• 한국학교보건학회지
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• 제16권1호
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• pp.1-8
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• 2003

Purpose : While there have been growing concerns about the effects of Asian dusts on health, there are few studies for relationship between Asian dusts and health outcome. This study was designed to examine the perceived symptoms and behavior change of children during the Asian Dust events. Methods : We surveyed 459 students at an elementary school in Seoul, Korea from November 20th to 27th 2002. Children with parents were asked to return the completed questionnaires within a week. The questionnaires included the sociodemographic factor, previous respiratory disease, and perceived symptom, hospital visits and behavior change during the Asian dusts. Results : The majority of children reported that they restrained going out and outdoor recreational activity during the Asian dusts. The rate of children who worn the mask was 49% and 47% in second grade and fifth grade, respectively. Regarding the perceived symptom during the Asian dusts, the children in 2nd were more likely to have symptom than 5th and there were significant difference between two groups in cough, asthma symptom, dry cough, phlegm and medication for allergy or asthma symptom. In addition, children who had previous disease were more likely to change behavior in order to prevent the effects of Asian dusts. Conclusions : This study suggested that the younger children and children who had past respiratory disease were susceptible to the effect of Asian dusts. There is a need for providing public information and health education to prevent the impact of Asian dusts on health.

• Journal of Preventive Medicine and Public Health
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• 제38권2호
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• pp.141-146
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• 2005

Objectives: Particulate contaminants, such as total and respirable dusts, can harm the health of farm workers via several routes. The principal aims of this field study were to determine the concentrations and emissions of particulate contaminants: total and respirable dusts, in the different types of swine houses used in Korea, and allow objective comparison between Korea and the other countries in terms of swine housing types. Methods: The swine houses investigated in this research were selected with respect to three criteria: the manure removal system, ventilation mode and growth stage of pigs. Measurements of total and respirable dust concentrations and emissions in the swine houses were carried out on 5 housing types at 15 different farm sites per housing type. The swine houses investigated were randomly selected from farms situated within the central districts in Korea: province of Kyung-gi, Chung-buk and Chung-nam. Results: The total and respirable dust concentrations in the swine houses averaged $1.88\;and\;0.64mg/m^3$, ranging from $0.53\;to\;4.37mg/m^3$ and from $0.18\;to\;1.68mg/m^3$, respectively. The highest concentrations of total and respirable dusts were found in the swine houses with deep-litter bed systems: $2.94mg/m^3\;and\;1.14 mg/m^3$, while the lowest concentrations were found in the naturally ventilated buildings with slats: $0.83mg/m^3\;and\;0.24mg/m^3$, respectively (p<0.05). All the swine houses investigated did not exceed the threshold limit values (TLVs) for total ($10mg/m^3$) and respirable ($2.5mg/m^3$) dusts. The mean emissions of total and respirable dusts, per pig (75 kg in terms of live weight) and area ($m^2$), from the swine houses were 97.33 and 9.55 mg/h/pig and $37.14\;and\;12.83mg/h/m^2$, respectively. The swine houses with deep-litter bed systems showed the highest emissions of total and respirable dusts (p<0.05). However, the emissions of total and respirable dusts from the other swine houses were not significantly different (p>0.05). Conclusion: The concentrations and emissions of total and respirable dusts were relatively higher in the swine houses managed with deep-litter bed systems and ventilated naturally of the different swine housing types tested. In further research, more farms than the number used in this research should be investigated, which will present objective and accurate data on the concentrations and emissions of total and respirable dusts in Korean swine houses. In addition, personal sampling should be performed to objectively assess the exposure level of farm workers to particulate contaminants.

