• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.749-755
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• 2013

The purposes of this research are to know the optimal gab and electric pressure (voltage) of electrode-plates coated with activated carbon and also to study their arrangement through dust removal efficiency. From the experimental results of attached dust mass at different electrode-plate gab, the frequency of attachment and detachment of dust was more increased as electrode-plate gab was closer. In attached dust mass per unit area of electrode-plate, the farther electrode gab, the more increased. But in total attached dust mass, the closer electrode gab, the more removed. From the experimental results, the optimal electrode arrangement in dust removal chamber was considered that the forward parts of chamber need to be increased the number of electrode-plate, the backward parts to be increased them. The dust attachment have no relation with electric pressure while showing high removal efficiency under condition of 5 kV of voltage and 2 cm of electrode-plates gab.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.532-541
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• 2022

Purpose: The purpose of this study is to suggest that the existing power demand prediction method including power demand according to fine dust is included in the existing power consumption by using an air purifier to improve the air quality due to fine dust. Method: The method of the study was compared and analyzed using data on the concentration of fine dust in Seoul for three years, household power consumption, and climate observation, and the effect of fine dust on power consumption in Seoul was identified in April and October. Result: The power consumption of home air purifiers in Seoul due to fine dust differences between April and October was calculated to be 2,141 MWh, accounting for 3.4% of the total difference in the use of home appliances in April and October. Conclusion: The effect of fine dust on household power consumption was verified, and power demand prediction is essential for economic system operation and stable power supply, so power consumption due to fine dust should be considered as well as focusing on power consumption of existing air conditioners and heaters.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.3
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• pp.21-28
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• 2022

Fine dust enters the lungs or blood vessels through the respiratory tract through the air. Recently, due to the fine dust problem, the demand for air purifiers in Korea is also increasing rapidly. Moss is the oldest terrestrial plant, and it is known that it has the property of adsorbing and decomposing heavy metals and fine dust. To compare the effect of reducing fine dust between moss and the existing chemical filter (Hepa), a cube of 1 m³ was manufactured and the amount of fine dust reduction under a controlled environment was compared. Under the fine dust conditions, an umbrella moss filter, rat tail moss filter, feather moss filter, and silk moss filter were inserted for a total of 40 experiments, 10 times each in 4 different situations. The difference between the amount after 30 minutes was statistically significant for all filters. However, as a result of the test, it was confirmed that there was no statistically significant difference between filters for fine dust, mixed gas, CO₂, and O₂. In particular, it was confirmed that the previously claimed effect of oxygen generation was almost nonexistent. Through this result, it was confirmed that the reduction of fine dust is effective regardless of the species view of moss, and it is expected to replace or supplement the chemical filter of the existing air purifier through future improvement.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.223-238
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• 2015

The $PM_{2.1}$ was collected by LVCI (low volume cascade impactor) during Group-A Period (September 1990 to December 2012) and the $PM_{2.5}$ was collected by HVAS (high volume air sampler) during Group-B Period (September 2009 to April 2012) at Kyung Hee University, Global Campus located on the boarder of Yongin and Suwon. The 8 water-soluble ions ($Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $ NO_3{^-}$, and $SO_4{^{2-}}$) were analyzed by IC, and the 14 inorganic elements (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, Zn, Ti, Ag) were analyzed by XRF and ICP-AES after performing proper pre-treatments of each sample filter. The average total mass fractions of $SO_4{^{2-}}$, $NO_3{^-}$, and $NH_4{^+}$+ to $PM_{2.5}$ samples during Group-B Period were 0.39 in normal days, 0.44 in haze days, and 0.27 in Asian dust days, respectively; however, the average total mass fractions of Al, Fe, and Si to $PM_{2.5}$ mass were 0.043 in normal days, 0.021 in haze days, and 0.036 in Asian dust days, respectively. Especially the concentration of Pb was significantly decreased during Group-B Period rather than during Group-A Period, while Cr and Ni was increased during Group-B Period. In this study, we intensively compared the annual and seasonal patterns of major chemical species among normal days, haze days, and Asian dust days. Further we developed mass fraction profiles by collecting episode cases of haze days and Asian dust days, which were consisting of 22 chemical species. Those profiles are considered to be useful when applying various receptor models and establishing air quality management plans near future.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.11-19
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• 2002

