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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society for Atmospheric Environment
Journal Basic Information
Journal DOI :
Korean Society for Atmospheric Environment
Editor in Chief :
Volume & Issues
Volume 16, Issue 4 - Aug 2000
Volume 16, Issue 6 - Jun 2000
Volume 16, Issue 3 - Jun 2000
Volume 16, Issue 5 - May 2000
Volume 16, Issue 2 - Apr 2000
Volume 16, Issue 1 - Feb 2000
Volume 6, Issue 6 - 00 2000
Volume 6, Issue 5 - 00 2000
Volume 6, Issue 4 - 00 2000
Volume 6, Issue 3 - 00 2000
Volume 16, Issue E - 00 2000
Volume 16, Issue E2 - 00 2000
Selecting the target year
Simulation of Atmospheric Dispersion over the Yosu Area -I. Terrain Effects-
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 211~223
The atmospheric dispersion of a pollutant emitted from a hypothetical source located in the middle of the Yochon Industrial Estate was simulated by using the Regional Atmospheric Modeling System (RAMS). Four horizontally nested grids were employed: the coarsest one covered the southern part of the Korean Peninsula including Mt. Chiri and the finest one covered the Yochon Industrial Estate and the surrounding area. Wind fields were initially assumed horizontally homogeneous with a wind speed of 4m/s, the average for the Yosu area, and were developed without both external forces and diurnal changes in order to investigate the terrain-induced phenomena. Wind directions that could emphasize the terrain effects on the pollutant transport and that could carry pollutants to a highly-popluated area were selected for the dispersion study. A pollutant was released for 24hours from a grid-base volume source after a 24-h blank run for developing the wind field. The dispersion study showed that the pollutant from the present source location did not directly affect the Yosu City, but showed high concentrations at locations behind the hills 5 to 6 km away from the source according to wind directions. When the wind speed was low, close to calm condition, the pollutant was detected at upstream locations 6 to 7 km from the source. In comparison with the results from the RAMS simulation, the Industrial Source Complex Short-Term Model(ISCST3) predicted a narrow dispersion that was sensitive to the wind direction. When the wind velocity was affected by the local environment, the ISCST3 calculation using that data also gave a lop-sided result, which was different from the distribution of the pollutant reproduced by RAMS.
Simulation of Atmospheric Dispersion over the Yosu Area -II. Diurnal Variations by Solar Radiation-
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 225~236
Diurnal variations of wind field and pollutant dispersion over the Yosu area under the insolation conditions of summer and winter were investigated by using the Regional Atmospheric Modeling System (RAMS). Initially, horizontally homogeneous wind field were assumed on the basis of sounding data at the Kwangju upper-air station for days whose morning wind speeds were below 2m/s. In these days, the sea breeze prevailed in summer while the land breeze lasted for a few hours in the morning; the effect of synoptic winds was strong in winter with some inclusion of wind variations owing to the interaction between sea and land. The predicted wind direction at the location of the Yosu weather station captured an important change of the sea-land breeze of the observed one. The predicted wind speed and the air temperature agreed with observed ones in a reasonable range. In the morning, both in summer and winter, winds around the source location were diverged and became weak between the mountainous area to the southeast and the Kwangyang Bay to the north. Winds, however, accelerated while blowing to the east and south and blowing on the mountainous area. Complicated wind fields resulted in high pollutant concentrations at almost all receptors considered. These high concentrations in the morning were even comparable to the ISCST3 calculations with the worst-case and typical meteorological conditions designated by USEPA(1996). On the other hand, in the afternoon, the wind field was rather uniform even in the mountainous area with development of mixing layer and the concentration distributions being close to the Gaussian distributions.
