• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.74-81
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• 2020

As of 2020, due to the influence of fine dust from China and domestic dust, the cloudy sky of Korea has become a daily routine not only in spring but also in autumn/winter. In 2013, the International Cancer Institute under the World Health Organization designated fine dust as a group 1 carcinogen that has been confirmed to be carcinogenic to humans. The purpose of this study is to theoretically review 5 fine dust-related design studies, by analyzing the case of three types of wearable air purifiers on the market, it is to propose an improved open wearable air purifier. As a verification method, a working prototype was produced to measure the amount of fine dust reduction. Therefore, this study derived three design insights of wearable air cleaner through case analysis. First, it maximizes openness by minimizing the area touching the face. Second, the nozzle where the air comes out should be close to the respiratory organ. Third, position of the motor is to be as far away as possible from the ear considering the noise. Based on this, I suggested an open-type wearable air purifier design that maximizes the user openness and improves the wearing comfort. I hope that it will be an opportunity to increase the coverage of wearable air cleaner and protect the respiratory health of users.

• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.369-379
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• 2015

Objectives: The lack of reliable information on environmental pollution and health impacts related to asbestos contamination from abandoned mines has drawn attention to the need for a community health study. This study was performed to evaluate asbestos-related health symptoms among residents near abandoned asbestos mines located in the Chungcheong Provinces. In addition, exposure assessment for asbestos is needed although the exposure to asbestos was in the past. Methods: Past exposure to asbestos among inhabitants near abandoned asbestos mines was estimated by using surface sampling of deposited dust in indoor and outdoor residences. A total of 54 participants were divided into two groups with (34 cases) and without (20 controls) diseases related to asbestos. Surface sampling of deposited dust was carried out in indoor and outdoor residences by collecting 105 samples. Deposited dust for sampling was analyzed by polarization microscope (PLM) and scanning electron microscope?energy dispersive x-ray spectrometer (SEM-EDX) to detect asbestos. Subsequently, the elements of the deposited dust with asbestos were analyzed by SEM-EDX to assess the contribution of sources such as abandoned mines, slate and soil. Results: Among the 105 samples, asbestos was detected by PLM in 29 (27.6%) sampling points, and detected by SEM in 56 (48.6%) sampling points. Asbestos in indoor residences was detected by PLM in four sampling points, and by SEM in 12 sampling points. Asbestos detection in indoor residences may be due to ventilation between indoors and outdoors, and indicates long-term exposure. The asbestos detection rate for outdoor residences in the case group was higher than that in the control group. This can be explained as the case group having had higher exposure to asbestos, and there has been continuous exposure to asbestos in the control group as well as the case group. Conclusion: Past residential asbestos exposure may be associated with asbestosis among local residents near abandoned asbestos mines. Odds ratios were calculated for asbestos detection in outdoor residence by logistic regression analysis. Odds ratio between asbestos detection and asbestosis pulmonum was 3.36 (95% CI 0.90-12.53) (p=0.072), adjusting for age, sex, smoking status and work history with multi-variable logistic regression by PLM analysis method.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.119-129
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• 2005

The ambient TSP data measured at Seoul, Incheon. Taean, Daegu, Busan in Korea were used to explain the chemical composition and general features of Asian Dust (AD) observed in Korea. 9 episodes out of 19 were sampled from 2000 through May 2002, and measurements were conducted covering ionic and metal components with mass concentration. The results showed that daily averaged mass concentration (TSP) during the AD episodes was 458 $\mu\textrm{g}$/㎥, and ionic and metal concentrations were 27.93 $\mu\textrm{g}$/㎥ and 71.7 $\mu\textrm{g}$/㎥, respectively, accounting for 6.1 % and 15.5% of the total aerosol mass. TSP concentrations during episodes were varied from 120 to 1742 $\mu\textrm{g}$/㎥ according to the impact of Asian Dusts and had a tendency of showing higher values at sites in the west side of Korea, which can be explained by the effect of diffusion and deposition. In this study, ionic components like Ca (NO$_3$)$_2$, CaSO$_4$, NaNO$_3$, Na$_2$SO$_4$ were prominent types in secondary aerosol during AD periods and also indicated that V, Co as well as soil elements such as Ca, Fe, Mg, Mn, K correlated well with Al, while Cu, Cd, Pb, Zn didn't agree well with it. In addition, enrichment factors (EFs) for each metal component were obtained to provide simple information about source contribution of Asian Dust, and the results were compared with those from other AD studies. In this study, the results showed that aerosol properties in Korea during the Asian Dust were considerably different from those of general atmospheric condition and specially varied from case to case rather than site to site, which implies that there are certain variations in the soil of source region, pathways of air mass, and meteorological condition. For the enhanced study, those factors should be combined with the features of Asian Dust resolved from this study.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.97-104
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• 2007