The seasonal variation of $^7Be$ and $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout collected at Daejeon during the period of 1998 - 1999 has been studied. The annual mean values of 7Be concentrations in airborne dust, precipitation and dry fallout were in the range of $3.80{\sim}4.29\;mBq\;m^{-3},\;1.25{\sim}1.67\;Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$, respectively. The annual mean values of $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout ranged $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66 mBq\;l^{-1}\;\;0.036{\sim}0.0455\;MBq\;km^{-2}$, respectively. While the concentrations of $^7Be$ and $^{137}Cs$ in airborne dust and dry fallout were relatively higher in the spring and autumn when the amount of dry fallout increased than in other season, their concentrations in precipitation were relatively lower in the summer when the rainfall increased. The total depositions of $^7Be$ and $^{137}Cs$ due to dry fallout and precipitation were in the range of $80.7{\sim}137MBq\;km^{-2}$ and $0.059{\sim}0.060MBq\;km^{-2}$, respectively. More than 80% of $^7Be$ deposition resulted from precipitation, whereas about 60% of $^{137}Cs$ deposition was due to dry fallout.

• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.9-17
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• 1997

During the period of 1933-1994, house dusts were collected from 65 homes at 10 different localities by operating electric vacuum cleaners. House dust mites were isolated from 10 g dust by applying the modified wet sieving method. Total 7,257 mites were collected and 23 species were identified. Among them, Demctophqgoines loyinaf (DF) was predominant (65. Soy) of the total) , followed by D. pteronvssinus (DP) (20.6%) and Tyrophagus nutrescentios (TP) (6.5%) . Rhizoglvphur robini, Sancqsscnin phvIlophogiann, Cheyletus trcussarti and Scheloribates latipes were the first findings from Korea. DF was predominant in Seoul (66.8%), Kwangju (63.6%), inland of Pusan (79.6%1, Inchon (96.5%), Taejon (83.9%), Chouju (87.15) and Chongiu (95.2%), whereas DP was predominant in Yongkwang-ub (72.5%) and Yongdo (island) of Pusan (64.9%), and TP in Chunchon (38.2%) The localities where DP and TP were predominant showed higher relative humidity in air (> 73% RH) . Among 62 study homes, DF, DP and TP were found in 24.6% of the homes, co-habitat of two species in 48.1% and one species in 27.3%. DF was predominant in 63.5% of the homes studied, DP in 29.6% and TP in 6.9%. In 10 g of the house dust, less than 99 mites were found in 49 homes (70.0%), 100-499 mites in 11 homes (15.7%), 500-999 mites in 3 homes (4.3%) and more than 1,000 mites in 2 homes (2.9%). No mite was found in 5 homes (7.1%). In order to evaluate environmental factors affecting the population density of house dust mites, house type, age of house construction, size of the house, number of the family and frequency of the cleaning were compared with the number of mites, and none of the above factors were statistically correlated with the mite density.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.751-762
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• 2015

This study was performed to investigate the stability of soil moisture in controlling air ventilation rate within a horizontal biofilter, and to compare removal efficiency (RE) of indoor air pollutants including fine dust, volatile organic compounds (VOCs), and formaldehyde (HCHO), depending on whether dieffenbachias (Diffenbachia amoena) were planted in the biofilter. The relative humidity, air temperature, and soil moisture contents showed stable values, regardless of the presence of D. amoena, and the plants grew normally in the biofilter. REs for number of fine dust particles (PM10 and PM2.5) within the biofilter filled with only soil were at least 30% and 2%, respectively. REs for number of fine dust particles (PM10 and PM2.5) within the biofilter including the plants were above 40% and 4%, respectively. RE for fine dust (PM10) weight was above 4% and 20%, respectively, in the biofilter containing only soil or soil together with plants. In the case of the biofilter filled with only soil, REs for xylene, ethylbenzene, toluene or total VOC (T-VOC) were each more than 63%; however, REs for benzene and formaldehyde (HCHO) were above 22% and 38%, respectively. In the biofilter with the plants, REs for xylene, ethylbenzene, toluene, and T-VOC were each above 72%, and REs for benzene and HCHO were above 39%. Thus, RE of the biofilter integrated with plants was found to be higher for volatile organic compounds than for fine dust. Hence, the biofilter was very effective for indoor air quality improvement and the effect was higher when integrated with plants.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.347-352
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• 2012

Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshifts. The AKARI performed an all sky survey in 6 IR bands (9, 18, 65, 90, 140, and $160{\mu}m$) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can measure the total infrared luminosity ($L_{TIR}$) of individual galaxies much more precisely, and thus, the total infrared luminosity density of the local Universe. In the AKARI NEP deep field, we construct restframe $8{\mu}m$, $12{\mu}m$, and total infrared (TIR) luminosity functions (LFs) at 0.15 < z < 2.2 using 4,128 infrared sources. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and $24{\mu}m$) by the AKARI satellite allows us to estimate restframe $8{\mu}m$ and $12{\mu}m$ luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from z = 0 to z = 2.2, all probed by the AKARI satellite.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.362-371
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• 2012

Objective of this research was to secure the information on physical and chemical properties of peatmoss and coir dust. To achieve this, 6 kinds of peatmoss and 10 kinds of coir dust currently used in the country as the root medium components in plant factories were collected and analysed. The mean ${\pm}$ standard deviation (SD) of total porosity and container capacity in peatmoss and coir dust were $79.6{\pm}5.04$ and $83.6{\pm}6.18%$, and $69.9{\pm}10.17$ and $65.9{\pm}3.46%$, respectively. These indicate that peatmoss has higher water holding capacity than coir dust and the characteristics are highly varied among peatmoss. The 4 out of 5 kinds of peatmoss had lower than 10%, but coir dust had 12~26%, of air-filled porosity. The percentage of easily available water and buffering water in peatmoss and coir dust was 18~22 and 11~16% and 9~13 and 5.5~7.5%, respectively. These results indicate that precise irrigation is required when coir dust is used as the root medium. The ranges of pH and electrical conductivity (EC) were 3.46~4.17 and $0.137{\sim}0.253dS{\cdot}m^{-1}$ in peatmoss and 5.31~6.48 and $0.250{\sim}0.1.580dS{\cdot}m^{-1}$ in coir dust. However, $0.563{\pm}0.83dS{\cdot}m^{-1}$ in mean ${\pm}$SD of coir dust EC indicates that it is higher than that of peatmoss, and the coir dust are highly varied in EC. The cation exchange capacity of peatmoss was 3 to 4 times as high as that of coir dust. The coir dust had higher $NO_3$ and $PO_4$ and lower $NH_4$ than peatmoss. The K and Na concentrations in coir dust were extremely high indicating that these ions caused the rising in EC. The percentage of hot water and alkali extracts of peatmoss were 6.67~16.37 and 0~38%, whereas those of coir dust were 30.0~65.1 and 23.1~70.3%. These results mean that possible existence of growth inhibiting materials in coir dust.

• The Journal of Sustainable Design and Educational Environment Research
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• v.6 no.2
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• pp.66-90
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• 2007

The purpose of this study is to measure and analyze primary causes of indoor air pollution, including carbon dioxide, minute dust, and total volatile organic compounds, for each room before the beginning of a class through the time of discharge after the end of the class in general classrooms, computer rooms, and science rooms of three newly-established schools that opened in 2006, examine properties of indoor air environment in each room by educational activities at school, and determine effective management schemes; the results of this study can be summarized as follows: 1) As for implications for each item found in the mean for each place, since minute dust (PM10) was more likely to occur in time slots full of students' activities, such as a traveling class and a recess, than in the middle of a class and could be expected fully, it is necessary to make a scheme for cleaning in order to reduce minute dust within a room, for example, by usually using a vacuum cleaner indoors. 2) While carbon dioxide was expected to vary with the differences in the amount of breath between higher-graders and lower-graders in a general classroom but showed insignificant difference by grades, showing differences in pollution by four times at a maximum according to the opening of a window as expected, it is necessary to implement artificial or natural ventilation and take a positive measure, for example, by presenting a concrete ventilation scheme, in order to improve indoor air pollution at a room practice. 3) Total volatile organic compounds were found to exceed the standard by more than twice in general classrooms, science rooms, and computer rooms of the schools because of building materials, furnitures including desks and chairs, panels and boards for environment beautification, and items which could be detected even from students' clothes; while a field directly-reading tool was used, obtaining high reliability for the results, it is necessary to apply an analytical method based on process test separately for actual correct measurement if a significantly great amount of total volatile organic compounds appear as compared with other schools due to measuring expenses and consecutive measurements. 4) Since formaldehyde (HCHO) was generally found to exceed the standard in general classrooms, science rooms, and computer rooms, it is necessary to establish and operate a ventilator during a class in a computer room which requires airtightness and a science room in which an organic compound should be used for a class.