• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.38-55
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• 2018

Hourly measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), and water-soluble ionic species were made at the air quality intensive monitoring stations in Baengryeongdo (BR) and Seoul (SL) during the winter (December 01~31, 2013) and summer (July 10~23, 2014) periods, to investigate the increase of $PM_{2.5}$ and secondary ionic species and the reasons leading to their increase during the two seasons. During winter, $PM_{2.5}$ and its major chemical species concentrations were higher at SL than at BR. Contribution of organic mass to $PM_{2.5}$ was approximately 1.7 times higher at BR than at SL, but the $NO_3{^-}$ contribution was two times higher at SL. Total concentration of secondary ionic species ($SO{_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$) at BR and SL sites accounted for 29.1 and 40.1% of $PM_{2.5}$, respectively. However, during summer, no significant difference in chemical composition of $PM_{2.5}$ was found between the two sites with the exception of $SO{_4}^{2-}$. Total concentration of the secondary ionic species constituted on average 43.9% of $PM_{2.5}$ at BR and 53.0% at SL. A noticeable difference in chemical composition between the two sites during summer was attributed to $SO{_4}^{2-}$, with approximately twofold concentration and 10% higher contribution in SL. Low wind speed and high relative humidity were important factors in secondary formation of water-soluble ionic species during winter at SL, resulting in $PM_{2.5}$ increase. While the secondary formation during summer was attributed to strong photochemical processes in daytime and high relative humidity in nighttime hours. The increase of $PM_{2.5}$ and its secondary ionic species during the winter haze pollution period at SL was mainly caused either by long-range transport (LTP) from the eastern Chinese regions, or by local pollution. However, the increased $SO{_4}^{2-}$ and $NO_3{^-}$ during summer at SL were mainly caused by LTP, photochemical processes in daytime hours, and heterogeneous processes in nighttime hours.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.183-192
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• 1998

The long-term observation of temperature in the coastal waters adjacent to the Wolsung Nuclear Power Plant has been carried out from November 10, 1996 to August 22, 1997, for approximately 280 days using a real-time temperature measurement buoy system. The sea-surface temperature was measured at every 10 minute using 10 buoys. The vertical structure of temperature was investigated near the outlet of the plant with two thermistor chains equipped with 10 sensors at 1 m interval The monthly averaged temperature was the lowest with spatial average of $12.8^{\circ}C$ in February and was the highest in August with spatial average of $19.6^{\circ}C$. The extremely low temperature was frequently observed between June and August, which seems to be the consequence of the intrusion of cold water near the southeastern coast of Korea. Distributions of the daily and hourly averaged temperature show that the highest temperature always occurred near the outlet of the plant and the warm-water patch moved along the north-south direction with the semidiurnal period. The semidiurnal fluctuation of temperature was also observed near the surface of the vertical profiles. The spectral analysis of temperature between February and April 1997 shows that the semidiurnal components prevailed near the outlet. It is likely that the semidiurnal components were due to the prevailing semidiurnal tide in this region. In August 1997, the diurnal components were dominant at the surface water of all stations except Station 12, which suggests that the warm water from the outlet of the plant has less effects in summer on the surrounding waters than the strong solar radiation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.1-16
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• 2007

The use of information on natural resources is indispensable to most agricultural activities to avoid disasters, to improve input efficiency, and to increase lam income. Most information is prepared and managed at a spatial scale called the "Hydrologic Unit" (HU), which means watershed or small river basin, because virtually every environmental problem can be handled best within a single HU. South Korea consists of 840 such watersheds and, while other watershed-specific information is routinely managed by government organizations, there are none responsible for agricultural weather and climate. A joint research team of Kyung Hee University and the Agriculture, forestry and Fisheries Information Service has begun a 4-year project funded by the Ministry of Agriculture and forestry to establish a watershed-specific agricultural weather information service based on "high definition" digital climate maps (HD-DCMs) utilizing the state of the art geospatial climatological technology. For example, a daily minimum temperature model simulating the thermodynamic nature of cold air with the aid of raster GIS and microwave temperature profiling will quantify effects of cold air drainage on local temperature. By using these techniques and 30-year (1971-2000) synoptic observations, gridded climate data including temperature, solar irradiance, and precipitation will be prepared for each watershed at a 30m spacing. Together with the climatological normals, there will be 3-hourly near-real time meterological mapping using the Korea Meteorological Administration's digital forecasting products which are prepared at a 5 km by 5 km resolution. Resulting HD-DCM database and operational technology will be transferred to local governments, and they will be responsible for routine operations and applications in their region. This paper describes the project in detail and demonstrates some of the interim results.

