• Journal of Korean Society for Atmospheric Environment
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• v.5 no.1
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• pp.11-21
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• 1989

Atmospheric gaseous mercury was automatically measured by a mercury air monitor (Mercury monitor AM-1). The sample air was led to a scrubber and washed with buffer solution, and mercury was trapped with gold coated chromosorb P(AW) was successively eluted by heating the chromosorb and then detected by the cold vapor atomic absorption spectrophotometry. $SO_2, TSP, NO_x, CO, THC$. and some of meteorological factors were also measured simultaneously with mercury. A significant correlation between the concentration of mercury and those of 2,513 measurements, gaseous mercury concentration ranged from 4.73 to 112.8 $ng/m^3$ with an annual mean of 14.7$ng/m^3$ in urban area. At this place there was a clear seasonal variation with a maximuminDecember-January and aminimum in March-June. A secondary maximum existed in August to September. THe seasonal variation was found that the gaseous mercury in ambient air has a tendency to become low in spring and high in winter. Namely, the average of concentration in winter was about two times, 19.2 $ng/m^3$, higher than that in spring. In Seoul mercury levels on some months mainly Septermber-October increase with increasing relative humidity of the atmosphere. In Olympic park air levels were 8.2 (range 4.4-23.7)$ng/m^3$ with an coefficients of variation of 0.34 and in Seoul sports complex those were 7.7 (rnage 4.4-25.5) $ng/m^3$ with an coefficients of variation of 0.38 within the Seoul olympiad holding period of time. A significant diurnal mercury variation occurs both at the measuring sites and in the period of observation.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.97-104
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• 2007

The corelation between the indoor volume and the measured radon concentration has been analyzed by comparing the radon concentration and the indoor volume of apartment rooms in Jeonju City. We also measured the annual exposure dose based on the variation in indoor radon concentration over time. To do this, we took 8 larger rooms and 8 smaller rooms of apartment, respectively, as a sample. The average volume of the larger rooms and that of the smaller rooms were $31.59\;m^3$ and $16.82\;m^3$, respectively. The average radon concentration of the larger rooms and that of the smaller rooms turned out to be $71.73\;Bq/m^3$ and $108.51\;Eq/m^3$, respectively. indicating that indoor volume is in inverse proportion to the radon concentration, i.e., the bigger the ratio of the surface area/volume, the higher the indoor radon concentration. From the measurement of the variation in indoor radon concentration over time fur a single day, the average intraday radon concentration variation was found to be about $46.8\;Bq/m^3$. The highest level of concentration ($114.5\;Bq/m^3$) was measured between 8 and 10 AM and the lowest level of concentration ($67.7\;Bq/m^3$) between 2 and 4 PM. The annual exposure dose turned out to be in the range of 0.3 mSv/yr to 2.16 mSv/yr, showing that the dose in some apartments exceeded 1.3 mSv/yr, the numerical value presented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.28-36
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• 1996

The objects of this study were to investigate emissions of air pollutant the particles as well as the combustibility of the low grade domestic anthracite coal and imported high-calorific bituminous coal in the fluidized bed coal combustor. The production of air pollution from anthracite-bituminous coal blend combustion in a fluidized bed coal combustor was evaluated. The effects of air velocity and anthracite fraction on the reaching time of steady state condition was also evaluated. We used coal samples the domestic low grade anthracite coal with heating value of 2,010 kcal/kg and the imported high grade bituminous coal with heating value of 6,520 kcal/kg. The experimental results are presented as follows. The time of reaching to steady state was affected by the temperature variation. The steady state time was about 120 minute at 0.3 m/s which was the fastest. It has been found that $O_2$ and $CO_2$ concentration were reached steady state at about 100 minute. As the height of fluidized bed becomes higher, the concentration s of $SO_2$ and $NO_x$ mainly increased. The concentration of freeboard was the highest and emission concentration was diminished. Also, as anthracite fraction increased, the emission of $SO_x$ concentration was increased. But, it has been found that the variation of $NO_x$ concentration with anthracite fraction was negligible and the difference of emission concentration according to air flow rates was negligible, too. It has been found that $O_2$ concentration decreased and $CO_2$ concentration increased as the height of fluidized bed increased. As anthracite fraction increased, the mass of elutriation particles increased, and $CO_2$ concentration decreased. Also, as air velocity increased, $O_2$ concentration decreased and $CO_2$ concentration increased. Regardless-of anthracite fraction and flow rate, the combustible weight percentage in elutriation particles were high in the case of fine particles.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.3
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• pp.253-262
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• 1995

