• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.38-43
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• 2024

Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.

• Journal of Society of Preventive Korean Medicine
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• v.9 no.2
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• pp.59-75
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• 2005

The experiments were undertaken to evaluate the effects of Bosaengtang in pregnant rats and fetuses. Female Sprague-Dawley rats were orally administered with Bosaengtang at the dose of 5mg/kg/day for 20 days. Pregnant rats were sacrificed at the 20th day of gestation, and observed internal and reproductive organs. Fetuses were randomly selected and fixed in 95% ethanol. Fetuses were stained with alcian blue and alizarin red S, and observed skeletal malformations. The results obtained were as follows : Bosaengtang administered group showed higher maternal body weight than the control group, but both groups showed increase in weight. Bosaengtang administered group showed lower than the control group, and higher liver and kidney weight than the control group, but the differences were minimal. There were no significant changes between the control and treated group in blood chemistry values and hematological values but all the groups were within in normal ranges. There were no significant changes in the number of corpus luteum, implantation, live fetus and implantation rate, delivery rate, late resorption rate, sex ratio, but Bosaengtang administered group showed higher early resorption rate than control group. comparing the control and Bosaengtang group, neonatal body weight and the number of fetuses were increased in Bosaengtang group. The fetuses of dams treated with Oriental medicine didn't showed external malformation. Vertebral and sternal variations were observed in Bosaengtang group, but the differences were not apparent compared to the control group. The number of ribs, cervical, thoracic and lumbar vertebrae were normal. The number of sacral was similar and the number of caudal was increased. Fetuses showed significant difference in the number of caudal vertebrae. (P<0.01) From these results, we can carefully conclude that Bosaengtang showed beneficial effects on maternal body weight, early resorption rate, number of live fetus. There were no significant changes in organ weight, hematoscopy, reproduction organs. External malformation wasn't visible. Skeletal variations were showed in vertebrae and sternum but compared to the control group, these variations weren't much different.

• Journal of Preventive Medicine and Public Health
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• v.33 no.2
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• pp.157-164
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• 2000

Objectives : This study was peformed to determine the reference values of blood lead, manganese, aluminium, and silicon in healthy adults. Methods : The subjects were 132 (67 male and 65 female), and classified to three age groups $(\leq39,\;40\sim49,\;and\;50\leq)$. Blood lead, manganese and aluminium were analyzed by atomic absorption spectrophotometer, and blood silicon was analyzed by direct current plasma optical emission spectrometer. Results : Blood lead levels(geometric mean, S.D) were (3.49, 1.70) ${\mu}g/dL$ in male and (3.04, 1.65) ${\mu}g/dL$ in female, but the difference is not significant, and there was no significant difference between age groups. Mean blood manganese level was $0.99{\pm}0.41{\mu}g/dL$, and there was no significant difference between sex or age groups. Mean blood aluminium level was $0.59{\pm}0.35{\mu}g/dL$, and there was no significant difference between sex or age groups. Mean blood silicon level was $54.41{\pm}27.64{\mu}g/dL$ in male and $43.34{\pm}23.51{\mu}g/dL$ in female, and the level in male was significantly higher than that in female (p<0.05). There was significant difference between age groups, and the oldest showed the highest level in male (p<0.05), but no significant difference between age groups in female. Conclusions : Authors hope that this study would provide basic data for determining reference values and evaluating health effects.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.123-130
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• 2006

Principal aim of this study is to suggest the statistical equation model which can predict an amount of ammonia emission according to the degree of compost maturity during composting livestock manure. Composting process was classified with intial, midterm and final phase based on germination index of compost samples. Total Kjeldahl nitrogen(TKN) and organic matter(OM) were selected as the independent variables available to contribute to ammonia emission from composting pile. Ammonia concentration measured in the samples taken at the intial phase was about 10ppm, sharply increased to 50ppm at the midterm phase, and gradually decreased to about 10ppm. The contents of Total Kjeldahl nitrogen and organic matter through whole composting period were ranged from 0.6 to 1.2% and from 30 to 40%, respectively, were reduced slightly at the midterm phase, but generally showed no constant fluctuation pattern. In estimating ammonia emission with application of the statistical equation model, the coefficients of independent variables at the midterm phase when an average concentration of ammonia was highest showed a relatively high values whereas those at the initial phase when an that of ammonia was lowest indicated a relatively low values. However, no statistical significance was found in the coefficients of independent variables and the equation model. Additionally, the further research, which can include the considerable analysis data with more samples taken than this study, is needed in order to suggest the statistically significant equation model available to predict ammonia emission during composting process.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.104-114
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• 2015

