• 한국환경보건학회지
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• 제48권1호
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• pp.52-58
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• 2022

Background: Few studies have evaluated the exposure to phthalates via inhalation of floor dust in children's living areas. Objectives: This study evaluated the concentration and exposure level of phthalates emitted from indoor floor dust in children's living areas. Methods: This study utilized the results of a survey conducted by the Ministry of Environment in 2019. Indoor dust was collected from 150 households with children aged 3~7 and 67 daycare centers or local children's centers by using vacuum cleaners. It was analyzed by gas chromatography mass spectrometry. Six types of phthalates were analyzed: Bis (2-ethylhexyl) phthalate (DEHP), Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP), Di-N-octyl phthalate (DNOP), Diisononyl phthalate (DINP), Di -isodecyl phthalate (DIDP). Results: The medians of DEHP concentrations were 1,028 and 1,937 mg/kg in homes and daycare centers, respectively. The median and maximum values of daily intake were calculated by applying the median and 95th percentile values (the upper 5% of the total concentration) in dust measured in the homes. The DEHP median value was 1.6 ㎍/kg/bw/day, and a maximum A value of 7.8 ㎍/kg/bw/day was calculated. When the childcare center values were applied, the median daily intake of DEHP was 3.1 ㎍/kg/bw/day and the maximum value was 29.2 ㎍/kg/bw/day. As a result of calculating the daily intake by integrating the values of home and childcare facilities, the median and maximum values of daily intake were 1.9 and 10.9 ㎍/kg/bw/day, respectively. Conclusions: This study derives phthalate concentrations among the floor dust in homes and childcare facilities where children mainly spend time, and suggests their intake of phthalates through this. In particular, it was newly suggested that the phthalate concentrations in homes and childcare facilities are different, resulting in differences in intake.

• 한국안전학회지
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• 제11권3호
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• pp.25-32
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• 1996

This study is a survey on the effect of working security and worksite environment connected to the worst case of noise and dust which was generated in the manufacturing workshop of machinery and easting. The noise intensity of the manufacturing process tends to increase up to the limited strength of 90db (A) or the higher during the last 4~5 years in 1990~1994. This result requires a significant improvement of worksite environment of unit workshop. The concentration of dust in the gouging process tends to increase to a significantly high level compared with other worksite, which also requires a local ventilation method to reduce the dust diffusion. Organic solvents used most frequently in the manufacturing process machinery were the aromatic hydrocarbons, but were gradually diversed in recent years.

• Asian Journal of Atmospheric Environment
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• 제9권1호
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• pp.91-99
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• 2015

The Multi-wavelength Raman LIDAR (MRL) system was developed to enable a better understanding of the complex properties of aerosols in the atmosphere. In this study, the microphysical, optical, and radiative properties of mixed aerosols were retrieved using the discrete aerosol observation products from the MRL. The dust mixing ratio, which is the proportion of dust particles to the total mixed, was derived using the particle depolarization ratio. It was employed in the retrieval of backscattering and extinction coefficient profiles for dust and non-dust particles. The vertical profiles of aerosol optical properties were then used as input parameters in the inversion algorithm for the retrieval of microphysical parameters including the effective radius, refractive index, and the single scattering albedo (SSA). Those products were successfully applied to an analysis of radiative flux using a radiative transfer model. The relationship between the MRL derived extinction and aerosol radiative forcing (ARF) in short-wavelength was assessed over Gwangju, Korea. The results clearly demonstrate that the MRL-derived extinction profiles are a good surrogate for use in the estimation of optical, microphysical, and radiative properties of aerosols. It is considered that the analytical results shown in this study can be used to provide a better understanding of air quality and the variation of local radiative effects due to aerosols.

• 한국대기환경학회지
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• 제15권5호
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• pp.575-586
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• 1999

The size-resolved number concentrations of aerosols ranging from 0.3 to 25 $mu extrm{m}$ were observed in Seoul and Anmyondo in the west coast of Korea during an Yellow Sand phenomenon in April 1998. Number size distributions of aerosols observed in both places are characterized by decrease in small particles of diameter less than 1${\mu}{\textrm}{m}$ and increase in large size between 1.35 and 10${\mu}{\textrm}{m}$ in heavy dust period. For particles in this size range, there was a good correlation between number concentrations observed in both places during the Yellow Sand episode. On the other hand, the number of small particles less than 0.82${\mu}{\textrm}{m}$ decreased, but the correlation between these particles in both places was enhanced during more intense dust period. The number of coarse particle larger than 10 ${\mu}{\textrm}{m}$ showed a distince diurnal variation without a significant change in amplitude, which was more visible in Seoul. It suggests that these coarse particles were more affected by local sources. Form these results, it was range of 1~10${\mu}{\textrm}{m}$ originated possibly from the dust source regions and the source signature depended on the degree of dust intensity.

