• 월간산업보건
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• s.382
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• pp.11-14
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• 2020

눈, 피부 및 점막 자극의 가능성을 최소화하기 위해 옥시 염화인(phosphorus oxychloride)의 직업적 노출기준 TLV-TWA를 0.1ppm(0.63 mg/㎥)으로 권고하였다. 옥시 염화인 독성의 징후 및 증상으로는 두통, 현기증, 식욕 부진, 메스꺼움, 흉통 및 호흡 곤란이 있고 심한 급성 또는 반복 만성 노출에 의해서는 기관지 폐렴, 폐부종 그리고 신장 손상을 유발한다. 옥시 염화인은 물 또는 습한 공기에서 분해되어 염화수소와 인산을 형성한다. 피부, 감작제(SEN), 발암성 표기와 TLV-STEL을 권고하기에 충분한 자료가 없다.

• 월간산업보건
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• s.383
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• pp.9-12
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• 2020

눈과 호흡기의 자극 가능성을 최소화하기 위해 오염화인(Phosphorus pentachloride)에 대한 직업적 노출기준인 TLV-TWA를 0.1ppm(0.85 mg/㎥)으로 권고하였다. 동물 또는 사람의 오염화인 노출에 대한 독성자료는 매우 제한적이며, 삼염화인(Phosphorus trichloride)과 유사하게 물이나 상대습도가 높은 공기 중에서 염산(Hydrogen chloride)과 인산(Phosphoric acid)으로 가수분해된다. 따라서 삼염화인, 염산 그리고 인산에 대한 TLV Documentation을 참조해야 한다. 피부 흡수(Skin), 감작제(SEN), 발암성 표기에 대한 경고주석과 TLV-STEL을 권고하기에는 유용한 자료가 부족하다.

• 월간산업보건
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• s.385
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• pp.9-13
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• 2020

삼염화인(Phosphorus trichloride)의 노출기준은 눈, 피부, 점막 그리고 호흡기계 기관지 자극의 가능성을 최소화하기 위해 TLV-TWA는 0.2ppm(1.1 mg/㎥), TLV-STEL은 0.5ppm(2.8 mg/㎥)으로 권고하였다. 삼염화인은 직접 피부 접촉 시 심각한 화상을 유발할 수 있으며 공기 중 농도 2ppm~27ppm 범위에서 작업자가 급성 노출되면 인두, 기침, 호흡 곤란 및 심한 천식 기관지염을 유발하는 것으로 보고되었다. 물 또는 습한 공기에서 삼염화인은 염산 및 인산으로 분해된다.(ACGIH의 인산 TLV 문서를 참조하는 것이 필요함). 피부흡수(Skin), 감작제(SEN)의 경고주석과 발암성을 표기하기에는 유용한 자료가 충분하지 않다.

• 월간산업보건
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• s.384
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• pp.19-23
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• 2020

눈, 피부 및 호흡기 자극의 가능성을 최소화하기 위해 오황화인(Phosphorus pentasulfide)에 대한 직업적 노출기준 TLV-TWA는 1 mg/㎥ 그리고 TLV-STEL은 3 mg/㎥으로 권고하였다. 오황화인에 대한 독성 자료는 거의 없으며 오황화인은 습한 공기에서 인산(Phosphoric acid)과 황화수소(Hydrogen sulfide)로 쉽게 가수 분해된다는 사실에 근거하여 인산에 대한 독성 자료로 TLV를 권고하였다.(현재의 인산에 대한 TLV 문서 참조) 피부 흡수(Skin), 감작제(SEN), 그리고 발암성 표기에 대한 경고주석(notation)을 권고하기에는 유용한 자료가 충분하지 않다.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.13-18
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• 2000

The purposes of this study are the analysis of landfill gases(LFGs) in old open dumping landfill site near middle city and offer the useful data for reusing the landfill site as the residental, commercial and other purposes. The concentration of $CO_2$ and $CH_4$ were lower as 8.28 vol% and 1,247 ppm but the concentrations of $NH_3$ and $H_2S$ were 7 times and 12 times higher than TLV-TWA standard. The concentration of $CH_4$ and other gases were lower than the ACGIH criterion. As the result of the environmental assessment on the open dumping landfill, if appears that this landfill is maturation phase and the formation of LFGs is reduced. If the treatment facility of $NH_3$ and $H_2S$ gases is prepared, it can be safely used as this landfill site.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.3-13
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• 1993

This study was conducted at seven degreasing processes in plating plants located in Seoul, Incheon, Ansan, and Taejeon areas from July 21 to august 27, 1992. This study was performed to assess the TWA exposures to trichloroethylene (TCE) and evaluate factors affecting TCE concentrations in degreasing process. Two-Point Eddy Diffusional Model suggested by Wadden et al. was employed to calculalte emission factors according to degreaser type. Results are summarized as follows. 1. The TWA exposures of the degreasing operators ranged from 1.4 ppm to 123 ppm, and those of three plants out of seven were exceeding 50 ppm of both the Korean and U.S. OSHA standards. Degreasing assistant of Plant B, was exposed to 59 ppm. 2. The average concentrations at the distance 0, 1.5, 3.0 m from the degreasers were 1.014, 24, and 18 ppm, respectively, and showed a signifficant difference by distance (p<0.01). 3. The emission of TCE was reduced by installing local exhaust systems, condensers, and refrigeration lines at the degreasers (p<0.01). 4. The major factors related to exposure of operators were workload (r=.9621. p<0.01) and dimensions of degreansing room(r=-.8667, p<0.05). 5. If the air in degreasing room is mixed violently by other factors in addition to diffusion, the emission factors can not be evaluated because the important hypothesis of the Two-Point Eddy Diffusional Model can not be accepted. 6. The ultrasonic degreaser without the local exhaust ststem, condenser, and refrigeration lines emitted TCE three times greater than the ultrasonic degreaser with condenser and refrigeration 1ines only.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.50-57
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• 2020

