• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.57-69
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• 2006

Lately human exposure to fine particles smaller than $2.5{\mu}m$ in aerodynamic diameter ($PM_{2.5}$) has become a great concern in Korea due to their possible cause of elevated mortality, lung function decrements, and more frequent hospital admissions for asthma. This study was conducted to investigate seasonal variations of human exposure to residential $PM_{2.5}$ and particle-associated polycyclic aromatic hydrocarbons (PAHs). Ten homes in Chuncheon, Korea were visited for continuous 72 hour sampling of $PM_{2.5}$ in the living rooms using a MiniVol Portable Sampler from December 22, 2002 to November 3, 2003. During the same period, outdoor $PM_{2.5}$ samples were collected on the top of the Natural Sciences Building of Kangwon National University which is located in the middle of the ten households. Samples were analyzed for $PM_{2.5}$ mass concentrations and six selected PAHs. In two smoking homes, the highest $PM_{2.5}$ concentrations were measured ranging from 51.1 to 69.7 {\mu}g/m^3$ on average in all seasons, indicating smoking is a very important contributor to the elevation of indoor particle concentrations. Seasonal comparison showed that indoor particle concentrations were higher than outdoor ones except winter. Total PAH concentrations in smoking homes were highest in winter among the seasons primarily due to low ventilation rate, followed by the outdoor site and nonsmoking homes. BaP toxic equivalents (TEQs) were calculated for five PAHs. The TEQ for smoking homes in winter was highest followed by the outdoor site in winter. It is concluded that smoking and ventilation rate are two important contributors to the elevation of indoor $PM_{2.5}$ and PAH concentrations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.485-492
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• 2013

The effect on collection efficiency with 2-stage vortex finder diameter and back mixing of solid flow due to swirling intensity, turbulence eddies, wall bouncing using the residence time distribution of particle flow in a common and modified cyclone. Higher collection efficiencies of fly ash in a modified cyclone(S = 13, 15cm) are showed than common cyclone. Collection efficiency in modified cyclone was highest at 2-stage vortex finder diameter, S = 13 cm. Variances of residence time distribution and average residence times of glass bead were increased with a diameter(S) of 2-stage vortex finder due to swirling intensity and turbulence eddies. Back mixing of solid flow in a modified cyclone were increased with a gas inlet velocity and showed higher than a common cyclone.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.159-166
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• 1999

This study was conducted to investigate the effects of application of the dolomite particle and the shell powder on soil characteristics, dry matter yield and nutritive value of forages in loam soil at the experimental field of National Livestock Research Institute, Suwon, from 1994 to 1996. Application treatments were control, lime, dolomite 0.5, 2.0, 4.0mm, and shell powder in mixed pasture. Rate of dust occurrence was greatly decreased according to dolomite application and the dissolving rate in soil was highest in shell powder application among treatments. Although there was no significant difference, average dry matter yield of forages for 3 years was slightly increased with the application of lime, shell powder, dolomite 0.5mm, 4.0mm, 2.0mm and control in order. Both Ca and Mg contents of forages were no differences among treatments in 1994. However, all treatments were higher than those of control in 1995. And K and Na contents of forages were no differences among treatments. Lime requirement was greatly increased from 2,630 to 6,150kg per ha with the lapse of time. Although soil hardness was optimum level at first, it was likely to become hard little by little after treatments. Solid phase of soil was lowered a little except for control. Organic matter and available $P_2O_5$ contents of soil were highest in shell powder application among treatments, and K, Ca and Mg contents of soil were no differences among treatments. Ca content was increased a little in 1995, but decreased a little in 1996 compared to that of soil before treatments in 1994. AIso, Mg content was lowered than that of soil before experiment in 1995 and 1996. The results demonstrated that use of dolomite and shell powder as lime substitutes could be reduced dust problem and coast pollution as well as soil improvement. Therefore, it is desirable to apply the dolomite and the shell powder every 3 years in loam soil.

