• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E2
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• pp.53-59
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• 2001

A hybrid dust-collector combining electrostatic charging with fabric filtration method was developed, and its performance characteristics were evaluated in this study. Charged particles build porous dendritic structure on the surfaces of filter by electrostatic attraction, increasing the collection efficiency of dust particles and reducing the pressure drop through the deposited dust layer and filter media. The cleaning performance of the dust layer is improved because the dendritic structured dust layer can be removed more easily by pulse jet cleaning flow. The results of the experiment showed a reduction of fine particle emission of 37% and the energy saving of 13% by precharging dust particles before filtration.

• Journal of Environmental Impact Assessment
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• v.29 no.4
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• pp.286-297
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• 2020

This research studied human health risk assessment of PAHs (Polycyclic Aromatic Hydrocarbons) in road dust sediments collected from 6 sites in four different cities in Korea. PAHs are well known to be human carcinogens and toxic compounds that are commonly generated from incomplete combustion of fuels and energy products. Such compounds which is absorbed by atmospheric suspended dust can be emitted into air in gaseous form and often deposited on road dust sediments. The PAHs which is deposited on sediment particles can also be re-dispersed by vehicles or winds on the road surface. It can be harmful for humans when exposed via breathing, ingestion and dermal contact. This study examined human health risk assessment of PAHs in deposited road dust sediments. Results showed that the excess cancer risk estimates were above 1.0×10-6 at main traffic roads and resident area in Ulsan city. According to the result of deterministic risk assessment, dermal-contact was the major pathway, while the contribution of the risk from inhalation was less than 1%. The probabilistic risk assessment showed similar levels of cancer risk derived from the deterministic risk assessment. The result of sensitivity analysis reveal that exposure time is the most contributing factor (69%). Since the values of carcinogenic risk assessment were higher than 1.0 × 10^-6, further detailed monitoring and refined risk assessment for PAHs may be required to identify more reliable and potential cancer risks for those who live in the study locations in Ulsan city.

• Journal of Environmental Health Sciences
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• v.46 no.4
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• pp.398-409
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• 2020

Objectives: This study aimed to evaluate environmental exposure to tobacco-specific nitrosamines (TSNAs) by conducting an analysis of the concentration of TSNAs in deposited dust collected from a fertilizer plant and the surrounding village, a simulation of high-temperature drying of tobacco waste, and CALPUFF modeling. Methods: The raw materials of the products, deposited dust (inside and outside the plant and residential area), soil, and wastewater were sampled and the TSNA concentrations were analyzed by LC-MS/MS. As the plant was closed down before the investigation, simulation tests were conducted to confirm the substances discharged during high-temperature (300℃) drying of tobacco waste. CALPUFF modeling was performed to identify the area of influence due to exposure to TSNAs. Results: TSNAs were detected in organic fertilizers estimated to contain tobacco waste, deposited dust, and soil collected from inside and outside the plant. N'-nitrosonornicotine (NNN), 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), and N'-nitrosoanatabine (NAT) components were detected in five of 15 deposited dust samples collected from the residential area around the plant, while TSNAs were not detected in the five sampling points in the control area. Also, the simulation test for the high temperature drying of tobacco waste found emissions of TSNAs. The CALPUFF modeling results showed that the survey area was likely to be included in the area of influence of TSNA emissions from the plant. Conclusions: It is estimated that harmful tobacco ingredients such as TSNAs were dispersed in nearby areas due to the illegal use of tobacco waste as a raw material to produce organic fertilizers at the plant. These findings assume that the residents have been exposed to TSNAs and suggest that the need for the establishment of measures to manage environmental health.