• 천문학회보
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• 제46권2호
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• pp.66.1-66.1
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• 2021

Extinction curves observed toward individual Active Galactic Nuclei (AGN) usually show a steep rise toward Far-Ultraviolet (FUV) wavelengths and can be described by the Small Magellanic Cloud (SMC)-like dust model. This feature suggests the dominance of small dust grains of size a < 0.1 ㎛ in the local environment of AGN, but the origin of such small grains is unclear. In this paper, we aim to explain this observed feature by applying the RAdiative Torque Disruption (RATD) to model the extinction of AGN radiation from FUV to Mid-Infrared (MIR) wavelengths. We find that in the intense radiation field of AGN, large composite grains of size a > 0.1 ㎛ are significantly disrupted to smaller sizes by RATD up to dRATD > 100 pc in the polar direction and dRATD ~ 10 pc in the torus region. Consequently, optical-MIR extinction decreases, whereas FUV-near-Ultraviolet extinction increases, producing a steep far-UV rise extinction curve. The resulting total-to selective visual extinction ratio thus significantly drops to RV < 3.1 with decreasing distances to AGN center due to the enhancement of small grains. The dependence of RV with the efficiency of RATD will help us to study the dust properties in the AGN environment via photometric observations. In addition, we suggest that the combination of the strength between RATD and other dust destruction mechanisms that are responsible for destroying very small grains of a <0.05 ㎛ is the key for explaining the dichotomy observed "SMC" and "gray" extinction curve toward many AGN.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권6호
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• pp.9-15
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• 2019

Soil dust emitted from large scale construction sites in urban areas has posed a significant health threats to local residents by exacerbating air quality. Water-spraying (moistening) is commonly practiced to lower the dust emission in construction sites, but its long term effectiveness is highly questionable. In this study, the utility of starch and PVA(polyvinyl alcohol) was investigated in suppression of the soil dust emissions in construction sites in Seoul areas. The efficiency of the two suppressants was tested with test soil sample in a lab-scale wind tunnel box under different concentrations of suppressants and soil textures. Starch and PVA showed the superior ability to suppress soil dust emission as compared to moistening, resulting in PM₁₀ and PM_2.5 lower than the daily limit values of 30 and 15 ㎍/㎥ respectively. PVA showed higher suppression capability than starch for all conditions. The test soils mixed with suppressants also showed dramatically enhanced aggregate stability compared to the non-treated soil.

• 한국산업보건학회지
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• 제29권2호
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• pp.259-269
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• 2019

Objective: This study was conducted to prepare fundamental data and assess the relationship between level of exposure to airborne respirable dust, chest radiation findings, and the results of pulmonary function tests among workers in a cloth manufacturing factory. Methods: The number of total subjects was 144 (124 female and 20 male) workers in a cloth manufacturing factory in the city of Busan. This study measured the concentration of airborne respirable dust by gravimetric analysis and performed pulmonary function testing, and got chest radiation findings from December 1, 2016 to March 31, 2017. Collected data was analyzed using the IBM SPSS statistical package program (ver. 24.0). Results: The mean concentration of respirable dust was the highest in the cutting process. The effecting factors on $FEV_1/FVC$ were age, sex, and working process. The effecting factors on chest radiation findings were doing no exercise and concentration of respirable dust. Conclusions: Based on the above results, the authors consider there to be a need to secure sufficient working space and improve the engineering systems, for example the overall or local ventilation, in order to minimize the exposure to respirable dust. Health education and health promotion activities should also be improved in order to maintain optimal health status. The authors expect further studies to be performed on pulmonary function testing, chest radiation findings, and symptoms related to pulmonary function, including continuous observation, among workers in a cloth manufacturing factory.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2006년도 춘계학술대회 논문집
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• pp.505-506
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• 2006

• 설비공학논문집
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• 제20권4호
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• pp.238-244
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• 2008

This study investigates on the improvement of inhalation effect of hood which attached new device named as "gas-guide-device" in local exhaust ventilation system for the effective elimination of harmful material and dust in manufacturing factory. The gas-guide-device having a diamond shape is composed of width (b) and two sides of a device (X, Y) and its size is selected the industrial hood under application in manufacturing factory after due consideration. In order to investigate the effect of gas-guide-device, numerical and experimental study is performed that the flow velocity is calculated and is measured by a commercial program "COMSOL $Multiphysics^{TM}$" and a hot wire type of anemometer, respectively. The numerical and experimental results are revealed is a similar pattern and flow velocity has improved to hood attached gas-guide-device. Also, the numerical method and result is also verified the dependance. Moreover, the optimum shape and size of gas-guide-device is revealed that the width (b) and the ratio of two sides of gas-guide-device (X, Y) has 125mm and 4 to 6.

• 한국환경보건학회지
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• 제45권6호
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• pp.605-612
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• 2019

Objectives: This study aims to examine receptor-perceived characteristics of environmental and health damage in areas surrounded by industrial workplaces using environmental complaints collected by local governments in Korea. Methods: The environmental complaint data related to workplaces was collected by local governments at each municipality between the years 2015 and 2017. We analyzed the complaint data from the Busan area by the type of business (industry classification), the content of complaints (odor, smoke, noise, and certain health damage), and the frequency of complaints. Results: Among the workplaces examined, industry categories related to retail and service received the highest frequency of complaints related to noise. On the other hand, complaints of dust and odors were raised in higher frequency against manufacturing industries, indicating that air pollution was the main driver of such complaints. Most of the complaints regarding health effects from industries also contained other complaints, such as odor, noise, and dust. Our results indicate that environmental discomfort can lead to more serious health damage, and should be dealt with more seriously. Further management plans for mitigating discomforts such as noise are necessary. Conclusion: This study can be used as background data for identifying the policy priorities related to vulnerable areas polluted by industry and will contribute to improving the environmental health of residents in identified areas.