A study has been performed on the characteristics of rural and urban surface ozone concentration for the period of March 1992 to February 1993. The monitoring station of rural ozone is located at Kosan, Cheju and other urban monitoring stations are located at Seoul, Pusan and Kwangju. Rural's and urban's ozone data exhibit a distinct features in many ways. First, annual mean of rural ozone concentration os very high(42 ppbv) but urban's are very low(10 .sim.15 ppbv). Second, rural ozone data shows a seasonal variation with it's maximum in spring, and minimum in summer, but urban's show a seasonal variation with it's maximum in spring, and minimum in winter. Third, diurnal variation of rural data is very small but that of urban's are very large. Fourth, urban's data are extremely low(< 3 ppbv) and have no seasonal variations.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.7-14
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• 1996

Two experiments were conducted to evaluate breathing zone air quality in Taegu, using automatic analyzers for four air quality standards($SO_2$, $NO_2$, CO, and $O_3$). First, air target compounds were measured for 8 to 12 hours in each of two commercial areas and five residential areas. Second, air target compounds were hourly measured for 24 hours in each of two commercial areas, two residential areas, and an industrial complex area. Based on the first experiment the breathing zone air was more polluted in the commercial area as compared to the residential area, while the second experiment showed that the breathing zone air was polluted rather in the residential are3 as compared to the commercial area. The second experiment also indicated that there was some variation of breathing zone air concentration with time and measuring sites. Diurnal variation of breathing zone air concentrations was consistent with previous studies which measured at building height. The highest breathing zone air concentration was shown in Seongseo industrial complex area. An unusual finding of this study was that $SO_2$ concentration in the breathing zone air of Bisandong, a typical residential area of Taegu, was higher than that of other residential areas, even higher than that of Seongseo industrial complex area.

• Korean Journal of Veterinary Research
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• v.36 no.3
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• pp.731-741
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• 1996

ELISA kit for cortisol was developed and then evaluated. Polyclonal antihydrocortisone-3-(o-carboxymethyl)oxime BSA rabbit serum was used to coat the 96-well microplates. The minimum detection limit of the kit was 250pg of cortisol per milliliter. The within-run variation and the day to day variation of the ELISA system were 2.0 and 5.9 at maximum, respectively. The kit was used to determine whether salivary cortisol concentration could replace blood cortisol concentration in dexamathasone suppression test of dogs. Changes of cortisol concentration were measured in serum or saliva after intravenous administration of 0.01mg of dexamethasone per kilogram of body weight. Blood alone, saliva alone or both were collected at 0, 30, 60, 120, 240, and 360 minutes after injection of dexamethasone. The change in blood cortisol concentration was found to be suitable in dexamathasone suppression test of dogs, but the change in salivary cortisol concentration was not. The kit was also used to determine whether salivary cortisol concentration could be a stress index as well as blood cortisol concentration in dogs. Two types of trial were performed to estimate the stress either by blood or salivary cortisol concentration. The first trial was stress experiment by intravenous injection of 0.2IU of PZI-insulin per kilogram body weight. Either blood alone or saliva alone was collected at 0, 30, 60, and 90 minutes after insulin administration. Both blood and salivary cortisol concentration were found to be suitable index in estimating stress from hypoglycemia by injection of insulin. The second trial was stress experiment by electrical irritation. The dogs were irritated with anti-bark device for 10 seconds. Blood was collected before and at 2 and 5 minutes after electrical irritation. Saliva was collected before and at 3 and 6 minutes after electrical irritation. The blood cortisol concentration, but not the salivary cortisol concentration was found to be suitable index in estimating stress from electrical irritation. Cushing syndrome in a dog was also successfully diagnosed with this kit.