• 한국화재소방학회논문지
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• 제15권1호
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• pp.16-22
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• 2001

석유화학플랜트에서 다량 부산되는 가연성 고체인 PP(Polypropylene) 및 LLDPE(Linear low density polyethylene)의 열적특성과 압력용기를 이용하여 산화제와의 혼촉위험성을 조사하였다. 시차주사열량계 및 열중량 분석기를 이용하여 온도에 따른 발열개시온도 및 중량감소를 조사하였고, PP 및 LLDPE의 혼촉위험성을 살펴보고자 소방법상 제1류 위험물로 분류되고 있는 몇 가지 대표적인 산화성 고체와 혼합하여 무게비에 따른 압력용기 내에서의 혼촉위험성을 조사하였다. 또한 가스농도 측정기를 이용하여 PP 및 LLDPE에 대한 연소생성물의 농도를 측정하였다. DSC분석 결과 열분해에 따른 발열 피크가 PP의 경우 220~$250^{\circ}c$ 부근에서 나타나고 있으며, TGA분석결과 PP 및 LLDPE의 분해온도는 각각 200~$350^{\circ}c$, 300~$500^{\circ}c$ 범위이다. 압력용기 시험에 의한 산화제와 PP 및 LLDPE 분진의 혼촉위험성은 오리피스 직경이 감소할수록, 산화제와의 혼촉 무게비가 증가할수록 그리고 시료의 분해온도와 산화제의 분해온도가 비슷한 경우 흔촉위험성이 크게 나타났다. 또한 시료의 연소가스 분석결과 PP의 경우 LLDPE보다 상당히 많은 양의 일 산화탄소가 발생하는 반면 LLDPE가 PP보다 더 많은 양의 이산화탄소 가스를 발생하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.699-704
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• 2001

Until recently, disposal to landfill has been the most convenient way to deal with the increasing amount of residues the shredding industries produce. But the shortage of such disposal sites and the risk that liquid drained from these waste dusts may pollute ground water have increased the environmental pressures to find more effective solutions. The present study is an alternative approach that suggests identifying waste dusts characteristics and selecting an appropriate binder for hazardous materials to reduce the amount of contaminants (mainly lead) that were leaking into the soil. Investigations on the characteristics of automobiles waste dusts show that these materials are composed mainly of cottons and sponge like substances, plastics, rubber, glasses and gravel, metals, and electric wires. Besides, the percentage in weight of organic (inflammable) materials is about 70% and the lead contamination, which has not a ionic but a particulate nature, is particularly remarkable in cottons and sponge like materials. Binding additives such as K-20 and sodium carbonate were not effective but the addition of 5 % of cement (in weight of the investigated sample) followed by a 3-minute stirring and a 4-hour storage could drastically reduce the run off of lead below the maximum authorized level. No addition of water was necessary in this method.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.387-390
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• 2008

This study investigated the influence of electric facilities damaged by dusts and domestic regulations. Its contents included the around circumstance of electric facilities, regulations concerned with the dust, the actual conditions at the scene, the characteristics of dusts and so on. At the set-up the electric facilities, the around circumstances are bad in summer that highly temperature and many moisture. Besides, elements that are judged the corrosive vapours of the large quantity are detected at the sampled dusts. As the results, if dusts covered with electric facilities, It will be a cause for the electric accidents. From the analyzed data of the actual conditions and the sampled dusts, electric facilities maintenance for the viewpoint of the safety can be possible.

• 한국환경보건학회지
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• 제21권2호
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• pp.1-6
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• 1995

Authors investigated the size distribution and mass fraction of dusts in work environment of Changwon industrial complex. Size distribution of suspended dusts in welding and grinding processes were evaluated using ambient cascade impactors. The mass median diameters of dusts were 0.25 to $0.60 \mu m$ at welding sites and 1.20 to $1.92 \mu m$ at grinding sites. Respirable mass fractions were 63.68 to 73.50% at welding sites and 43.24 to 51.47% at grinding sites. Respirable fractions were calculated from the size distribution data for the ACGIH criteria by the respirable particle mass. In case of dust removal system, electrostatic precipitator and bag filter were appropriate for welding process and grinding process, respectively.