Objectives: The purpose of this study is to investigate the atmospheric concentration of VOCs and the urinary concentration of t,t-MA, HA, MA in the industrial complex of Yeosu, South Jeolla Province. Methods: In order to study seasonal patterns of air concentration of VOCs, measurements were taken at five sampling sites around Yeosu from June 2013 to June 2014. Urinary metabolite excretionsfrom 671 subjects, exposure and comparison area were analyzed. Results: The average concentration of VOCs in the air was 1.53ppb for benzene, 0.73ppb for toluene, 0.22ppb for ethylbenzene, 0.52ppb for xylene and 0.12ppb for styrene. The concentration of benzene was somewhat higher than the year-average standard ($5{\mu}g/m^3$, about 1.5ppb) of the domestic air-environment criteria newly established in 2010.The metabolic concentration of VOCs in the urine of the entire sample was analyzed at $47.76{\mu}g/g\;cr.$, 213.07mg/g cr., and $290.09{\mu}g/g\;cr.$ for t,t-MA, HA, and MA, respectively. Compared with the average values for Korea as presented in the first basic survey of national environmental conservation ( $49.8{\mu}g/g\;cr.$ for t,t-MA, 0.17g/g cr. for HA, and 0.26mg/g cr. for MA), the metabolic concentrations of HA and MA in urine were higher than the average values. Conclusions: The concentration of VOCs in the air and urinary metabolites of the exposed and control areas showed that the concentrations of all substances were higher in the exposed area than in the control area.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.2
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• pp.296-305
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• 1998

A study was performed to evaluate an effect of toluene or ethanol pretreatment on the toluene metabolism. A slight liver damage in rats was induced by administration of 0.2 ml of toluene or 0.2 ml of 50% ethanol per 100 g of body weight intraperitoneally every other day for four weeks except the last day before sacrifice. One day before sacrifice, toluene was administered to rats pretreated ethanol or toluene and the control. Rats were sacrificed at the 1st, the 2nd, the 3rd and the 4th week after the first administration of xenobiotics mentioned above. Based on the histopathological findings, liver weight per body weight, serum alanine aminotransferase and hepatic glutathione content, toluene- or ethanol-pretreated groups showed the reversible liver injury. By the treatment of one dose of toluene, the contents of hippuric acid in urine was higher in the group pretreated with toluene or ethanol than control. The contents of cytochrome P-450, benzylalcohol dehydrogenase and benzaldehyde dehydrogenase activities were generally more increased in toluene- or ethanol-pretreated rats than control. $K_m$ values of the benzylalcohol dehydrogenase in pooled liver samples from toluene- and ethanol-pretreated groups were similar each other. $V_{max}$ values of toluene- or ethanol-pretreated group was higher than control. In conclusion, the toluene metabolism is accelerated in rats pretreated with toluene or ethanol.

• Journal of Environmental Science International
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• v.20 no.7
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• pp.799-809
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• 2011

Objectives: This study is aimed at identifying the influential factors on the pulmonary function of ordinary residents in the surrounding areas of Yeosu Industrial Complex. Methods: The PFT (Pulmonary Function Test) was conducted on the target residents numbering 989 people (male 361, female 628). The exposed group (813 people) resided within the radius of 5km from Yeosu Industrial Complex and the control group (176 people) resided in the radius of more than 15 km from May 2007 to November 2007. The survey also took into account other factors including personal characteristics, life habits, respiratory diseases and allergic symptoms, medical histories, and the living environments of the residents in order to further identify influential factors on pulmonary function. Result: When comparing the PFT values of the exposure groups to the control group of the same city, values of the exposure groups were meaningfully lower with an %$FEV_1$ of 107.05% and %FVC of 100.28%. Conversely, the control group reported an %$FEV_1$ and %FVC of 107.26% and 102.85% respectively, indicating that ambient air pollutants reduce lung function. The odds ratio of asthma diagnosis history increased when a subjects residence was close to a heavily trafficked road, traffic amount was huge, a bed was used, and the family had less than four members. However the results were not statistically meaningful. The odds ratios of abnormal pulmonary function were statistically higher among those with asthma(OR=4.29, CI=1.75-10.56), wheezing (OR=2.59, CI=1.24-5.41), and nasal congestion (OR=2.87, CI=1.36-6.08) (p<0.01). The factors affecting $FEV_1$ were symptoms including asthma, passive smoking and allergic eye disease ($R^2$=0.049, p<0.001). For the FVC symptoms including asthma ($R^2$=0.014, p<0.001) were measured. The analysis showed that FVC decreased with increases in $O_3$ and CO(p<0.01). Furthermore, $FEV_1$ decreased with increases in $O_3$(p<0.01). Conclusions: These results will provide preliminary data for establishing responsive measures to protect the health of residents in industrial complexes from air pollution, and to develop lasting environmental health policies.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7725-7730
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• 2013