• Journal of Animal Environmental Science
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• v.16 no.2
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• pp.99-108
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• 2010

The principal objective of this study was to investigate the cooling effects of geothermal heat pump system (GHPS) in farrowing house. A total of 96 sows were allocated to 2 pig housings (GHPS and conventional housing) with 48 for four weeks in summer season. During the experimental period of four weeks, the highest outside temperature observed was approximately $34.1^{\circ}C$, GHPS decrease indoor temperature of pig housing up to $30.9^{\circ}C$, but conventional pig housing was similar to outside temperature. Dust concentrations (maximum 61.4%) of particulate matter less than $10{\mu}m$ (PM 10) in GHPS-housing were lower than the conventional housing. GHPS showed no signigicant difference in carbon dioxide emission, whereas the ammonia gas concentration was significantly decreased in GHPS-housing compared to that of conventional housing. Sows in GHPS-housing showed significantly lower respiratory rate than those of the control group. GHPS did not affect hormone level, litter size and birth weight, but weaning weight of piglets was influenced by GHPS. Feed consumption of sows was significantly increased in GHPS-housing compared to the conventional hosing. These results suggest that GHPS decrease dust concentration, ammonia gas emission and indoor temperature of pig housing and may affect performance in sows and weaned piglets.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.129-136
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• 2010

This study is to investigate experimentally the engineering characteristics of cement mortar according to the replacement method and contents of recycled aggregate powder (RP) by collecting the recycled aggregate powder with the maximum size of below 0.08 mm and 0.15 mm. then, the results of the study can be summarized as follows. The flow of flesh mortar represented a trend in decreasing while the recycled aggregate powder was substituted as it is compared with that of plain. In addition, in case of correlation between tests, it appeared that the correlation between flow and ring flow is big. In the case of the characteristics of hardened mortar, the strength showed more improvements as the RP was substituted to aggregate than the case, which is substituted to aggregate. In addition, it was verified that the results in which the RP was substituted to aggregate by 5% represented similar values to that of the plain according to the passage of age.

• Journal of the Korean Data and Information Science Society
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• v.28 no.3
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• pp.473-481
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• 2017

It is well known that the air quality of 92% of the world is known to exceed the standard of WTO and the death caused by air pollution is almost 6 million per year. The $PM_{2.5}$ concentration in Korea is the second most serious among the OECD countries following Turkey. Since the $PM_{2.5}$ has a direct effect on the respiratory system, it has been actively studied in domestic and foreign countries. But current research on the $PM_{2.5}$ is limited in weather factor or air pollutants. In this paper, we consider the influence of spatial neighbor with weather factor or air pollutants using spatial panel model. We applied the proposed method to 25 borough of Seoul in Korea. The result shows a significant effect of spatial neighbor on the $PM_{2.5}$ concentration fields.

• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.45-56
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• 2006

This study was conducted to investigate seasonal distributions of fine particles ($PM_{2.5}$) and associated polycyclic aromatic hydrocarbons (PAHs) at three cities. $PM_{2.5}$ samples were collected on glass fiber filters at urban (Chuncheon), metropolitan (Seoul), and industrial complex sites (Ulsan) from September, 2002 to February, 2004 using the Andersen FH 95 Particulate Sampler. About five 24-hour samples were collected from each site per season. The filters were analyzed for mass and six selected PAHs concentrations. $PM_{2.5}$ concentrations were the highest either in winter or spring, which could be attributed to the increase of fossil fuel combustion in winter or the transport of yellow sand to the Korean peninsula from China in spring, respectively. Regional $PM_{2.5}$ concentrations were higher in the order of Seoul>Chuncheon>Ulsan without statistical difference among cities. The filters were extracted using dichloromethane in an ultrasonicator and analyzed for six PAHs (anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, and benzo[a]pyrene) with HPLC. Total PAHs concentrations were statistically different among seasons in each site, and the highest concentrations were observed in winter at each sampling site. For total samples collected, the median total PAHs concentrations in Chuncheon ($4.6ng/m^3$) and Seoul ($4.4ng/m^3$) were approximately two times higher than that in Ulsan ($2.1ng/m^3$). Chrysene was a component found in the highest proportion among total PAHs at each site. Carcinogenic risks calculated based on the BaP toxic equivalency factors (TEFs) over the whole sampling period were higher in the order of Chuncheon>Seoul>Ulsan. This study suggests that the atmosphere of Chuncheon is contaminated with particulate matter and PAHs at the levels equivalent to those of Seoul and that an appropriate measure needs to be taken to mitigate human health risks from inhalation exposure to airborne fine particles.

