• 한국환경보건학회지
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• 제47권5호
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• pp.410-424
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• 2021

Background: Subway stations have the characteristics of being located underground and are a representative public-use facility used by an unspecified number of people. As concerns about indoor air quality (IAQ) increase, various management measures are being implemented. However, there are few systematic studies and cases of long-term continuous measurement of underground station air quality. Objectives: The purpose of this study is to analyze changes and factors influencing IAQ in subway stations through real-time continuous long-term measurement using IoT-based IAQ sensing equipment, and to evaluate the IAQ improvement effect of a bio-filter system. Methods: The IAQ of a subway station in Seoul was measured using IoT-based sensing equipment. A bio-filter system was installed after collecting the background concentrations for about five months. Based on the data collected over about 21 months, changes in indoor air quality and influencing factors were analyzed and the reduction effect of the bio-filter system was evaluated. Results: As a result of the analysis, PM₁₀, PM_2.5, and CO₂ increased during rush hour according to the change in the number of passengers, and PM₁₀ and PM_2.5 concentrations were high when a PM warning/watch was issued. There was an effect of improving IAQ with the installation of the bio-filter system. The reduction rate of a new-bio-filter system with improved efficiency was higher than that of the existing bio-filter system. Factors affecting PM_2.5 in the subway station were the outdoor PM_2.5, platform PM_2.5, and the number of passengers. Conclusions: The IAQ in a subway station is affected by passengers, ventilation through the air supply and exhaust, and the spread of particulate matter generated by train operation. Based on these results, it is expected that IAQ can be efficiently improved if a bio-filter system with improved efficiency is developed in consideration of the factors affecting IAQ and proper placement.

• 한국환경보건학회지
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• 제32권2호
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• pp.171-178
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• 2006

The objectives of this study were to investigate the formation of trihalomethanes(THMs) and to compare the concentration level of THMs of swimming pools water by different disinfection methods such as chlorine, ozone-chlorine, and salt brine electrolysis generator (SBEG). The concentration of chloroform was the highest in the chlorine system, and the SBEG was the highest in the production of bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform. The average concentration of total trihalomethanes (TTHMs) in three disinfection systems were $64.5{\pm}27.4mg/l(SBEG),\;43.8{\pm}22.3mg/l(chlorine)$, and $30.6{\pm}16.1mg/l(ozone-chlorine)$, respectively. In chlorine and ozone-chlorine disinfection system, chloroform concentration was highest, followed by BDCN, then DBCM. In the SBEG, TTHMs was composed of 42% of chloroform, 28.9% of bromoform, 15.1% of BDCM and 14% of DBCM, respectively. The strongest correlation was obtained in the levels of chloroform and TTHMs in chlorine, and ozone-chlorine disinfection systems from both indoor and outdoor swimming pools ($r=0.989{\sim}0.999$, p<0.01). In the SBEG, the levels of BDCM and TTHMs showed a good correlation (r=0.913, p<0.01). In chlorine and ozone-chlorine disinfection systems at indoor swimming pools, pH, TOC and $KMnO_4$ consumption showed strong correlation with chloroform and TTHMs concentrations (p<0.01). In the SBEG, pH and TOC were also strongly correlated with chloroform (p<0.01). pH and TTHMs were correlated as well (p<0.05).

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.76-86
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• 2014

Purpose: The objective of this study was to measure emissions of gases (ammonia ($NH_3$), hydrogen sulfide ($H_2S$) and carbon dioxide ($CO_2$)), volatile organic compounds (VOC) and odor from two shallow pit pig nursery rooms. Gas and odor reduction practices for swine operations based on the literature were also discussed. Methods: This study was conducted for 60 days at a commercial swine nursery facility which consisted of four identical rooms with mechanical ventilations. Two rooms (room 1 (R1) and room 2 (R2)) with different pig numbers and ventilation rates were used in this study. The pig manure from both the R1 and R2 were characterized. Indoor/outdoor temperatures, ventilation rates/duration, $NH_3$, $H_2S$, $CO_2$, and VOC concentrations of the ventilation air were measured periodically (3-5 times/week). Odor concentrations of the ventilations were measured two times on two days. Three different types of gas and odor reduction practices (diet control, chemical method, and biological method) were discussed in this study. Results: The volatile solids to total solids ratio (VS/TS) and crude protein (CP) value of pig manure indicated the pig manure had high potential for gas and odor emissions. The $NH_3$, $H_2S$, $CO_2$ and VOC concentrations were measured in the ranges of 1.0-13.3, 0.1-5.7, 1600-3000 and 0.0-1.83 ppm, respectively. The $NH_3$ concentrations were found significantly higher than $H_2S$ concentrations for both rooms. The odor concentrations were measured in the range of $2853-4432OU_E/m^3$. There was significant difference in odor concentrations between the two rooms which was due to difference in pig numbers and ventilation duration. The literature studies showed that simultaneous use of dietary control and biofiltration practices will be more effective and environmentally friendly for gas and odor reductions from pig barns. Conclusions: The gas and odor concentrations measured in the ventilation air from the pig rooms indicate an acute need for using gas and odor mitigation technologies. Adopting diet control and biofiltration practices simultaneously could be the best option for mitigating gas and odor emissions from pig barns.