This study was carried out to develop the modified cyclone dust collector in windowless broiler building measuring 12 m wide, 46 m long, with a side wall height of 3 m and a capacity of 12,800 birds. Ventilation rate in windowless broiler building was $0.014{\sim}0.015\;and\;0.158{\sim}0.181cmm$ in second weeks and fifth weeks of age, respectively. Ammonia concentration was $13{\sim}16\;and\;20{\sim}24\;ppm$ in first and second weeks of age, respectively. Amount of dust collected in dust collector each week was 104.1, 274.7 and 388.6g in first, second and third weeks of age. But it was decreased from fourth weeks of age because of the increased ventilation rate. Total suspended particulate(TSP) of polluted air was $3,111.7{\sim}8,745.2{\mu}g/m^3$, but it was decreased to $530.8{\sim}2,264.4{\mu}g/m^3$ when it passed through the dust collector. Collecting efficiency was $54.2{\sim}82.9%$ in TSP. But collecting efficiency of Particulate matter smaller than $1{\mu}g$ (PM1.0) was $7.6{\sim}33.8%$, and lower than TSP. TSP concentration in control broiler house was 1,387.6 and $4,210.1{\mu}g/m^3$ in first and fourth weeks of age, respectively. But it was decreased to 876.3 and $2,535.3{\mu}g/m^3$ in broiler house operated dust collector in first and fourth weeks of age, respectively. Dust collecting efficiency for TSP was $36.8{\sim}39.8%$, and it was decreased to $11.4{\sim}39.8%$ in smaller dust size.

• Journal of Environmental Science International
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• v.23 no.12
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• pp.2045-2056
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• 2014

In this study, pressure drop was measured in the pulse jet bag filter without venturi on which 16 numbers of filter bags (Ø$140{\times}850{\ell}$) are installed according to operation condition(filtration velocity, inlet dust concentration, pulse pressure, and pulse interval) using coke dust from steel mill. The obtained 180 pressure drop test data were used to predict pressure drop with multiple regression model so that pressure drop data can be used for effective operation condition and as basic data for economical design. The prediction results showed that when filtration velocity was increased by 1%, pressure drop was increased by 2.2% which indicated that filtration velocity among operation condition was attributed on the pressure drop the most. Pressure was dropped by 1.53% when pulse pressure was increased by 1% which also confirmed that pulse pressure was the major factor affecting on the pressure drop next to filtration velocity. Meanwhile, pressure drops were found increased by 0.3% and 0.37%, respectively when inlet dust concentration and pulse interval were increased by 1% implying that the effects of inlet dust concentration and pulse interval were less as compared with those changes of filtration velocity and pulse pressure. Therefore, the larger effect on the pressure drop the pulse jet bag filter was found in the order of filtration velocity($V_f$), pulse pressure($P_p$), inlet dust concentration($C_i$), pulse interval($P_i$). Also, the prediction result of filtration velocity, inlet dust concentration, pulse pressure, and pulse interval which showed the largest effect on the pressure drop indicated that stable operation can be executed with filtration velocity less than 1.5 m/min and inlet dust concentration less than $4g/m^3$. However, it was regarded that pulse pressure and pulse interval need to be adjusted when inlet dust concentration is higher than $4g/m^3$. When filtration velocity and pulse pressure were examined, operation was possible regardless of changes in pulse pressure if filtration velocity was at 1.5 m/min. If filtration velocity was increased to 2 m/min. operation would be possible only when pulse pressure was set at higher than $5.8kgf/cm^2$. Also, the prediction result of pressure drop with filtration velocity and pulse interval showed that operation with pulse interval less than 50 sec. should be carried out under filtration velocity at 1.5 m/min. While, pulse interval should be set at lower than 11 sec. if filtration velocity was set at 2 m/min. Under the conditions of filtration velocity lower than 1 m/min and high pulse pressure higher than $7kgf/cm^2$, though pressure drop would be less, in this case, economic feasibility would be low due to increased in installation and operation cost since scale of dust collection equipment becomes larger and life of filtration bag becomes shortened due to high pulse pressure.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.340-350
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• 2020

A rapid refresh wave forecasting system has been developed using the sea wind on the Korea Local Analysis and Prediction System. We carried out a numerical experiment for wind-wave interaction as an important parameter in determining the forecasting performance. The simulation results based on the seasons of with typhoon and without typhoon has been compared with the observation of the ocean data buoy to verify the forecasting performance. In case of without typhoon, there was an underestimate of overall forecasting tendency, and it confirmed that an increase in the wind-wave interaction parameter leads to a decrease in the underestimate tendency and root mean square error (RMSE). As a result of typhoon season by applying the experiment condition with minimum RMSE on without typhoon, the forecasting error has increased in comparison with the result without typhoon season. It means that the wave model has considered the influence of the wind forcing on a relatively weak period on without typhoon, therefore, it might be that the wave model has not sufficiently reflected the nonlinear effect and the wave energy dissipation due to the strong wind forcing.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.80-85
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• 2008

