• 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 Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.476-483
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• 2010

Total bacterial populations were cultured from the Hydroball cultivation media in the rhizospheres of 9 different plants including $Hedera$ $helix$ L. and $Dracaena$ $deremensis$ cv. Warneckii Compacta, etc. These cultured bacterial populations were studied to test if the bacterial populations in the plant growing pots may play a role on removal of volatile organic compounds (VOCs) such as benzene and toluene in the air. To meet this objective, first, we tested the possibility of removal of VOCs by the cultured total bacteria alone. The residual rates of benzene by the inoculation of total bacterial populations from the different plant growth media were significantly different, ranging from 0.741-1.000 of $Spathiphyllum$ $wallisii$ 'Regal', $Pachira$ $aquatica$, $Ficus$ $elastica$, $Dieffenbachia$ sp. 'Marrianne' Hort., $Chamaedorea$ $elegans$, compared to the control with residual rate of 0.596 (LSD, $P$=0.05). This trend was also similar with toluene, depending on different plants. Based on these results, we inoculated the bacterial population cultured from $P.$ $aquatica$ into the plant-growing pots of $P.$ $aquatica$, $F.$ $elastica$, and $S.$ $podophyllum$ inside the chamber followed by the VOCs injection. The inoculated bacteria had significant effect on the removal of benzene and toluene, compared to the removal efficacy by the plants without inoculation, indicating that microbes in the rhizosphere could play a significant role on the removal of VOCs along with plants.

• Journal of Animal Environmental Science
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• v.11 no.1
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• pp.1-10
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• 2005

This study was carried out to measure the environmental related parameters from two types of swine houses. Indoor temperature, relative humidity, carbon dioxide level, ammonia concentration and emission were measures every 2 minutes from each house with portable monitoring units. Carbon dioxide concentration balance was used to estimate the ventilation rates of the different houses. Daily ammonia concentrations in the growing-finishing and farrowing houses ranged from 2 to 17 ppm and 6 to 15 ppm respectively. The daily ammonia emission rate from the manure averaged 4.37 g/h$\cdot$500 kg from growing-finishing house and 4.82 g/h$\cdot$500 kg from the farrowing house. The above findings proved that summer season was associated with higher ammonia emission rates due to higher ventilation rate and ambient air temperature.

• Journal of Animal Environmental Science
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• v.13 no.3
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• pp.195-200
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• 2007

Management of odors is essential to swine industry in the Republic of Korea. This study was conducted to evaluate the odor removal efficiency of biofilter ducting systems. Rice straw and auto clave concrete(ALC) were used as filter medium. The ventilation fans(5 units, diameter: 500 mm) at the side wall of a growing pig housing were connected to a biofilter using a duct. The size of a biofilter is $2.5{\times}2{\times}1.2(W{\times}L{\times}H)$. The air velocities at the 300 mm above rice straw and ALC were 0.77 and 0.56 m/s, respectively. Ammonia concentration at the outlet of rice straw and ALC media were 2 and 3 ppm, respectively. Dust concentrations were also measured. The dust concentrations of rice straw and ALC were 93, $32\;mg/m^3$, respectively. There was no significant difference between filter mediums in terms of carbon dioxide concentrations(rice straw: 320, ALC: 270 mg/l). The concentration of hydrogen sulfide was stable over the experimentation. The actual concentrations of hydrogen sulfide were 4, 3 and 3 ppm at the days of 7, 21 and 36, respectively. These results suggest that biofilter ducting systems may remove odors from pig house effectively.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.24-30
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• 2015

This study was conducted to select proper light intensity, pot media, and fertilization level for potted Hepatica asiatica Nakai native to Korea. The plants were grown under various light intensities (shading rate, 52, 82, 90, 97%) imposed by shading net. Plants grown with 52% shading showed a low survival rate (65%). Survival rate increased as shading increased, with over 80% survival in shading above 90%. Growth indexes such as fresh weight and leaf number did not show any significant difference between shading treatments. Plants grown in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30, v/v/v) or river sand:fertilizer-amended media:bark (50:20:30) showed over 85% survival. However, plants grown in a soil mixture of river sand:fertilizer-amended media:Kanumatsuchi (50:30:20) or upland:river sand (40:60) showed very low survival, below 60%. Leaf number and plant height were the highest in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30) as well. To select a proper fertilization level for H. asiatica, hyponex solution diluted 1,000- or 2,000-fold were applied weekly or biweekly. The survival rate was lowest at weekly application with 1,000-fold diluted solution, and no significant difference was observed between other treatments. In conclusion, H. asiatica exhibits preferences for very low light intensity and soil with air permeability, and is adaptable to a broad range of fertilization levels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.463-469
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• 2009

