• Journal of Korean Society for Atmospheric Environment
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• v.17 no.1
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• pp.105-115
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• 2001

This study was conducted to analyzed the pattern of $CO_2$ concentration changes in various time scale within and across the Korean Peninsula. We compared that data sets obtained from Moo-Ahn(NAN) station in Korea with those determined from major background observatory stations around the world from the periods of Aug. 1995 to Dec. 1997. The mean $CO_2$concentrations of the MAN area, if computed using the total of 884 daily mean values, were computed to by 374.5$\pm$6.6 ppm. When the background data for MAN were compared with those of other background site, the concentration of MAN was systematically higher than any other comparable sites. Results of correlation analysis between MAN and other background sites generally showed up the existence of strong correlations, indicating that the relative effect of $CO_2$ concentration change can proceed similarly over the globe. However, notable differences in annual growth rate of $CO_2$ between MAN and all the comparative sites suggested that its concentration in th MAN area be regulated in more complicated manners than those in the other areas. It is thus suspected that the data collected form MAN area be not effective enough to represent areal distribution characteristics of $CO_2$in the Korean Peninsula.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.6
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• pp.463-474
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• 1997

Metallic elements in dustfall have been known as notable air pollutants directly or indirectly influencing human health and wealth. The first aim of this study was to obtain precise spatial distribution patterns of 5 elements (Pb, Zn, K, Cr, and Al) in dustfall around Suwon area. To predict isometric lines of metal fluxes deposited on unsupervised random sites, the study has applied both spatial statistics as a receptor model and a GIS (geographic information system). Total of 31 sampling sites were selected in the study area (roughly 3 by 3 km grid basis) and dustfall samples were then collected monthly basis by the British deposit gauges from Dec., 1995 to Nov., 1996. The metallic elements in the dustfall were then analyzed by an atomic absorption spectrometer (AAS). On the other hand, a base map overlapped by 7 layers was constructed by using the AutoCAD R13 and ARC/INFO 3.4D. Four different spatial interpolation and expolation techniques such as IDW (inverse distance weighted averaging), TIN (triangulated irregular network), polynomial regression, and kriging technique were examined to compare spatial distribution patterns. Each pattern obtained by each technique was substantally different as varing pollutant types, land of use types, and topological conditions, etc. Thus, our study focused intensively on uncertainty analysis based on a concept of the jackknife and the sum of error distance. It was found that a kriging technique was the best applicalbe in this study area.

• Journal of Korean Elementary Science Education
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• v.17 no.2
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• pp.103-111
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• 1998

The purpose of this study was to investigate the relationship among spatial ability, learning styles, visual-perception- recall abiltiy, and the conceptual construction of the earth and moon's motion. Four paper-and-pencil tests were used to measure students' cognitive variables. Spatial ability was measured by Spatial Visualization Test, visual-perception-recall ability was measured by Rey's Figure which also have used to test visual- perception-recall ability of right-temporal lobes, and VVT were used to investigate students' learning styles. further, the test of concept construction was consisted of 15 items about the earth and moon's motion developed by researcher One hundred and twenty-seven 6th-, one hundred and sixteen 7th-, eighty-seven 9th-grade, ninety-three college students were participated in the investigation of the effects of age and learning style on conceptual construction. In the analysis of students' performances, spatial ability, visual-perception-recall ability, and conceptual achievement showed an increasing pattern with grading. In addition, visual learner's conceptual achievement showed a significantly higher score on conceptual test than verbal learner's(p<0.05). The results of the present study supported tile hypothesis that learning styles would differently influence to learning atmospheric concepts by students'learning styles. This study also indicated to be considered the students' spatial ability in learning atmospheric concepts.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.1
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• pp.51-63
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• 1997

Total suspended particulate matters in the ambient air were analyzed for eight chemical elements (Ca, Co, Cu, Fe, Mn, Pb, Si, and Zn) using an x-ray fluorescence spectrometry (XRF) at the Kyung Hee University - Suwon Campus during 1989 to 1994. To use these data as basis for source identification study, membership of each sample was selected to represent one of the well defined sample groups. The data sets consisting of 83 objects and 8 variables were initially separated into two groups, fine (d$_{p}$<3.3 ${\mu}{\textrm}{m}$) and coarse particle groups (d$_{p}$>3.3 ${\mu}{\textrm}{m}$). A hierarchical clustering method was examined to obtain possible member of homogeneous sample classes for each of the two groups by transforming raw data and by applying various distances. A disjoint principal component analysis was then used to define homogeneous sample classes after deleting outliers. Each of five homogeneous sample classes was determined for the fine and the coarse particle group, respectively. The data were properly classified via an application of logarithmic transformation and Euclidean distance concept. After determining homogeneous classes, correlation coefficients among eight chemical variables within all the homogeneous classes for calculated and meteorological variables (temperature. relative humidity, wind speed, wind direction, and precipitation) were examined as well to intensively interpret environmental factors influencing the characteristics of each class for each group. According to our analysis, we found that each class had its own distinct seasonal pattern that was affected most sensitively by wind direction.ion.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.4
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• pp.347-354
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• 2001

