• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.485-494
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• 2018

This study aims to identify the characteristics of oxidation and chemical composition of PM in winter season, 2017 at Incheon area. The mean concentration of air pollutants were $46{\pm}22{\mu}g/m^3-PM_{10}$, $29{\pm}18{\mu}g/m^3/-PM_{2.5}$, $5{\pm}3ppb-SO_2$, $0.56{\pm}0.24ppm-CO$, $21{\pm}13ppb-O_3$ and $28{\pm}17ppb-NO_2$, respectively. The dominant ion of the $PM_{1.0}$ chemical component were organic with $3.2{\mu}g/m^3$ and nitrate with $1.9{\mu}g/m^3$. The day and night variation of the $PM_{1.0}$ chemical components was higher in nighttime than those of daytime. The averaged nitrate oxidation rate (SOR) was 0.06 and sulfate oxidation rate was 0.11 during the field campaign. In the high mass loading period, nitrate oxidation rate (NOR) was up to 0.6 and also the nitrate in $PM_{1.0}$ was increased. The averaged ratio of $NO_x/SO_2$ was 8.7 and nitrate/sulfate was 3.1, respectively. In this results, the nitrate component in $PM_{1.0}$ was influenced by NOx from the stationary source as power plant and the mobile source around the measurement site.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.276-285
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• 1998

The aboveground biomass and nutrient content (N, P, K, Ca and Mg) of Pinus koraiensis S. et Z., aged 9, 22, 34, 46, 66 years, were measured in the Experiment Forest of Kangwon National University of Kangwondo province. The site index of the stands ranged from 13.5 to 14.2. Allometric equations (logY=alogX+b, where Y, X is ovendry mass and DBH, respectively) relating dry weights of stem, branches and needles to diameter at breast height (DBH) were developed to estimate aboveground tree biomass. Total above ground tree biomass increased with stand age from $21.8t\;ha^{-1}$ in the 9-year-old stand to $130t\;ha^{-1}$ in the 66-Year-old stand. Aboveground biomass was allocated as follows : stem> branch > foliage, except for the 9-year-old stand which had a greater proportion of foliage biomass than branch biomass. As stand age increased, an increasing proportion of annual biomass increment was allocated to stems. The aboveground biomass of shrubs and herbs ranged from 0.4 to $3.9t\;ha^{-1}$ and from 0.05 to $0.6t\;ha^{-1}$, respectively. No relationship was found between aboveground understory biomass and stand age. The mass of woody debris and forest floor varied between 0.59 to $1.54t\;ha^{-1}$ and 6.0 to $21.63t\;ha^{-1}$, respectively. Nutrient accumulation in aboveground tree biomass increased with stand age and was in the order of N > Ca > K > P > Mg. Average rates of nutrients accumulation in biomass were greatest in the early stages of stand development, and less marked as stand aged. The nutrient concentrations in different tree components decreased in the order of needle > branch > stem. There were no detectable trends in nutrient content of the forest floor and mineral soils with stand age. Understory vegetation contributed little to the nutrient pool of these Korean pine ecosystems. Mineral soil contained the Breast proportion of nutrient capital of the various ecosystem compartments.

• Journal of the Korean Society of School Health
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• v.23 no.1
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• pp.29-40
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• 2010

Purpose: The purposes of this study were: (a) to assess indoor air quality such as $PM_{10}$, $CO_2$ concentrations in child daycare centers, (b) to compare the levels with each standard, and (c) to identify teachers' awareness of indoor air quality in child care centers. Methods: Data were obtained from seventeen child daycare centers and ninety-eight teachers in a district of Seoul, from April 3 to May 12, 2009. Collected data were analyzed by SAS 8.2, and descriptive statistics, $x^2$ test, student t-test, Pearson correlation analysis, and Spearman rank correlation were used. Results: The mean of $PM_{10}$ and $CO_2$ level were $50.3{\mu}g/m^3$ and 792.1ppm. Sixteen child daycare centers (94.2%) met the guidelines of the $PM_{10}$ level, so did thirteen child daycare centers (76.5%) in the $CO_2$ level. $CO_2$ levels were significantly low in child daycare centers using air cleaners than those do not using them (t=-6.03, p<.001). Types of child daycare centers were significantly correlated to the levels of $CO_2$, which public child daycare centers were low in $CO_2$ levels than those of private child daycare centers (t=-2.54, p=.013). There was no significant correlation between teachers' awareness and management attitude of indoor air quality while teachers' awareness of indoor air quality significantly raised the frequency of carpet cleaning. Methods of cleaning routines were significantly correlated with $PM_{10}$, and $CO_2$ levels. Conclusion: The $PM_{10}$ and $CO_2$ concentrations in child daycare centers were satisfactory. Those conditions are affected by general characteristics of child daycare centers and teachers' attitude regarding management of indoor air quality.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.102-105
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• 1992