• Journal of Chest Surgery
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• v.32 no.1
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• pp.43-48
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• 1999

Background: Although treatment of spontaneous pneumothorax by video-assisted thoracic surgery(VATS) has generally shown better clinical results than conventional thoracotomy, treatment of spontaneous pneumothorax by midaxillary thoracotomy(MAXT) has also shown good clinical results. The author studied to compare the clinical results of MAXT group I and VATS group II. Material and Method : Group I included 30 midaxillary thoracotomy among 83 operative cases of spontaneous pneumothorax from Jan. 1992 to Dec. 1993. Group II included 30 VATS among 101 operative cases of pneumothorax from Jan. 1994 to Aug. 1995. The author selected the 30 patients, age 18 to 25 years, with recurrent spontaneous pneumothorax in each group. The author analyzed the operative indication, gender, operating time, amounts of the used staplers, tube drainage, total amounts of analgesics used during postoperative 24hr, tube stay time, postoperative complications and mortality. Result: The follow-up periods of both procedures were from 6 to 43 months. The operating time from start of skin incision to end of skin closure was 84.79${\pm}$21.70(from 40 to 150) minutes in MAXT group I and 108.8${\pm}$42.02(from 58 to 120) minutes in VATS group II(P<0.001). The numbers of the used staples useo was 1.31${\pm}$0.6(from 0 to 3) in group I and 3.41${\pm}$2.37(from 0 to 11) in group II. The amounts of postoperative 24hour tube drainage were 220.76${\pm}$106.73(from 65 to 400) ml in group I and 260.63${\pm}$233.18(from 70 to 320) in group II(P>0.05). The amounts of postoperative 24 hourly used analgesics(Tarasyn ) was 1.38${\pm}$1.32(from 0 to 5) amples in group I and 0.72${\pm}$1.02(from 0 to 4) amples in group II (P<0.05). The postoperative tube stay is 5.45${\pm}$30.9 (from 3 to 7) days in group I and 4.75${\pm}$3.1(9 from 2 to 14) days in group II(P>0.05). The number of complications after operations was 2 cases of prolonged air leakage in group I, and in group II. (P is not significant). The number of recurrence after the operation was one in group I and also one in group II(P is not significant). In conclusion, there were no statistical differences in the postoperative 24 hour chest tube drainage, days of postoperative tube stay, postoperative complications and recurrence in the analysis between group I and group II. Conclusion: The author found that group II of VATS between 18 years and 25 years of age in recurrent spontaneous pneumothorax, statistically, requires longer operative time, more number of autosuture staples and less postoperative analgesic dosage than the midaxillary thoracotomy group I.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.199-205
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• 2001

This study was conducted to figure out temperature profiles of a partially developed paddy rice canopy, which are necessary to run plant disease forecasting models. Air temperature over and within the developing rice canopy was monitored from one month after transplanting (June 29) to just before heading (August 24) in 1999 and 2001. During the study period, the temporal march of the within-canopy profile was analyzed and an empirical formula was developed for simulating the profile. A partially developed rice canopy temperature seemed to be controlled mainly by the ambient temperature above the canopy and the water temperature beneath the canopy, and to some extent by the solar altitude, resulting in alternating isothermal and inversion structures. On sunny days, air temperature at the height of maximum leafages was increased at the same rate as the ambient temperature above the canopy after sunrise. Below the height, the temperature increase was delayed until the solar noon. Air temperature near the water surface varied much less than those of the outer- and the upper-canopy, which kept increasing by the time of daily maximum temperature observed at the nearby synoptic station. After sunset, cooling rate is much less at the lower canopy, resulting in an isothermal profile at around the midnight. A fairly consistent drop in temperature at rice paddies compared with the nearby synoptic weather stations across geographic areas and time of day was found. According to this result, a cooling by 0.6 to 1.2$^{\circ}C$ is expected over paddy rice fields compared with the officially reported temperature during the summer months. An empirical equation for simulating the temperature profile was formulated from the field observations. Given the temperature estimates at 150 cm above the canopy and the maximum deviation at the lowest layer, air temperature at any height within the canopy can be predicted by this equation. As an application, temperature surfaces at several heights within rice fields were produced over the southwestern plains in Korea at a 1 km by 1km grid spacing, where rice paddies were identified by a satellite image analysis. The outer canopy temperature was prepared by a lapse rate corrected spatial interpolation of the synoptic temperature observations combined with the hourly cooling rate over the rice paddies.