• Clean Technology
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• v.6 no.2
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• pp.121-127
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• 2000

There are several kinds of hazardous materials in incinerator flue gas, such as particulate matter, acid gas, heavy metal, dioxin, etc. The activated carbon adsorption is considered as one of the methods removing dioxin from flue gas. Without any additional equipment and facilities, the activated carbon was mixed with lime and sprayed in the semi-drying reactor of an incinerator and filtered in the bag filter, and its efficiency of removing hazardous organic material was investigated. 1,2-dichlorobenzene (o-DCB) was used as a precursor material of dioxin and the effects of the activated carbon amount, the operating temperature of the reactor, and the atomizer r.p.m were measured and analyzed. Experimental results showed that the optimum outlet temperature of the reactor was $145^{\circ}C$ considering the performance of the bag filter, and the adsorption performance improved with the increase of the atomizer r.p.m. Also the performance of removing o-DCB in the bag filter is higher than of the semi-drying reactor.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.2
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• pp.216-232
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• 2016

In present, the Seoul City is undergoing traffic congestion problems caused by rapid urbanization and population growth. Thus the City government has reorganized the mass transportation system since 2004 and the subway has become a very important means for public transit. Since the subway system is typically a closed environment, the indoor air quality issues have often raised by the public. Especially since a huge amount of PM (particulate matter) is emitted from ground tunnels passing through the subway train, it is now necessary to assess the characteristics and behaviors of fine PM inside the tunnel. In this study, the concentration patterns of $PM_1$, $PM_{2.5}$, and $PM_{10}$ in the Seoul subway line-2 were analyzed by real-time measurement during winter (Jan 13, 2015) and summer (Aug 7, 2015). The line-2 consisting of 51 stations is the most busy circular line in Seoul having the railway of 60.2 km length. The the one-day average $PM_{10}$ concentrations were $148{\mu}g/m^3$ in winter and $66.3{\mu}g/m^3$ in summer and $PM_{2.5}$ concentrations were $118{\mu}g/m^3$ and $58.5{\mu}g/m^3$, respectively. The $PM_{2.5}/PM_{10}$ ratio in the underground tunnel was lower than the outdoor ratio and also the ratio in summer is higher than in winter. Further the study examined structural types of underground subsections to explain the patterns of elevated PM concentrations in the line-2. The subsections showing high PM concentration have longer track, shorter curvature radius, and farther from the outdoor stations. We also estimated the outdoor PM concentrations near each station by a spatial statistical analysis using the $PM_{10}$ data obtained from the 40 Seoul Monitoring Sites, and further we calculated $PM_{2.5}/PM_{10}$ and $PM_1/PM_{10}$ mass ratios near the outdoor subway stations by using our observed outdoor $PM_1$, $PM_{2.5}$, and $PM_{10}$ data. Finally, we could develop pollution maps for outdoor $PM_1$ and $PM_{2.5}$ near the line-2 by using the kriging method in spatial analysis. This methodology may help to utilize existing $PM_{10}$ database when managing and control fine particle problems in Korea.

• Journal of Conservation Science
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• v.25 no.1
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• pp.25-38
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• 2009

The Gyeongju Seokbinggo (Treasure No. 66) is an ice-storing stone warehouse, consisting mainly of alkaligranite which shows milky white color and medium-grained textures with drusy cavities. As results of deterioration assessment, the deterioration rates were determined as crack (12.5%), disjoining (6.7%), breaking-out (25.1%), exfoliation (20.9%), efflorescence (6.5%), brown discoloration (9.8%), darkgray discoloration (2.0%) and biological discoloration (36.5%). Comprehensive physical deterioration rate and discoloration rate were calculated as 43.7% and 68.7%, respectively, that indicates the Seokbinggo has been severely weathered. Indoor relative humidity was above 90% except in winter season. Indoor microclimate was hardly fluctuating although indoor microclimate was dependent on the outdoor climate. The main cause of deterioration was high relative humidity and a long time of wetness due to penetration of rain, underground water and condensation. It was identified that the water brought out biological discoloration, dissolution of minerals, structural movement and efflorescence, and the dust from the ground soil in front of the entrance accelerated brown and dark gray discoloration on the stone surface.