We performed the experimental study on the control of suspended dust in a cement packaging process for various ventilation systems. To effectively remove the dust generated in the cement packaging process, three different kinds of ventilation system, such as local exhaust ventilation, electrostatic scrubber, and local air supply system, were adopted. Dust concentrations in the packaging process were measured with the variation of the airflow rate of the ventilation systems and then their ventilation performance were evaluated. From the results, we knew that the ventilation performance was the best when the local exhaust ventilation and the electrostatic scrubber were simultaneously operated in the packaging process. In the electrostatic scrubber system, the effect of the airflow rate on the indoor dust removal efficiency was negligible so hat he system ust be operated at $2,700m^3/h$ for saving power consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.114-120
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• 1998

The spawning behavior, development of eggs and larvae of the Korea freshwater goby, Rhinogobius brunneus (Temminck et Schlegel) were studied. The eggs were spawned as a one-layer mass, hanging from the underside of a small pebble, and guarded by one male. The eggs were elliptic, about 1.48 mm in length and 0.65 mm in breadth, with a round top and a somewhat flat base with glutinous fibers. Hatching in the indoor tank with $17.0^{\circ}C$ in mean water temperature started from the 146 hours after fertilization. In the late developing stages, the embryo moved and freely changed its head to face the free tip of the chorion (normal egg) or to the basal end with a boundle of adhesive filaments (agrippa egg). Newly-hatched larvae were $3.10\~3.30$ mm in total length (mean: 3.22 mm), and mouth and anus were not yet open. Melanophores were present on the air- bladder, around the anus, and on the ventral part of the caudal region. The larva $3\~4$ days old transformed to postlarval stage, and they were $3.30\~3.85$ mm in total length (mean: 3.60 mm). As yolk sac and oil globules werw nearly absorbed, mouth and anus were open, and they fed rotifers actively. In $20\~22$ days after hatching the larvae grew to 5.85 mm in 71, and the caudal notochord flex at $45^{\circ}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2083-2090
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• 2008

In this paper, we propose a method for control of temperature and the direction of wind in an air-cooler using thermal images and fuzzy inference rules in order to achieve energy saving. In a simulation for controlling temperature, a thermal image is transformed to a color distribution image of $300{\times}400$ size to analyze the thermal image. A color distribution image is composed of R, G and B values haying temperature values of Red, Magenta, Yellow, Green, Cyan and Blue. Each color has a temperature value from $24.0^{\circ}C$ to $27.0^{\circ}C$ and a color distribution image is classified into height hierarchies from level 1 to level 10. The classified hierarchies have their peculiar color distributions and temperature values are assigned to each level by temperature values of the peculiar colors. The process for controlling overall balance of temperature and the direction of wind in an indoor space is as follows. Fuzzy membership functions are designed by the direction of wind, duration time, and temperature and height values of a color distribution image to calculate the strength of wind. After then, the strength of wind is calculated by membership values of membership functions.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.31 no.1
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• pp.52-70
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• 2018

Objectives : Atopic dermatitis(AD) and environmental factors are closely related, but there is lack of oriental medical examination. So we compared the relationship between AD and various environmental factors in Oriental medicine and Western medicine. Methods : We described the relationship between AD and environmental factors through the latest papers and a review of the oriental medicine literature. Results : The regional diversity of AD incidence implies a close relationship between climate factors and AD, and high altitude and low pH springs also have an effect on AD. Air pollutants from industrialization and urbanization aggravate AD. The increase in indoor residence time and the increase in room temperature and humidity have also increased the sensitization to allergens such as house dust mite. In oriental medicine, wind(風) is one of the environmental factors and is an inflammatory state due to external irritation. Wind-Humidity(風濕) refers to erythematous wetting dermatitis with itching and exudation, Wind-Fever(風熱) refers to acute inflammatory reaction with erythematous papules and plague, and Blood-Weakness(血虛) refers to aggravation and chronicization of inflammation due to persistence of skin barrier impairment. Conclusions : We examined the relationship between AD and various environmental factors. We also described the oriental medical viewpoints of the environmental factors in the occurrence of AD and skin barrier impairment.