• Environmental Analysis Health and Toxicology
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• 제18권4호
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• pp.255-269
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• 2003

The objective of this study was to estimate human exposure to benzo (a)pyrene through multimedia/multi-pathway exposure scenario. The human exposure scenario for benzo(a)pyrene was consisted of 12 multiple exposure pathways, and the multipathway human exposure model based on this scenario constituted. In this study, the multipathway human exposure model was used to estimate the concentrations in the exposure contact media, human intake factors and lifetime average daily dose (LAD $D_{model}$) of benzo(a)pyrene in the environment. Sensitivity analysis was performed to identify the important parameters and Monte-Carlo simulation was undertaken to examine the uncertainty of the model. The total LAD $D_{model}$ was estimated to be 5.52${\times}$10$^{-7}$ mg/kg-day (2.06${\times}$10$^{-7}$ -8.65${\times}$10$^{-7}$ mg/kg-day) using the multipathway human exposure model. The inhalation dose accounted for 78% of the total LADD, whereas ingestion and dermal contact intake accounted for 20.2% and 1.8% of the total exposure, respectively. Based on the sensitivity analysis, the most significant contributing input parameter was benzo (a)pyrene concentration of ambient air. Consequently, exposure via inhalation in outdoor/indoor air was the highest compared with the exposure via other medium/pathways.

• Environmental Engineering Research
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• 제21권3호
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• pp.241-246
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• 2016

This paper discusses the influence of organic matter contained in aggregate on the emission characteristic of ammonia ($NH_3$) from cement mortar. $NH_3$ can be released to indoor-outdoor environment through diffusion in mortar (or concrete) and have resulted in the increasing air pollution, and especially well known as a harmful gas for the human body. The concentration of $NH_3$ released from cement concrete was then compared to the contents of organic matter contained in the aggregate. The result indicates that the contents of organic matter in the aggregate significantly differ with types of aggregate from different areas of production. The organic matter becomes organic nitrogen through the process of microbial breakdown for a certain period and pure ammonium ion ($NH_4{^+}$) is produced from the organic nitrogen. The $NH_4{^+}$ was reacted with alkaline elements in the cement and released as $NH_3$ from cement concrete through a volatile process. The released $NH_3$ was proportional to the contents of $NH_4{^+}$ adsorbed in the aggregate from different areas of production and the concentrations of $NH_3$ emission from cement mortar according to the aggregate differ by more than 4 times.

• Environmental Analysis Health and Toxicology
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• 제22권2호통권57호
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• pp.103-109
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• 2007

대기 중 휘발성유기화합물류(VOCs)의 배출원은 매우 다양하며, 특히, 공단에서 배출되는 VOCs 노출로 인한 공단 주변거주지역 주민에게 배출특성 및 물질별 독성에 따라 유해한 건강 영향을 끼칠 가능성이 있다. 또한 일반가정에서의 자체 실내 오염원 또한 휘발성유기화합물류의 노출의 한 원인이다. 본 연구에서는 공단 주변 거주지역 및 동일 행정구역상의 비교지역을 선정하여 공단배출로 인한 실내유입 VOCs 노출 및 자체 실내오염원으로 인한 농도분포 및 기여정도를 조사하였다. 본 연구에서 공단주변 거주지역 및 비교지역의 조사된 실내 평균 농도는 MTBE 2.24, $2.47{\mu}g/m^3$, benzene 9.82, $8.51{\mu}g/m^3$, toluene 103.80, $83.57{\mu}g/m^3$, ethylbenzene 36.45, $15.52{\mu}g/m^3$, xylene 26.27, $1.00{\mu}g/m^34로 비교지역 거주지에 비해 공단지역 주변거주지의 실내공기 중 VOCs 의 농도가 높은 것으로 나타났다. 최종적으로 I/O ratio를 비교한 결과 조사 거주지 모두 자체 실내오염원이 있는 것으로 관찰되었고, 공단지역 주변거주지의 경우 공단의 VOCs 배출로 의해 추가 노출이 되는 것으로 각각 조사되었다.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2447-2453
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• 2023

The radioactivity concentrations of Naturally Occurring Radioactive Materials (NORM) i.e., ²²⁶Ra, ²³²Th, and ⁴K in various chemical fertilizers being used in the agricultural soil of Pakistan were determined utilizing gamma spectrometry by employing a High Purity Germanium (HPGe) detector. The radioactivity concentrations of ²²⁶Ra, ²³²Th, and ⁴K extended from 2.58 ± 0.8-265.7 ± 8.8 Bq kg^-1, 1.53 ± 0.14-76.6 ± 1.07 Bq kg^-1 and 36.5 ± 1.34-15606.7 ± 30.2 Bq kg^-1 respectively. The radiological hazard parameters such as internal and external indices and annual effective dose rates were calculated, while excessive lifetime cancer risk factors for the indoor and outdoor areas were found in the range from 0.3×10^-3 to 10.723×10^-3 and 0.03×10^-3 to 2.7948×10^-3 of most fertilizers, however, some values were slightly higher than the UNSCEAR (The United Nations Scientific Committee on the Effects of Atomic Radiation) recommended values for potash-containing fertilizers such as MOP (Muriate of Potash).