An Experimental Study on the Variation of Vertical Dispersion within Boundary Layer with Surface Roughness
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 237~246
An experimental study has been carried out using a rotating water channel in order to investigate the effect of surface roughness on the vertical dispersion of plume within boundary layer. Dispersion measurements of tracers released from two sources with different height at neutral conditions over various rough terrain ranging from rural to urban have been performed. Various values of roughness length were simulated by combining of 4 stream velocities and 3 roughness element conditions. Dispersion measurements have also been made for rough terrain where high buildings are locally concentrated. Values of
z increase with roughness and this tendency appears to apply both cases of with and without locally concentrated high buildings. The comparisons of the Bowne's nomogram on
2 vs x relationship and the measurements of
2 with roughness show good accordance in
2 distribution at stability D class over rural, suburban and urban terrain. For constant roughness length the
2 values of plumes from lower source height are smaller than those of plumes from higher source at short downwind distance, but this relationship becomes reverse as distance increases. Crossing appears to be made before about 2km. The value of constant I in McMullen's equation
2=exp [I+J(In x) + K(In x)2] appears to increase with roughness length, however, the relationships between other constants and roughness have been confirmed. The values of
2 for various downwind distances, estimated by using an equation which is employed in ISC (Industrial Source Complex) dispersion model for areas where high buildings are locally assembled, are in accordance with measurements from water channel experiments.
Characteristics of Non-Thermal Plasma Process for Air Pollution Control
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 247~256
Basic characteristics of non-thermal plasma process to remove C2H4 and NO have been experimentally investigated with a packed-bed type reactor and an ac power supply. The performance of the non-thermal plasma generated by ac power supply was compared with that of a wire-plate type reactor equipped with a pulsed power supply. The result shows that the non-thermal plasma can be effectively generated with an AC power supply that can be easily fabricated with conventional techniques. In order to understand the basic reaction mechanisms of the non-thermal plasma process, parametric tests for different carrier gases(air and nitrogen) and for different reaction pathways have been performed. The test results show that O3 generated by non-thermal plasma plays an dominant role to oxidize C2H4 and NO over N and O radicals when these pollutant gases are carried by dry air under room temperature condition. Experimental observations, however, indicate that N and O radicals can significantly affect on the removal process of the pollutant gases under certain conditions.
A Conversion Rate Prediction Study of Exhaust Gas by Catalyst Simulation in Heavy Duty Natural Gas Vehicle
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 257~264
An aftertreatment device which reduce exhaust gas of natural gas vehicle(NGV), NGV catalyst has important meaning as to reduce the exhaust emission. In this study, the characteristics of NGV catalyst were investigated and the effect parameters of NGV catalyst were analyzed and were predicted by changing the various parameters such as temperature, and gas concentration. The conversion efficiency of NGV catalyst converter was also predicted by Pd-loading, mass flow rate and gas composition.
A Study on Evaluation of Accuracy and Precision on B, T, X Analysis Using Thermal Desorption/Gas Chromatograph/Flams Ionization Detector
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 265~275
By using thermal desorption/gas chromatograph/flame ionization detector(TD/GC/FID), this study was carried out to evalute an accuracy and a precision on Benzene(B), Toluene(T), o-Xylene(X) analysis in an industrial hygiene laboratory. Limits of detection of TD/GC/FID on B, T, X were showed 13.75ng/sample or less. For the accuracy of the method by concentration levels, overall bias was showed 7.7% as an absolute value, and the pooled coefficient of variation showed 3.51%. For the precision on repeatability of peak area and retention time between within-run and between-run of analytical system, it is showed the results of within-run gave better than those of between-run. Also the accuracy by sorbents(Tenax TA and Chromosorb 106)was evaluated, and the precision on reproducibility between MDHS72 and this study was compared. It is showed it is possible for TD/GC/FID to evaluate accurately B, T, X concentration levels of less than 1ppm at indoor or outdoor of workplaces in Korea.
A Exhaust Gas Study by EGR in Heavy-Duty Diesel Engine
Journal of Korean Society for Atmospheric Environment, volume 16, issue 3, 2000, Pages 285~291
EGR(Exhaust Gas Recirculation) is known as the technique reducing the NOx emissions from diesel engine. Low pressure roote and high pressure roote are applied for heavy-duty diesel engine are. In this study, as research for the heavy duty diesel engine equipped with EGR, reduction characteristic of CO, THC, NOx, and PM in HD diesel engines are investigated by applying EGR device. Also, through the experiments using 11 liters, turbocharged diesel engine with EGR valve and intercooler, exhaust gas reduction characteristics were measured as changing in EGR rate according to D-13 mode.