$, SO$_{4}^{2}$, HNO$_3$,NO$_{3}^{-}$ and NH$_3$ were 0.29, 0.15, 2.08( 2.13 only for Anmyon-do), 0.20 and 1.00cm/sec, respectively. At Chunchon, annual sulfur flux originated from dry deposition was 384 kg/$textrm{km}^2$, and the flux from wet deposition was 782kg/$textrm{km}^2$. Dry deposition of sulfur was 33% of total sulfur deposition. The annual nitrogen flux originated from dry deposition was 1,892kg/$textrm{km}^2$. And the flux from wet deposition was 1,066kg/$textrm{km}^2$. Dry deposition of nitrogen was 64% of total nitrogen deposition. Dry deposition as well as wet deposition have to be considerd in the study on acidification of environment such as soil or watershed.

• 한국대기환경학회지
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• 제21권1호
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• pp.39-48
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• 2005

Nitrogen and sulfur deposition was measured on Lake Pal dang from March 2002 to October 2003. Wet and dry depositions were separately measured using wet- and dry-only samplers, respectively. In order to measure the dry deposition to the water body, a dry deposition sampler composed of three pans filled with pure water, called the deposition water, was used. Since ammonium was generally in excess in ambient air, more than half of ammonium was present in the gaseous form. Ammonium concentration was also generally higher than the sum of major anion concentrations in the deposition water because gaseous species were much easily deposited than the species in fine particles. Nevertheless, the contribution of gaseous ammonia to the deposition of ammonium was not high as well as that of particulate ammonium while the contribution of gaseous nitric acid was much higher than that of particulate nitrate. Annual wet deposition fluxes of nitrogen and sulfur were five and six times higher than their dry deposition fluxes, respectively. Except for ammonium, the dry deposition flux estimated in the present work was a half of the previous results. This was mainly caused by much smaller dry deposition velocities over the water than over the ground.

• 한국대기환경학회지
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• 제12권1호
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• pp.101-112
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• 1996

Dry and wet deposition is an impertant removal mechanism of the amobient aerosol in the atmospheric environment. Since the deposition flut provides adverse impacts on various encironmental media including aquatic and ecological system as well as human health, it is essential to quantitatively estimate the removal fluxes of many air pollutants. Thus, the purposes of this experimental study are to investigate seasonal deposition flux variations of the total dustfall and various inorganic elements in the local ambient air and then to finally estimate their dry deposition velocities. To perform the study, the total of 90 dustfall samples were collected from January, 1994 thru February, 1995 in 5 different cities of Korea including Seoul, Suwon, Daejon, Kwangju, and Kangrung. Each sample was analyzed by an AAS and an ICP to determine the quantities of the 11 inorganic elements, such as Zn, Cd, Cr, K, Na, Pb, Ca, Fe, Mn, Mi, and Cu. As results, deposition fluxes, soluble/insoluble fractions, and deposition velocities for each element were extensively investigated. The resulting dry deposition velocities of some elements in Suwon were estimated by ranges of 0.57 .sim. 0.87 cm/sec for Zn, 0.35 .sim. 0.45 cm/sec for Pb, 1.25 .sim. 3.52 cm/sec for Ca, 0.21 .sim. 0.48 cm/sec for Fe, 0.95 .sim. 9.31 cm/sec for Mn, and 2.08 cm/sec for Cu.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E1호
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• pp.35-43
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• 2006

Ambient particle size distributions of PCBs and their dry deposition fluxes were measured at a site in Seoul to quantify dry deposition fluxes of PCBs and size characteristics of PCBs in the air, and to estimate ambient concentrations of gaseous PCBs and dry deposition fluxes. The dry deposition plate was used to measure dry deposition fluxes of particulate mass and PCBs and a cascade impactor and rotary impactor were used to measure ambient particle size distributions for small ($D_p<9{\mu}m$) and large ($D_p>9{\mu}m$) particles, respectively. Six sample sets were collected from April to July 1999. The fluxes of particulate total PCBs (the sum of 43 congeners) ranged from 160 to $607ng\;m^{-2}day^{-1}$. The size distribution of total PCBs was bimodal with two peaks in small particle size ($D_p{\sim}0.6\;and\;6{\mu}m$, respectively) and, thus, mass concentration being dominant in small particles. The mean particulate PCBs concentration was $6.9{\mu}g$ PCBs/g. The concentrations of PCB homologues in the gas phase were estimated based on the particle/gas partition coefficient ($K_p$) with the measured values of particulate PCBs in this study and they were comparable to those observed in other previous studies. Dry deposition fluxes were estimated by calculating dry deposition velocities.