Catalytic filter is capable of performing shallow bed dust filtration plus a catalytic reaction, promoted by a catalyst deposited in its inner structure. Such a feature may allow potential cost and space reduction in several environmental applications. Dust filtration and halogenated volatile organic compound (1,2-dichlorobenzene) destruction were carried out in a lab-scale reactor. $WO_3-V_2O_5/TiO_2$ supplied by MaGreen, which showed high catalytic acitivity at low temperature, was used as a catalyst. P-84 that can be operated under $250^{\circ}C$ was used as a felt. The catalytic activity and filtration efficiency of catalytic filters were investigated under the operating conditions, including temperature, face velocity, and dust concentration. The catalytic activity of catalytic filter increased with increasing temperature and the amount of catalyst loaded. The test results showed that the filtration efficiency was primarily affected by the face velocity. Pressure drop variations as a function of time were investigated for a variety of conditions. In case of virgin filter, a dramatic decrease in the pulse interval and a slightly increase in the base line pressure drop were observed. A relatively slow pressure drop build-up was recorded for the catalytic filter due to smooth and slippery surface characteristics of nanofiber. The catalytic filter indicated that high filtration efficiency over 99.98% and high catalytic activity over 90% at 1 m/min and $210^{\circ}C$.

• Applied Biological Chemistry
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• v.2
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• pp.45-52
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• 1961

The decomposition of malathion in dust for mulations prepared from four Korean tales as carriers during storage period has been studied. Amberlite CG-120, a cation exchange resin . which has higher cation exchange capacity than tales, was also used as a carrier in hope of finding out the effect of nagative charge upon the decomposition of malathion. Besides the original talc powders obtained directly from the mines, the hydrogen ion saturated forms were also used as carriers for comparisonal study. The saturated ions for the resin were hydrogen, sodium and magnesium. As the physical properties of the tales, colloid content, water adsorption capacity, PH, specific surface, phosphate fixing capacity and exchangeable canons were determined, and these properties were correlated with the amount of the decomposition. Following results were obtained from the experiment. 1. The malathion in the talc in dust was found to decompose around 10-15% ofthe total withina month. About 50% of the decom position that took place after a month was found to occur within a week. 2. The resin which has higher cation exchange capacity than the tales was highly effective in the decomposition of malathion compared with the tales. 3. In every case the saturation of the exchange complexes with hydrogen ion greatly accelerated the decomposition of malathion. 4. The most highly correlated physical properties with the decomposition were colloid content and specific surface of the tales. 5. The water adsorption and phosphate fixing capacities of the tales were found not to correlate with the amount of malathion decomposed. From the experimental results it was concluded that the active negative spots on the colloidal tales or the resin attract the electropositive phosphorus atom in a malathion molecule thereby inducing the decomposition easier. The presence of hydrogen ion nearby might cause a catalytic effect in the decomposition of malathion.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.409-414
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• 1998

To examine the detectability of the aerosol and/or Yellow dust from China crossing over the Yellow sea, three works carried out as follows , Firstly, a comparison was made of the visible(VIS), water vapor(WV), and Infrared(IR) images of the GMS-5 and NOAA/AVHRR on the cases of yellow sand event over Korea. Secondly, the spectral radiance and reflectance(%) was observed during the yellow sand phenomena on April, 1998 in Seoul using the GER-2600 spectroradiometer, which observed the reflected radiance from 350 to 2500 nm in the atmosphere. We selected the optimum wavelength for detecting of the yellow sand from this observation, considering the effects of atmospheric absorption. Finally, the atmospheric radiance emerging from the LOWTRAN-7 radiative transfer model was simulated with and without yellow sand, where we used the estimated aerosol column optical depth ($\tau$ 673 nm) in the Meteorological Research Institute and the d'Almeida's statistical atmospheric aerosol radiative characteristics. The image analysis showed that it was very difficult to detect the yellow sand region only by the image processing because the albedo characteristics of the sand vary irregularly according to the density, size, components and depth of the yellow sand clouds. We found that the 670-680 nm band was useful to simulate aerosol characteristics considering the absorption band from the radiance observation. We are now processing the simulation of atmospheric radiance distribution in the range of 400-900 nm. The purpose of this study is to present the preliminary results of the aerosol and/or Yellow dust detectability using the Ocean Scanning Multispectral Imager(OSMI), which will be mounted on KOMPSAT-1 as the ocean color monitoring sensor with the range of 400-900 nm wavelength.

• Resources Recycling
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• v.13 no.1
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• pp.22-27
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• 2004

Purification on the leaching solution of the crude zinc oxide obtained by the reduction of EAF dust has been carried out. Pb and Cd ions in the leaching solution were precipitated and removed from the solution by the addition of zinc metal powder. The purification condition for electrowinning to obtain the high purity zinc metal was investigated by analyzing the effects of Pb and Cd ion concentrations on the contents of impurities in the recovered zinc metal. The 3 N purity zinc metal was obtained at the electrolysis condition of the concentrations of Pb less than 2 ppm and Cd less than 0.1 ppm in the purified solution. For this purification, the amounts of zinc metal powder more than 8.5 g/l should be added in the crude zinc oxide leached solution.