• Korean Journal of Environmental Agriculture
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• v.10 no.1
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• pp.33-49
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• 1991

In order to disclose the contamination of the Mushim-Cheon by pollutants and to establish the countermeasures, the water samples collected in November of 1989(lst sample), February(2nd), May(3rd) and August of 1990(4th) were analyzed to obtain the following results : 1. The water temperatures of the seasonal samples ranged from 8.6 to 16.2, 8.3 to 25.2, 18 to 26, and 24 to 32$^{\circ}C$, in the 1st, 2nd , 3rd, and 4th samples, respectively. 2. The pHs of all the samples ranged from 6.5 to 8.5. 3. In the 3rd sample, especially, DO was observed to fall down to 0.8 ppm at the downstream of St 13, which is not allowed even for agricultural use. 4. The BOD and COD values in sewers were much higher than those in the main stream, and especially the values of St 14-A reached 107-608 and 176-635 ppm, respectively, which far exceeded the limit of 40 ppm, the allowed value for the discharges from the disposal facilities. The SS value of St 14A ranged from 142 to 1, 900 ppm, which far exceeded the limit of 70 ppm, the allowed value for the discharges from the disposal facilities. 5. It turned out that the water quality of the Mushim-Cheon flowing through Cheong Ju was more worsened at sewers than the main stream, and at the downstream than the upstream of the surveyed area. Accordingly, the sewage disposal plant and the expansion of the disposal facilities are urgently needed.

• Journal of Food Hygiene and Safety
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• v.32 no.4
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• pp.321-328
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• 2017

Fusarium graminearum is a mycotoxigenic plant pathogen, which could remain in harvested barley grains and produces mycotoxins at preferable conditions during storage. To elucidate the factors affecting contamination of Fusarium and Fusariotoxin in hulled barley during storage, three hulled barley grain samples were collected from Jeolla province. Moisture content of each sample was adjusted to 14% and 20%, respectively, then stored in two warehouses where temperature was controlled differently: one controlled below $12^{\circ}C$, and the other with no control. While monitoring temperature and relative humidity of warehouses hourly, grain moisture content, Fusarium occurrence, and mycotoxin level was analyzed at 1, 3, 6, and 12 month after storage. The average monthly temperature and relative humidity ranged $3{\sim}29^{\circ}C$, and 58~70% in warehouse without temperature control, whereas $3{\sim}13^{\circ}C$ and 62~74% in warehouse controlled below $12^{\circ}C$. Grain moisture content of the samples decreased in both warehouses except 14% samples which increased in the warehouse with temperature control. Fusarium frequency of the contaminated grains decreased continuously in the warehouse without temperature control. But in the warehouse below $12^{\circ}C$, Fusarium decreasing rate was slower because of high grain moisture content. In most samples, nivalenol was detected more in the warehouse without temperature control after 12 month but there was little difference after 1, 3, and 6 month. Therefore, it will be efficient to store hulled barley in the warehouse controlled below $12^{\circ}C$ to reduce Fusarium contamination when the barley is not dried properly. In addition, when storage period exceeds 12 month, it is recommended to store hulled barley in a warehouse controlled below $12^{\circ}C$ to reduce nivalenol contamination.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.268-276
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• 2007

Urban atmosphere may play as a harbinger for the future climate change with respect to temperature and $CO_2$ concentration. The Seoul metropolitan area is unique in rapid urbanization and industrialization during the last several decades, providing a natural $CO_2$ dome with increased temperature. This study was carried out to evaluate the feasibility of using the urban-rural environmental gradient in replacement of the IPCC mid-term scenario (after 30-50 years). For this, we measured atmospheric $CO_2$ concentration and air temperature at three sites with different degree of urbanization (Seoul, Suwon, and Icheon). Results from 11-month measurement can be summarized as follows: (1) The annual mean $CO_2$ concentration across 3 sites was in the order of Seoul (439 ppm) > Suwon (419 ppm) > Icheon (416 ppm), showing a substantial urban-rural environmental gradient. (2) The diurnal fluctuation in $CO_2$ concentration was greater in summer than in winter, showing the effect of photosynthesis on local $CO_2$ concentration. (3) The daily maximum $CO_2$ concentration was observed at 0500 LST in spring and summer, 0800 LST in autumn, and 0900 LST in winter, showing the sunrise-time dependence. (4) The observed hourly maximum $CO_2$ concentration averaged for the whole period was 446 ppm in Seoul at 0700 LST, while the minimum was 407 ppm in Suwon at 1500 LST. (5) Compared with the background atmospheric concentration of $CO_2$ in Anmyeon-do (377.4 ppm annual mean), $CO_2$ concentration of the study sites was higher by 14% in Seoul, by 10% in Suwon, and by 9% in Icheon. The observed $CO_2$ concentration in Seoul reached already 98% of the 2030-2040 projection (450 ppm) and 80% of the 2040-2050 projection (550 ppm) under the IPCC BAU scenario, showing a feasibility of using the $CO_2$ dome of Seoul as a natural experimental setting for the mid-term climate change impact assessment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.61-69
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• 2003