Objective: The purpose of this study was to evaluate secondhand smoke (SHS) exposure inside selected public places to provide basic data for the development and promotion of smoke-free policies. Methods: Between March and May 2009, an SHS exposure survey was conducted. $PM_{2.5}$ levels and air nicotine concentrations were measured in hospitals (n=5), government buildings (4), restaurants (10) and entertainment venues (10) in Seoul, Republic of Korea, using a common protocol. Field researchers completed an observational questionnaire to document evidence of active smoking (the smell of cigarette smoke, presence of cigarette butts and witnessing people smoking) and administered a questionnaire regarding building characteristics and smoking policy. Results: Indoor $PM_{2.5}$ levels and air nicotine concentrations were relatively higher in monitoring sites where smoking is not prohibited by law. Entertainment venues had the highest values of $PM_{2.5}$(${\mu}g/m^3$) and air nicotine concentration(${\mu}g/m^3$), which were 7.6 and 67.9 fold higher than those of hospitals, respectively, where the values were the lowest. When evidence of active smoking was present, the mean $PM_{2.5}$ level was 104.9 ${\mu}g/m^3$, i.e., more than 4-fold the level determined by the World Health Organization for 24-hr exposure (25 ${\mu}g/m^3$). Mean indoor air nicotine concentration at monitoring sites with evidence of active smoking was 59-fold higher than at sites without this evidence (2.94 ${\mu}g/m^3$ vs. 0.05 ${\mu}g/m^3$). The results were similar at all specific monitoring sites except restaurants, where mean indoor $PM_{2.5}$ levels did not differ at sites with and without active smoking evidence and indoor air nicotine concentrations were higher in sites without evidence of smoking. Conclusion: Nicotine was detected in most of our monitoring sites, including those where smoking is prohibited by law, such as hospitals, demonstrating that enforcement and compliance with current smoke-free policies in Korea is not adequate to protect against SHS exposure.

• Journal of Environmental Health Sciences
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• v.44 no.4
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• pp.397-407
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• 2018

Objectives: The purpose of this study is to investigate human health risk assessment of indoor air pollutants at small-sized public-use facilities (e.g., daycare centers, hospital and elderly care facilities) that the susceptible population is mainly used. Methods: To assess indoor air quality (IAQ), the concentrations of indoor air contaminants such as HCHO, benzene, toluene, ethylbenzene, xylene, styrene, PM-10, CO, $NO_2$ and $O_3$ in air samples were measured according to the Indoor Air Quality Standard Method. By conducting the questionnaire survey, the major factors influencing IAQ were identified. Human health risk assessment was carried out in the consideration of type of use (user and worker) at 75 daycare centers, 34 hospitals and 40 elderly care facilities. Results: As a result of measurement of indoor air contaminants, the average concentration of HCHO and TVOCs in hospitals was higher than daycare centers and elderly care facilities, about 8.8 and 23.5% of hospitals were exceeded by IAQ standard. In human health risk assessment, for the user of daycare centers and elderly care facilities, the mean carcinogenic risk of HCHO inhalation was higher than acceptable value. Except for HCHO, other values were determined under acceptable risk. Similarly, for the worker of hospitals, the mean carcinogenic risk of HCHO inhalation was higher than acceptable value and other values were evaluated under acceptable risk. In contrast, the risk levels of other contaminants measured in elderly care facilities were acceptable. In the determination of factors influencing IAQ, the construction year, building type, ventilation time, and the use of air cleaner were identified. Conclusions: This study provides the information for establishing the plans of public health management of IAQ at small-sized public-use facilities that have not yet been placed under the regulation. The findings suggest the consideration of human health risk assessment results for the IAQ standards.

• Journal of Environmental Science International
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• v.17 no.9
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• pp.1005-1013
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• 2008

In this study, in order to analyze the air quality of the indoor environments of schools, we measured the indoor, outdoor and personal exposure concentration level of $PM_{10}$ for 40 classrooms(20 old, 20 new) in chungnam area from June 22 to July 19 and from November 21 to December 30, 2003. 1. Old classrooms contained more dust than new classrooms; the average of respirable dust is $43.27\;{\mu}g/m^3$ for new classrooms while $53.38\;{\mu}g/m^3$ for old one. The exposure concentration level of respirable dust in new classrooms were in summer higher outdoors than indoors. The values were indoors $46.71\;{\mu}g/m^3$, outdoors $50.46\;{\mu}g/m^3$, and personal $41.62\;{\mu}g/m^3$. Meanwhile in winter indoors had a higher concentration level than outdoors, the values being indoors $39.11\;{\mu}g/m^3$, outdoors $34.86\;{\mu}g/m^3$, and personal $49.01\;{\mu}g/m^3$. 2. Cr concentration level within dust was slightly higher in summer indoors ($101.50{\pm}32.10\;ng/m^3$) and outdoors ($100.89{\pm}35.18\;ng/m^3$) than winter indoors ($85.80{\pm}48.95\;ng/m^3$) and outdoors ($74.43{\pm}38.93\;ng/m^3$), but in personal concentration level, winter was higher. The results of this research show insufficient understanding of health risks from indoor air pollution, and shows possible health problems to students from school indoor air pollution. As such, a logical and systematic education program for students about the importance of indoor air quality should be carried out. Also the results of $PM_{10}$ concentration level measurements emphasize the need for regular measurements of indoor / outdoor and personal concentration level. New classrooms in particular needs to be used after measuring pollutants and safety, and requires installation of a ventilation device in all classrooms to improve air quality.