• Journal of Environmental Science International
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• v.3 no.3
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• pp.241-252
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• 1994

Meteorological parameters In the atmospheric boundary layer and the vertical and horizontal dispersion parameters were determined by analyzing the data obtained by the special upper-air observations of one clear day for each season from October 1991 to August 1992. The concentration of the aklospheric pollutants over Taegu was analyzed by using the application of the Gaussian diffusion model. In the diurnal variation of diffusion of atmospheric pollutants, vertical diffusion due to turbulence is active in daytime while horizontal diffusion due to wind is active in nighttime. The mean concentration of pollutants in the side of downwind is higher during the daytime than the nighttime. Thus, the height of the mixed-layer at the nighttime considered as the most important parameter of the mean concentration of pollutants. In the seasonal variation of diffusion of atmospheric pollutants, vertical diffusion due to strong solar radiation is active in summer case day, and horizontal diffusion due to strong wind is active in winter case day. In winter case day, the mean concentration of pollutants in the side of downwind is maximum in the daytime. However, in summer case day, that is maximum in the nighttime.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.143-152
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• 2008

This study investigates the variation and spatial distribution of nitrogen dioxide($NO_2$) concentrations measured with passive diffusive samplers at 40 curbside points in Daejeon. Average $NO_2$ concentration was $39.8{\pm}18.0\;ppb$ (n=1,127) and the significant difference in concentrations by regional groups (Dong-gu, Jung-gu, Seo-gu, Daedeok-gu, Yuseong-gu) was not observed. The frequency distribution of $NO_2$ concentration was found to be a normal distribution with the high frequency in the concentration range of 30 to 40 ppb (20 to 25%). Average $NO_2$ concentration measured during the rainy periods was lower than that measured during the non-rainy periods and the decrease of concentration by rainfall was about 16% (7 ppb). The variation of $NO_2$ concentrations measured by passive diffusive samplers during the sampling period was similar to that continuously measured at the air quality monitoring station.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.5
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• pp.668-676
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• 2018

This study has developed a technique to divide the aerosol optical depth of the entire aerosol (${\tau}_{total}$) into the dust optical depth (${\tau}_D$) and the pollution particle optical depth (${\tau}_P$) using the AERONET sun/sky radiometer data provided in Version 3. This method was applied to the analysis of AERONET data observed from 2006 to 2016 in Beijing, China, Seoul and Gosan, Korea and Osaka, Japan and the aerosol optical depth trends of different types of atmospheric aerosols in Northeast Asia were analyzed. The annual variation of ${\tau}_{total}$ showed a tendency to decrease except for Seoul where observation data were limited. However, ${\tau}_D$ tended to decrease when ${\tau}_{total}$ were separated as ${\tau}_D$ and ${\tau}_P$, but ${\tau}_P$ tended to increase except for Osaka. This is because the concentration of airborne aerosols, represented by Asian dust in Northeast Asia, is decreased in both mass concentration and optical concentration. However, even though the mass concentration of pollution particles generated by human activity tends to decrease, Which means that the optical concentration represented as aerosol optical depth is increasing in Northeast Asia.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.451-461
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• 2006

Laboratory scale experiments were conducted to study the conversion of sludge from conventional activated sludge to nitrogen-phosphorus removal sludge using two types of sequencing batch reactor (SBR) systems, a conventional SBR and sequencing batch biofilm reactor (SBBR). The nitrogen and phosphorus removal characteristics were similar between SBR and SBBR and the removal efficiencies were very low when the influent TOC concentrations were low. The nitrogen and phosphorus removal efficiencies in SBR were 96% and 77.5%, respectively, which were higher than those in SBBR (88% and 42.5%) at the high influent TOC concentration. In SBBR, the simultaneous nitrification-denitrification was occurred because of the biofilm process. The variations of pH, DO concentration and ORP were changed as the variation of influent TOC concentration both in SBR and SBBR and their periodical characteristics were cleary shown at the high influent TOC concentration. Especially, the pH, DO concentration and ORP inflections, were cleary occurred in SBR compared with SBBR.