SCR (Selective Catalytic Reduction) process is presently considered as one of the most effective techniques for removing nitric oxides from exhaust gases. In this study, based on the conceptually designed SCR reactor of 500 MW coal fired power plant. a reduced scale (1/20) SCR reactor model was made to analyze the flow pattern in front of catalyst layer according to the guide vane's design factors such as the number, interval, and angle of vanes. The results of the test were compared to those numerical simulation in order to assure the reliability of two methods. On the basis of our study. the critical Reynolds number (2.0$\times$ 10$^{5}$ ) was proposed for ensuring the similarity between the reduced scale model and the prototype of SCR reactor. Optimum design parameters of guide vanes were determined as follows, 4 vanes, the first vane angle of 93$^{\circ}$, and the vane intervals of 0.85 S/n, 1.05 S/n, 1.1 S/n, 1.0S/n, 1.0S/n (S: the distance of duct, n: the number of guide vanes). The excellent agreement between the results of the numerical simulation and the reduced scale model provides the validation of two methods for prediction of flow through SCR reactor.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.195-204
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• 2004

In this study, the concentrations of major reduced sulfur compounds (H$_2$S, $CH_3$SH, DMS, and DMDS) were determined from ambient air in a monitoring station located in the mid-eastern area of Seoul. Measurements of sulfur species were conducted by the combination of on -line air sampling, thermal desorption, and capillary GC/PFPD analysis. A total number of 143 hourly samples were collected in the two time periods set between June and July 2003. The mean concentrations of four sulfur species measured in the whole study period were found on the order: DMS (535$\pm$183) > H$_2$S (47$\pm$10) > DMDS (35$\pm$22) > $CH_3$SH (6.19$\pm$29.4 pptv). The results of this study show that the concentrations of DMS at the study area are generally higher than those reported previously in the oceanic environments, while those of other sulfur species are not easy to compare with due to the lack of data. The H$_2$S concentrations were generally higher during the daytime than the nighttime, whereas those of others generally exhibited a reversed diurnal pattern. The overall results of our study suggest that the distribution of major reduced S compounds should be controlled by diverse processes in the urban area.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.1
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• pp.11-23
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• 2002

The concentrations of aldehydes were measured in downtown area of Buchun and Kwanghwamoon of Seoul from October 1997 to August 1998 using 2-series impingers. The data have been analysed to identify the seasonal pattern of aldehyde sources in metropolitan areas. The measured concentration (in ppbv) of aldehydes were 8.86 $\pm$ 7.28 HCHO (formaldehyde) and 7.79$\pm$7.29 $CH_3$CHO (acetaldehyde) in Buchun, while recording 10.13$\pm$8.58 (HCHO) and 7.64$\pm$6.65 ($CH_3$CHO) in Kwanghwamoon. Their diurnal variation patterns showed significant increase of HCHO and $CH_3$CHO concentration in early afternoon, indicating an increase in secondary sources. Their concentrations however decreased in the nighttime, regardless of seasons. The strength of correlations between certain pairs such as (1) HCHO and CO and (2) $CH_3$CHO and CO were generally high during the winter months (0.64< r < 0.84), suggesting the possibility of similar source processes for HCHO, $CH_3$CHO and CO. On the other hand during the summer months, their correlations are frequently lower than winter months. We suggested that the complexity of source/sink processes during the summer period may reduce the correlations between aldehyde and CO.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.207-215
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• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.

• Asian Journal of Atmospheric Environment
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• v.10 no.3
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• pp.162-167
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• 2016

This study was conducted in an industrial city (Bilaspur) representative of subtropical area in central India. In order to assess the metal deposition on plant, concentrations of six target metals (i.e., Fe, Mn, Pb, Cu, Cd, and Cr) in both plant leaf and dust (deposited on its surface) samples were measured from six different sites. Metal concentrations in dust samples were found on the order of Fe>Mn> Cr>Pb>Cu>Cd. In contrast, the concentration of metals in plant leaves were seen on the order of Fe>Mn>Cr>Cd>Cu>Pb. As such, Cd showed significantly high concentration in leaves relative to their corresponding dust samples. A high accumulation potential for Fe and Cd was seen from Butea monosperma, while Mn and Pb were accumulated noticeably in Pongamia pinnata and Butea monosperma. Likewise, Cr and Cu were enriched in Calotropis procera, Alstonia scholaris, and Butea monosperma. The overall results of our study suggest that the foliar uptake pattern should vary considerably by an interactive role between plant and metal types.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E3
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• pp.95-105
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• 2005

The concentrations of sulfur dioxide ($SO_{2}$) were measured from seven major cities and nine provinces in Korea for the period covering 1998 to 2003. Its concentration data were analyzed to explore the possible influences of spatial and temporal factors on the $SO_{2}$ distribution characteristics. Examination of spatial trends of $SO_{2}$ distribution and behavior indicated several interesting features. Although its annual trends appeared to be affected by the changes in the surrounding environmental conditions (e.g., regulation on the use of S-containing fuels), the seasonal trends indicated a cyclic and systematic pattern that may be characterized as: a gradual decrease in concentrations across winter, spring, fall, and summer. The results showed the generally enhanced mean concentrations of $SO_{2}$ from Ulsan, Busan, and Daegu with 12.8, 10.1, and 8.80 ppb, respectively. On the other hand, notably reduced $SO_{2}$ concentrations were seen from Gwangju and Jeju sites with its mean values of 5.43 and 3.88 ppb, respectively. The overall results of our study indicate that a decrease in $SO_{2}$ concentration levels continued through time, while its spatial distribution appears to be affected most sensitively by such factor as city scale and industrial activities.