Objectives: Methyl bromide is a highly toxic substance that can cause systemic poisoning, neurotoxicity, pulmonary edema. Methyl bromide is a widespread fumigation agent used for import and export quarantine, but there is little data on exposure assessment of workers participating in such fumigation. Therefore, this study aims to investigate the exposure level of methyl bromide among workers and the concentration distribution of methyl bromide in the workplace during fumigation. Methods: For this study, one wood tent and one container fumigation area in Pusan, and one wood tent fumigation area in Incheon were investigated over three months from June 2001. Results: Methyl bromide exposure levels for container fumigation workers were from undetected to 1.86 ppm and from undetected to 2.28 ppm for tent fumigation workers as an 8 hr TWA. After opening the container door, the methyl bromide concentration in the container decreased rapidly over time, but the concentration remained over 1 ppm even after about one hour. The concentrations around the tent during its removal were highly affected by wind, but were detected in a range from undetected to 11.97 ppm. Conclusions: This study confirmed that both container and tent fumigation caused workers to exceed the exposure limit of 1 ppm as an 8 hour TWA. In particular, it could be confirmed that a situation exists in which the worker may be exposed to high concentrations of methyl bromide when opening the container or removing the tent due to the nature of the work. Therefore, it is very important to improve working methods and to wear appropriate personal protective equipment.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.18-30
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• 2012

Objectives: The purpose of this study was to estimate the exposure level to extremely low frequency-magnetic fields (ELF-MF) among a selected Korean population using 24-hour personal exposure measurement. Methods: Participants were randomly selected for the measurement of MF exposure under the assumption that the subjects are representative of the overall Korean population. Levels of personal exposure to MF were measured according to the subject's daily activities. Results: The 24-hour time-weighted average (TWA) of 250 participants was $1.56{\pm}4.56$ mG (GM, GSD: 0.79, 2.46 mG). Personal exposure levels for females were higher than for males. The highest personal exposure level was shown in the age group between 20-60 years old. Personal exposure levels according to job category were higher for the non-occupational group than for the occupational group. Conclusions: Our results showed MF exposure exceeding 2 mG per day among 11.3% of the Korean population, indicating a somewhat higher percentage compared to the EMF RAPID Program's results for the U.S population.

• Journal of Environmental Science International
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• v.10 no.3
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• pp.195-200
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• 2001

The personal exposures of nitrogen dioxide(NO$_2$), microenvironmental levels and daily time activity patterns on Seoul subway station workers were measured from February 10 to March 12, 1999. Personal NO$_2$exposure for 24 hours were 29.40$\pm$9.75 ppb. NO$_2$level of occupational environment were 27.87$\pm$7.15 ppb in office, 33.60$\pm$8.64 ppb in platform and 50.13$\pm$13.04 ppb in outdoor. Personal exposure time of subway station workers was constituted as survey results with $7.94\pm$3.00 hours in office, $2.82\pm$1.63 hours in platform and 1 hours in outdoor. With above results, personal $NO_2$exposure distributions on subway station workers in Seoul were estimated with Monte Carlo simulation which uses statistical probabilistic theory on various exposure scenario testing. Some of distributions which did not have any formal patterns were assumed as custom distribution type. Estimated personal occupational $NO_2$exposure using time weighted average (TWA) model was 31.$29\pm$5.57 ppb, which were under Annual Ambient Standard (50ppb) of Korea. Though arithmetic means of measured personal $NO_2$exposure was lower than that of occupational $NO_2$exposure estimated by TWA model, considering probability distribution type simulated, probability distribution of measured personal $NO_2$exposures for 24 hours was over ambient standard with 3.23%, which was higher than those of occupational exposure(0.02%). Further research is needed for reducing these 24 hour $NO_2$personal excess exposures besides occupational exposure on subway station workers in Seoul.

• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.338-345
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• 2006

study investigated the effect of an instruction using generating analogy on scientific conceptual understanding, science learning motivation, attitude toward science instruction, and perception of instruction. Two classes of seventh graders at a middle school in Seoul were randomly assigned to the treatment group and the control group, and they were taught about the motion of molecules for 5 class hours. The instruction for treatment group was developed based on the Glynns Teaching-With-Analogy model. Two-way ANCOVA results revealed that the scores of the treatment group were significantly higher than those of the control group in the conception test. However, there was no significant difference between two groups in the science learning motivation test and the test on the attitude toward science instruction. Survey results on the students perception of instruction showed that generating analogy was hard for the greater part of students, and finding appropriate analog was the most difficult work. Educational implications are discussed.