• 한국산업보건학회지
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• 제20권1호
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• pp.41-46
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• 2010

The purpose of this study is to assess the level of fungi concentration in the university laboratories in Seoul, Korea, and to investigate factors contributing to these concentrations. The samples were taken from three spots in each laboratory; the top of sink, the center of laboratory, and the front of ventilation system, i.e fume hood at the chemical laboratory and clean bench/biosafety cabinet at the microbial laboratory. Air samples were collected using the single-stage Anderson sampler (Quick Take 30) at a flow rate of 28.3 l/min for 5 min on nutrient media in Petri-dishes located on the impactor. Fifty-two air samples were collected from 19 different laboratories (13 microbiology laboratories, 6 chemistry laboratories) in the university, and concentrations of airborne fungi showed no significant difference (p>0.05) between microbiology and chemistry laboratory, and also no significant difference at three locations (sink, center, front of ventilation system) in microbiology and chemistry laboratories. Average concentrations of fungi in 19 laboratories ranged from 7 to 459 cfu/$m^3$, with an overall Geometric Mean of 52 cfu/$m^3$. Airborne fungi concentrations of 6 samples (12 %) exceeded 150 cfu/$m^3$, the guideline of WHO. The ratios of Indoor/Outdoor for airborne fungi ranged from 0.2 to 4.8 (mean = 1.6). Related factors were measured such as relative humidity, temperature, and laboratory area. Temperature and laboratory area showed no significant relations to concentrations of airborne fungi except for relative humidity in the laboratory Concentrations of fungi were significant different (p<0.01) between rainy or cloudy and sunny. However, there was no significant difference between general ventilation and nongeneral ventilation.

• 한국환경보건학회지
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• 제40권4호
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• pp.279-293
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• 2014

Objectives: Children are more susceptible to heavy metal toxicity than adults. The purpose of this study was to evaluate heavy metal concentrations in the blood of Korean preschoolers and investigate the association between metals in blood and related factors. Methods: A total of 512 subjects from 36 to 83 months of age were sampled. A questionnaire survey was performed and the levels of lead, mercury and cadmium were measured in the blood samples of all subjects. Their parents were interviewed in order to obtain information on basic characteristics, dietary patterns, socio-economic factors, and indoor/outdoor environment of the preschoolers. Multiple linear regression was used to analyze the association between the above factors and lead, mercury or cadmium concentrations. Results: The geometric mean concentrations of lead, mercury and cadmium in the blood were $1.45{\pm}1.58{\mu}g/dL$, $2.14{\pm}1.74{\mu}g/dL$ and $0.23{\pm}1.91{\mu}g/dL$, respectively. Results from multiple linear regression analysis showed that blood lead levels were associated with birth weight and paternal smoking status. Daily mercury intake from food and maternal education were also shown to influence mercury concentrations in blood. Also, blood cadmium concentrations were associated with maternal age and having a bus garage near the place of residence. Conclusion: This study suggests that smoking status, dietary patterns and the environmental status near the residence should be considered as important factors for preventable sources of heavy metal exposure in preschoolers.

• Asian-Australasian Journal of Animal Sciences
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• 제27권5호
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• pp.726-732
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• 2014

The objective of this study was to investigate the effect of maintenance system as well as the effect of Se, Zn, and vitamin E supplementation of ram-lambs on the slaughter value and concentration of mineral elements in the loin muscle of lambs. The experiment was conducted on 72 Polish Merino ram-lambs divided into three groups: group C, indoor with no supplement, 19 lambs; S, indoor with supplement, 23 lambs; G, outdoor with no supplement, 30 lambs. From birth all the lambs were maintained indoor with their dams and then weaned at the age of 8 weeks. The rams from group C and S were placed in individual straw-bedded pens and fattened individually with concentrate mixture offered ad libitum until the age of 16 weeks. The lambs from group G were grazed every day from May to July (2 months). During the fattening period each lamb from the supplemented group S was administered per os 1 mL 0.1% $Na_2SeO_4$ (Se, 0.42 mg), 3 mL 10% $ZnSO_4$ (Zn, 68 mg), and 1 mL premix protect vitamin E (0.1 g ${\alpha}$-tocopherol, 5 mg lysine, 5 mg methionine) daily. A comparison of half carcasses across the groups has shown no difference between the control group and the one with supplements, while the weight of half carcasses in the grazing group was smaller in comparison with groups C and S (p<0.001). The meat content in the pelvic limb showed no differences across all groups under study. The pelvic limb of grazing lambs contained less fat compared to the control and supplemented groups (p<0.001). The concentrations of Se and Zn in the blood plasma of ram-lambs from the supplemented group were significantly higher than for the control and grazing lambs. Inorganic Se and Zn supplementation with vitamin E to the diet of lambs increased Se and Zn levels in loin muscle (p<0.001) to $0.46{\mu}g/g$ and $32.9{\mu}g/g$ in fresh tissue, respectively.