• 한국대기환경학회지
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• 제3권2호
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• pp.39-45
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• 1987

Rubber particles emitted from automobile tire tread by abrasion were collected by Andersen sampler with atmospheric dusts. The samples of atmospheric dusts at each stage were analysed for rubber particles by Curie point pyrolysis-gas chromatography with Apiezon grease L column. Pyrolysis was done at 740$^circ$C for 5 seconds. In the pyrogram, NR rubber (bus and truck tire tread) was determined by isoprene peak, and SBR rubber (passenger car tire tread) was determined by styrene peak simultaneously. The size distribution of rubber particles was proportioned with the size of rubber particles. The concentrations of NR and SBR rubber were 0.23 $\mug/m^3$ and 1.31 $\mug/m^3$, respectively, in the atmospheric dusts which were collected from the street in front of Yonsei University on April 1986. The ratio of tire tread rubber in the atmospheric dusts was about 0.63%.

• 환경위생공학
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• 제14권4호
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• pp.93-98
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• 1999

We had investigated combustion properties of rice bran dusts. Decomposition of rice bran dusts with temperature were investigated using DSC and the weight loss according to temperature using TGA in order to find the thermal hazard of rice bran dusts, and the properties of dust explosion in variation of their dust with the same particle size. Using Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after making dust disperse by compressed air, dust explosion experiments have been conducted by varying concentration and size of rice bran dust.According to the results for thermodynamic stability of rice bran dust, there are little change of initiation temperature of heat generation and heating value for used particle size. But initiation temperature of heat generation decreased with high heating rate whereas decomposition heat increased with particle size. Average maximum explosion pressure was $10kgf/cm^2$ for 60/70 mesh and $1.5mg/cm^2$ dust concentration.

• 한국산업보건학회지
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• 제26권3호
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• pp.286-292
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• 2016

Objectives: This study aimed to evaluate the effects of chronical exposure to high-level dusts on cellular immune function. Methods: The subjects were 110 male workers, among whom 60 were chronically exposed to high-level dusts in mica, limestone and iron mines. The remaining 50 were office workers. Ambient total, respirable dust and crystalline silica in the workplace were sampled using personal air samplers and analyzed according to NIOSH method 0500. Serum levels of hydrogen peroxide, lipid peroxide and superoxide misutase activity were measured using absorption chromatography. The subpopulations of CD4+, CD8+, natural killer cells (CD16+) and CD3+ T-lymphocytes were examined by two-color staining using monoclonal antibodies. Results: The concentration of hydrogen peroxide was significantly higher in exposed workers and superoxide dismutase activity was significantly higher in control workers. No significant difference in numbers of T-lymphocyte subpopulations were observed between exposed and control workers. A significant correlation in exposed workers was observed among total dusts, respirable dusts and crystalline silica. Hydrogen peroxide was significantly correlated with total dust (r=0.720, p<0.01), respirable dust (r=0.770, p<0.01) and crystalline silica (r=0.678, p<0.01). Concentration of hydrogen peroxide showed a significantly negative correlation with numbers of CD8+ cells (r=-0.274, p<0.01), CD3+ cells (r=-0.222, p<0.01) and natural killer cells (r=-0.556, p<0.01). Conclusions: These results suggest that chronical exposure to high-level dust affects cellular immune function and effects might mediate through reactive oxygen species and inflammatory response.

• 한국가스학회지
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• 제19권5호
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• pp.75-80
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• 2015

나노 및 마이크로 크기의 알루미늄(Al) 분진은 매우 높은 연소열을 가지고 있어서 로켓 추진체와 폭발물 등을 제조하는 원료로 많이 사용되고 있다. 본 연구에서는 서로 다른 크기의 입자경 (70 nm, 100 nm, $6{\mu}m$, $15{\mu}m$)을 가진 알루미늄 분진을 사용하여 열분해 위험성을 실험적으로 검토하였다. 이를 위해 열중량분석장치(TGA)를 사용하여 승온속도의 변화에 따른 열분해특성을 조사하고 입경이 다른 나노 및 마이크로 크기의 Al에서의 중량개시온도(Temperature of weight gain)로부터 발화온도를 추정하였다. 승온속도가 동일한 조건에서 Al분진의 중량개시온도는 입경이 증가할수록 또한 공기중 승온속도가 증가할수록 증가하는 경향을 나타냈다. 이러한 실험결과로부터 Al분진의 열분해 위험성은 분진 입자경의 증가와 함께 감소할 것으로 추정되었다.