Surface energy and $CO_2$ fluxes have been measured over a farmland in Haenam, Korea since July 2002. Eddy covariance technique, which is the only direct flux measurement method, was employed to quantitatively understand the interaction between the farmland ecosystem and the atmospheric boundary layer. Maintenance of eddy covariance system was the main concern during the early stage of measurement to minimize gaps and uncertainties in the dataset. Half-hourly averaged $CO_2$ concentration showed distinct diurnal and seasonal variations, which were closely related to changes in net ecosystem exchange (NEE) of $CO_2$. Daytime maximum $CO_2$ uptake was about -1.0 mg $CO_2$ m$^{-2}$ s$^{-1}$ in August whereas nighttime $CO_2$ release was up to 0.3 mg $CO_2$ m$^{-2}$ s$^{-1}$ during the summer. Both daytime $CO_2$ uptake and nighttime release decreased gradually with season. During the winter season, NEE was from near zero to 0.05 mg $CO_2$ m$^{-2}$ s$^{-1}$ . FK site was a moderate sink of atmospheric $CO_2$ until September with daily NEE of 22 g $CO_2$ m$^{-2}$ d$^{-1}$ . In October, it became a weak source of $CO_2$ with an emission rate of 2 g $CO_2$ m$^{-2}$ d$^{-1}$ . Long-term flux measurements will continue at FK site to further investigate inter-annual variability in NEE. to better understand these exchange mechanism and in-depth analysis, process-level field experiments and intensive short-term intercomparisons are also expected to be followed.

• Tuberculosis and Respiratory Diseases
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• v.55 no.6
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• pp.570-578
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• 2003

Background : Ambient particles during Asian dust events are usually sized less than $10{\mu}m$, known to be associated with the adverse effects on the general populations. But, there has been no considerable evidence linking these particles to the adverse effects on airways. The objectives of this study was to investigate the possible adverse effects of Asian dust events on respiratory function and symptoms in subjects with bronchial asthma. Patients and Methods : From march to June 2002, Asthmatic patients who were diagnosed with bronchial challenge test or bronchodilator response were enrolled. We divided them into three groups; mild, moderate, and severe, according to the severity. Subjects with other organ insufficiency such as heart, kidney, liver, and malignancy were excluded. All patients completed twice daily diaries and recorded peak flow rate, respiratory symptom, and daily activity. Daily and hourly mean pollutant levels of particulate matter < $10{\mu}m$ in diameter($PM_{10}$), nitrogen dioxide($NO_2$), sulphur dioxide($SO_2$), ozone($O_3$) and carbon monoxide(CO) were measured at the 10 different monitoring sites. Results : Dust events occured 14 times during the study period. Daily averages of 4 air pollutant were measured with an increased level of $PM_{10}$, decreased level of $NO_2$ and $SO_2$, and no change in CO during dust days compared to those during control days. An increase in $PM_{10}$ concentration was associated with an increase of subjects with PEF variability of >20% (p<0.05), night time symptom(p<0.05), and a decrease in mean PEF (p<0.05), which were calculated by the longitudinal data analysis. Otherwise, there was no association between $PM_{10}$ level and bronchodialtor inhaler, and daytime respiratory symptoms. Conclusion : This study shows evidence that ambient air pollution, especially $PM_{10}$, during Asian dust events, could be one of the many aggravating factors at least in patients with airway diseases. This data can be used as a primary source to set up a new policy on air environmental control and to evaluate the safety of air pollution index. We also expect that this research will help identify precise components of dust, which are more linked to the adverse effects.