• Journal of Korean Society for Atmospheric Environment
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• v.4 no.2
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• pp.67-71
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• 1988

To estimate the probability of short term concentration of air pollution using long term arithmetic average concentration, the procedure was developed and added to Texas Climatological Model version 2. In the procedure, such statistical characteristics that frequency distribution of short term concentration may be approximated by a lognormal distribution, were applied. This procedure is capable of estimating not only highest concentration for a variety of averaging times but also concentrations for arbitrary occurrence frequency. Evaluation of the procedure with the results of short term concentrations calculated by Texas Episodic Model version 8 using the meteorological data and emission data in Seoul shows that the procedure estimates concentrations fairly well for wide range of percentiles.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.179-189
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• 2003

The concentration of gaseous elemental mercury (Hg) was measured concurrently with relevant environmental parameters from Yang-Jae monitoring station in Seoul during Sept. 1997 to June 2002. Although data collection was disrupted for certain periods, the grand mean concentration of Hg for this five year period was found at 5.32 $\pm$ 3.53 ng m$^{-3}$ (N = 27,170). Because of short resolution of data acquisition, we were able to examine the temporal variability of Hg at varying time scale. The diurnal variability of Hg, when investigated for each of those five years, indicated consistently the dominance of nighttime over daytime. If examined at seasonal scale, Hg level was systematically higher during winter/spring than summer/fall period. The results of this short-term variability were best explained by the combined effects of such factors as meteorological conditions (formation of inversion layer and seasonal changes) and anthropogenic source processes. However, examination of long-term variation Pattern was much more complicated to explain. Thus, extension of our study is needed to diagnose the future direction in long-term trend of Hg behavior.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.2
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• pp.177-189
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• 2010

In order to incorporate correctly the large or local scale circulation in an atmospheric model, a nudging term is introduced into the equation of motion. The MM5 model was used to assess the meteorological values differences in each case, during ozone episode days in Gwangyang bay. The main objective of this study is to investigate the effect of horizontal and vertical flow fields according to the surface and vertical observation data assimilation by upper wind conditions. Therefore, we carried out several numerical experiments with various parameterization methods for nudging coefficient considering the upper wind conditions (synoptic or asynoptic condition). Nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, therefore appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. Obviously, under the weak synoptic wind, there was apparent advantage associated with nudging coefficient by the regional difference. The accuracy for the prediction of the meteorological values has been improved by applying the appropriate PBL (Planetary Boundary Layer) limitation of circulation.

• Asian Journal of Atmospheric Environment
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• v.9 no.1
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• pp.48-56
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• 2015

The trajectory analysis of boundary layer ozone data at four regional sites in the East Asian outflow regions in Japan was carried out together with boundary layer ozone data observed at Mt. Tai and Mt. Huang in the source region of central eastern China during the monsoon onset in May-June 2003 and 2004. At all sites, the influences of anthropogenic emissions from East Asia have been found. During May and June 2004, the evidences of direct pollution transport from central eastern China to Hedo, an outflow site in Okinawa Island were observed. Ozone mixing ratios associated with air masses from central eastern China averaged 45 ppb while those associated with clean air masses from the Pacific were only 14 ppb, which resulted in averaged 31 ppb increase of ozone mixing ratios during the pollution episodes from central eastern China at Cape Hedo. Using transport time analysis and averaging all ozone episodes transported from central eastern China, the ozone dilution rate of 5.4 ppb per day was roughly estimated during air masses transported from source to outflow regions at Hedo. In the regions nearby Japanese mainland, however ozone increases by long-range transports were more related to both domestic and East Asian sources as a whole.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.200-206
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• 1993

Since November 1990, observations of carbon monoxide(CO) levels have been carried out at Tat-ahn Peninsula(TAP) in Korea. Analysis on atmospheric data, obtained in the period from November 1990 to February 1992, is carried out and the results are included in this study. It is observed that variations of monthly average level on CO are in the range of 141.61-516.06ppb(amplitude 374.45 ppb). An average level in 1991 is 308.18 ppb. CO observed at TAP has a larger seasonal variation. One of reasons appears that CO of TAP is strongly influenced by local sources and westerly airflows. When this gas of TAP is compared with data observed at Korea National University of Education(KNU) and in Seoul, we learn that CO values of KNU are higher(in average 2.15 times) than those of TAP; CO value observed in Seoul are 7 times higher than those of TAP. We interprete that air samples taken both at KNU and in Seoul are influenced strongly by local sources than those at TAP. According to analysis of trajectories and air flows, the CO value is higher with NW airflows than the value with SW airflows.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.3
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• pp.277-288
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• 2001