Introduction : Isothiazolinone product is one of new preservatives used in cooling tower, paper mill, and general industrial waters.l) It is also effective in controlling bacteria and fungi in the manufacture and storage of dispersed pigments, such as kaolin clays, titanium dioxide, calcium carbonate and others\ulcorner Its broad-spectrum activity, excellent physical and chemical compatibility with anionic, nonionic and cationic surfactants and most organic and inorganic compounds and low toxicity at recommended use levels provide formulators with an effective, economical, and environmentally acceptable alternative to other commercial biocides. It dose not contain or generate formaldehyde and is easy to formulate (1.5% solution is supplied as an aqueous solution), so that it gains advantage over the other preservatives. The active ingredients of the isothiazolinone product are unchlorinated compound (2-methyl-4-isothiazolin-3-one) and chlorinated one (5-chloro-2-methyl-4-isothiazolin-3-one). Methods preferred for the analysis of preservatives are chromatographic methods, especially high performance liquid chromatograph (HPLC). Although several methods were satisfactory in respect to separation, no offical method has been published for the isothiazolinone components. This study was performed to search for an alternative method in order to show flexible operating conditions of HPLC and to reduce assay time.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.477-483
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• 2000

Objectives : To obtain reference values for the pulmonary asbestos and non-asbestos fiber contents of residents in Korea and to compare them with similar results from Japan. Methods : The autopsied lung specimens from 22 deceased people (20 males and 2 females) in Pohang, without any known occupational history of asbestos exposure, were analyzed for incidence of asbestos and non-asbestos fibers by transmission electron microscopy with energy dispersive X-ray analysis after using low temperature ashing procedures. Results : Chrysotite fiber (46.2%) was the major fiber type found in the lungs of the subjects. The asbestos fiber concentrations found in males and females were $0.09\times10^6$ fiberss(g of dry lungs) and $0.30\times10^6$ fibers/(g of dry lungs), respectively, showing a geometric mean concentration $0.09\times10^6$ fibers/(g of dry lung tissue), due to the predominance of males in the sample. The non-asbestos fiber contents in males and females were $4.61\times10^6$ fibers/(g of dry lungs) and $17.79\times10^6$ fibers/(g of dry lungs), respectively, with a geometric mean concentration $5.21\times10^6$ fibers/(g of dry lung tissue). Conclusions : Residents in Pohang had significantly lower levels of both asbestos and non-asbestos fibers than urban residents in Korea. Furthermore, Koreans had significantly lower levels of both asbestos and non-asbestos fibers than Japanese.

• Pediatric Infection and Vaccine
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• v.29 no.1
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• pp.46-53
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• 2022

It is challenging to treat ventriculitis with parenteral treatment alone in some cases because of the difficulty involved in maintaining an appropriate level of antibiotics in cerebrospinal fluid (CSF). We report two cases of ventriculitis who did not respond to intravenous (IV) antibiotics but were successfully treated with intraventricular antibiotics using IV agents. The first case was a four-month-old male patient with X-linked hydrocephalus. He showed ventriculitis due to Klebsiella pneumoniae not producing extended-spectrum β-lactamase and susceptible to third-generation cephalosporins and gentamicin, following ventriculoperitoneal (VP) shunt. His condition did not improve during the 47 days of treatment with IV cefotaxime and meropenem. We achieved improvement in clinical presentation and CSF profile after three times of intraventricular gentamicin injection. The patient was discharged from the hospital with antiepileptic drugs. The second case was a six-month-old female patient with a history of neonatal meningitis complicated with hydrocephalus at one month of age, VP shunt at two months of age, followed by a methicillin-resistant coagulase-negative staphylococci (CoNS) shunt infection with ventriculitis after the shunt operation. CoNS ventriculitis recurred four weeks later. We failed to treat intractable methicillin-resistant CoNS ventriculitis with IV vancomycin for ten days, and thus intraventricular antimicrobial treatment was considered. Five times of intraventricular vancomycin administration led to improvement in clinical parameters. There were only neurological sequelae of delayed language development but no other major complications. Patients in these two cases responded well to intraventricular antibiotics, with negative CSF culture results, and were successfully treated for ventriculitis without serious complications.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.444-449
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• 2023

The current study involved the calculation of air pollutant emission factors (EFs) generated from the incineration of agricultural residues. The process included sample collection, weight measurement, moisture measurement, incineration system configuration, and concentration measurement. The average CO emission factor of gaseous air pollutants from the incineration of barley and wheat agricultural residues was calculated as 0.08289 kg/kg and 0.06665 kg/kg, respectively, whereas the average NO_X emission factor for barley and wheat agricultural residues was determined to be 0.00518 kg/kg and 0.00185 kg/kg, respectively. In the existing air pollutant emission calculation manual, the EF is presented only for barley. Therefore, in this study, we have introduced the EF for wheat, previously absent in the calculation manual. Additionally, the air pollutant calculation manual presents the EF of air pollutants as one value, but in this study, EF values corresponding to 2.5% and 97.5% were presented in consideration of the distribution of experimental values as shown in EMEP/EEA data.