Continuous atmospheric CO$_2$measurements measured during the 1 year(1998.8∼1999.8) at Korea Global Atmosphere Watch Observatory (KGAWO) in Anmyeon-do are analyzed by the selecting method which is recommended by WDCGG to get background CO$_2$. This method can reject data based on two criteria: the instability of CO$_2$ concentration within 1 hour from hourly standard deviation (hourly variability$\leq$ 0.6 ppm first selection) and the large changes in the CO$_2$ concentration from one hour to the nex(∼$\leq$0.3 ppm, second selection). We could obtain hourly background CO$_2$ of 37% in first selection and 20% in second selection during the l year. That are a little less than those of Ryori station in Japan. especially, the cases of background CO$_2$ which is selected were few during the summer. That is caused by affection of vegetation and anthropogenic source. After the selecting methods are applied, the cases which is selected for easterly wind decrease remarkably according to the analysis of wind direction about continuous CO$_2$ .That was affected by anthropogenic source from the east area.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.6
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• pp.632-643
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• 2012

Analysis of wind resources in Planetary Boundary Layer (PBL) using long term observation of tall tower located near coast line of the Korean Peninsula were carried out. The data observed at Pohang, Gunsan and Jinhae are wind, temperature and relative humidity with 10 minute interval for one year from 1 October 2010. Vertical turbulence intensity and its deviation at Pohang site is smaller than those of other sites, and momentum flux estimated at 6 vertical layers tend to show small difference in Pohang site in comparison with other sites. The change of friction velocity with atmospheric stability in Pohang is also not so great. These analysis indicate the mechanical forcing due to geographical element of upwind side is more predominant than thermal forcing. On the other hand, wind resources at Gunsan and Jinhae are mainly controlled by thermal forcing.

• Asian Journal of Atmospheric Environment
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• v.6 no.3
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• pp.169-191
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• 2012

This review paper describes the ambient air PAH concentrations in different developing Asian countries, including China, Afghanistan, India, Malaysia, Turkey, Vietnam, Sri Lanka, Thailand and Cambodia. In this study, more than 75 research papers published in the English literature were reviewed with respect to the seasonal and locational concentrations of PAHs in each of 9 different Asian countries. This study compared, discussed and tabulated the PAH concentrations in developing Asian countries over a one decade (2000-2011) period. The PAH concentrations measured in developing countries highlights the necessity to improve the air quality in those countries. Compared to the developed nations in Asia, developing countries are almost one decade away from implementing environmental policies, such as Euro standards. This review discusses the reasons for the high PAH concentrations in developing nations particularly in China and India. Based on the literature available, some suggestions are made to reduce the concentrations of PAHs in the ambient air of developing nations. The total data obtained from the literature survey is tabulated and presented as supplementary information at the end of the manuscript.

• Asian Journal of Atmospheric Environment
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• v.2 no.1
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• pp.47-53
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• 2008

In this study, we analyzed how ozone pollution could be differently measured and how these different measures varied year to year and across the ten most populated cities in the United States, from 1980 to 2000. Although peak values of ozone concentration have been significantly reduced in most polluted U.S. cities for the last 20 years, the annual average values of ozone concentration have not been lowered as much as peak values. Ozone concentration data for each city shows a unique pattern of distribution, central tendency, and also there is a wide variation among different ozone measures. Two different cities with the same annual mean concentration of ozone can experience very different distributions of ozone concentration within a year. Ozone measures also show a wide margin of variability as they are estimated from different ozone monitoring sites within each city. Ozone pollution statistics can be largely varied depending on the choice of measures, monitoring sites, and averaging time period. EPA's new ozone standard of 0.08 ppm averaged over an eight-hour appears to be more stringent than the current maximum ozone standard of 0.12 ppm averaged over one hour.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.26-36
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• 2014

The uncertainty assessment is important to improve the reliability of emission inventory data. The DARS (Data Attribute Rating System) have recommended as the uncertainty assessment technic of emission inventory by U.S. EPA (Environmental Protection Agency) EIIP (Emission Inventory Improvement Program). The DARS score is based on the perceived quality of the emission factor and activity data. Scores are assigned to four attributes; measurement/method, source specificity, spatial congruity and temporal congruity. The resulting emission factor and activity rate scores are combined to arrive at an overall confidence rating for the inventory. So DARS is believed to be a useful tool and may provide more information about inventories than the usual qualitative grading procedures (e.g. A through E). In this study, the uncertainty assessment for 2009 CAPSS (Clean Air Policy Support System) emission inventory is conducted by DARS. According to the result of this uncertainty assessment, the uncertainty for fugitive dust emission data is higher than other sources, the uncertainty of emission factor for surface coating is the highest value, and the uncertainty of activity data for motor cycle is the highest value. Also it is analysed that the improvement of uncertainty for activity data is as much important as the improvement for emission factor to upgrade the reliability of CAPSS emission inventory.