• Journal of agricultural medicine and community health
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• v.36 no.4
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• pp.218-226
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• 2011

Objectives: Paraquat (PQ) is a widely used ionic pesticide that is fatal when ingested accidentally or for suicidal purposes. It is thought that chronic exposure of PQ is related with the development of Parkinson's disease, but epidemiological studies have not yet confirmed that theory. This study attempted to estimate the possibility of environmental PQ exposure through soil and water. Materials and Methods: We analyzed the amount of decomposed PQ solution in wet soil after exposure to ultraviolet light. An artificial rainfall condition was simulated over soil sprayed with PQ to measure the amount of eluted PQ. In addition, PQ was diluted in water from three differently rated rivers and the changes in PQ concentration were measured after ultraviolet exposure over one month. High performance liquid chromatography/ultra violet detection was used to analyze the concentrations of PQ. Results: In the method we used, the recovery rate of PQ showed a precision rate less than 5%, an accuracy greater than 88%, and the calibration equation was y=5538.8x-440.01($R^2$=0.9985). There were no significant differences in the concentrations of PQ obtained from the three specimens over a 1-week period. From the PQ-sprayed soil, the artificial rainfall conditions showed no PQ elution over a 1-month period, and there was no significant differences in PQ concentrations according to ultraviolet exposure among the three samples. Conclusions: PQ remains well adsorbed naturally in soil. However, it may still exist in an integrated state for a long time in the hydrosphere, so the possibility of PQ exposure through drinking water cannot be disqualified.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.261-270
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• 2008

Adjusted water fluoridation has been disputed because of its various effects on human health. Previous studies have been concerned with the difference in bone mineral density (BMD) between water fluoridated (WF) and none water fluoridated (NWF) districts. The aim of this study is to examine whether water fluoridation affects BMD. BMD was measured by dual energy X-ray absorptiometry (DXA). 386 adults(174 males and 212 females) in Ansan (WF) district and 399 adults (176 males and 223 females) in Sihwa (NWF) district, participated in this study. The Ansan and Sihwa districts are similar in residential environment and living class. The relationship between serum fluoride concentration and BMD was also examined by analysis of the serum fluoride concentrations from 402 inhabitants of the Ansan district. In females, the BMD of subjects living in Ansan ($0.457{\pm}0.008$) was a little higher than that of Sihwa subjects ($0.446{\pm}0.008$), although it is not significant, after adjusting for BMI, physical activity level, educational achievement, smoking volume, menopause status, and number of births. However, the BMD of Ansan subjects ($0.532{\pm}0.020$) in their forties was statistically higher than that of Sihwa (0.498{\pm}0.019). No relationship was found in males. In residential periods, there was significant difference (Ansan $0.467{\pm}0.013$, Sihwa $0.434{\pm}0.012$, p=0.0125) in the BMD between females of two districts, particularly in the group of over 6 year long-term inhabitants. On the contrary, there was no remarkable difference in males from the two districts. Serum fluoride concentrations in females were associated with BMD, especially in the age group of forties (p=0.0457). No relationship was observed in the male group. Analysis of adult BMD over the age of 20 in a water fluoridated and a none water fluoridated district, confirms more or less a higher BMD in the water fluoridated (WF) district, especially for females. It is assumed that the difference between two districts came somewhat from the effect of water fluoridation.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1280-1286
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• 2006

Three different virgin activated carbons made of each coal(Calgon), coconut(Samchully) and wood(Picabiol) based activated carbon(AC) were tested for an adsorption performance of 1,4-dioxane in a continuous adsorption column. Breakthrough behavior was Investigated that the breakthrough points of coal, coconut and wood based AC were observed as 3600 bed volumn(BV), 1440 BV and 144 BV respectively. Adsorption capacity(X/M) of coal, coconut and wood based AC was observed. The reported results of adsorption capacity showed that coal based AC was highest(578.9 ${\mu}g/g$), coconut based AC was intermediate(142.3 ${\mu}g/g$) and wood based AC was lowest(7.4 ${\mu}g/g$) due to increasing specific surface area. Moreover, carbon usage rates(CURs) for coal, coconut and wood based AC had been shown as 0.48 g/day, 1.41 g/day and 6.9 g/day respectively. The constant characteristic of the system, k of coal based AC was found to be 91.5 and k of coconut based AC was found to be 17.9. Removal efficiencies of 1,4-dioxane with different ozonation dosages(2 and 5 mg/L) for 20 min ozonation had been shown 38% and 87% respectively. There was no observation for biological removal of 1.4-dioxane by attached micro-organisms when used(3.1 years and over 5 years) biological activated carbon(BAC) without pretreatment of oxidation were employed. When a combination of ozonation(2 mg/L and 5 mg/L) and BAC process for $10{\sim}30$ min was applied, removal efficiency for 1,4-dioxine increased only $2{\sim}6%$ compared to only applying ozonation. Therefore removal efficiency of BAC process prior to using oxidation was proven to negligible. Consequently, the results presented in this paper provide a better insight into the adsorption performance of 1,4-dioxane. This observation suggests that using virgin activated carbon made of coal is the best selection for removal of 1,4-dioxane in the water treatment for an advanced treatment. It is clear from this research that longer EBCT for ozonation or higher ozone concentration are more effective operation methods for removal of 1,4-dioxane than longer EBCT in the BAC process.