• Journal of Environmental Science International
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• v.11 no.2
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• pp.111-120
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• 2002

Asian dust(or yellow sand) occurs mainly in spring and occasionally in winter in east Asia, when the weather conditions are under an upper trough/cut-off low and surface high/low pressure system during blocking episode days associated with the stationary patterns of the upper level jet stream. The transport mechanism for Asian dust during the blocking episode days in spring 2001 was analyzed using the TOMS aerosol index and meteorological mesoscale model 5(MM5). Based on the E vector, an extension of an Eliassen-Palm flux, the blocking episode days were found to be associated with the development of an upper cut-off low and surface cyclones. Concurrently, the occurrence of dust storms was also determined by strong cold advection at the rear of a jet streak, which exhibited a maximum wind speed within the upper jet stream. As such, the transport mechanism for Asian dust from China was due to advection of the isentropic potential vorticity(IPV) and isentropic surfaces associated with tropopause folding. The transport heights for Asian dust during the blocking episode days were found to be associated with the distribution of the isentropes below the IPV At the same time, lee waves propagated by topography affected the downward motion and blocking of Asian dust in China. The Asian dust transported from the dust source regions was deposited by fallout and rain-out with a reinforcing frontogenesis within a surface cyclone, as determined from satellite images using TOMS and GMS5. Accordingly, these results emphasize the importance of forecasting jet streaks, the IPV, and isentropes with geopotential heights in east Asia.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.110-120
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• 2005

For utilizing vitrification to treat low and intermediate level waste, industrial pilot plant was designed and constructed in October 1999 at Daejon, Korea through the joint research program among NETEC, MOBIS and SGN. More than 70 tests were performed on simulated IER, DAW etc. including key nuclide surrogate(Cs, Co); this plant has been shown to vitrify the target waste effectively and safely, however, some dust are generated from the HTF(High Temperature Filter) as a secondary waste. In case of long term operation, it is also concerned that pipe plugging can be occurred due to deposited dust in cooling pipe namely, connecting pipe between CCM(Cold Crucible Melter) and HTF. In this regard, we have developed the special complementary system of the off-gas treatment system to recycle the dust from HTF to CCM and to remove the interior dust of cooling pipe. Main concept of the dust recycling is to feed the dust to the CCM as a slurry state; this system is regarded as of an important position in the viewpoint of volume reduction, waste disposal cost and glass melt control in CCM. The role of DRS(Dust Recycling System) is to recycle the major glass components and key nuclides; this system is served to lower glass viscosity and increase waste solubility by recycling B, Na, Li components into glass melt and also to re-entrain and incorporate into glass melt like Cs, Co. Therefore dust recycling is helpful to control the molten glass; it is unnecessary to consider a separate dust treatment system like a cementation equipment. The effects of Dust Cleaner are to prevent the pipe plugging due to dust and to treat the deposited dust by raking the dust into CCM. During the pilot vitrification test, overall performance assessment was successfully performed; DRS and Dust Cleaner are found to be useful and effective for recycling the dust from HTF and also removing the dust in cooling pipe. The obtained operational data and operational experiences will be used as a basis of the commercial facility.

• Journal of Environmental Science International
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• v.9 no.6
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• pp.495-503
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• 2000

Dust samples were collected from 17 middle and high schools in the Jeonju-city. heavy metal concentrations were determined for the dry-deposited dusts from indoor and outdoor of classroom and playground of each sampling site. Concentrations of Cd, Cr, Cu, Ni, Pb and Zn in indoor\`s dusts were highly concentrated. Also heavy metal concentrations in outdoor\`s dusts were similar to that of indoor\`s dusts. Concentrations of Cd, Cu, and Zn in the dusts were much higher than the world average contents in soil and environmental orientation value. These levels are similar to those of the dust samples at middle schools located at Kangseo-gu and Yangchon-gu , Seoul. Playground dusts in 6 schools exhibited the enhanced heavy metal pollution with a pollution index (by Kloke) greater than 1.0. Most indoor and outdoor dusts exhibited the enhanced heavy metal pollution with a pollution index(by Cullbard et al.) greater than 1.0.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.705-713
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• 2016

This study investigates the concentration sudden rise in fine particle according to resuspended dust from paved roads after sudden heavy rain in Busan on August 25, 2015. The localized torrential rainfall in Busan area occurred as tropical airmass flow from the south and polar airmass flow from north merged. Orographic effect of Mt. Geumjeong enforced rainfall and it amounted to maximum 80 mm/hr at Dongrae and Geumjeong region in Busan. This heavy rain induced flood and landslide in Busan and the nearby areas. The sudden heavy rain moved soil and gravel from mountainous region, which deposited on paved roads and near roadside. These matters on road suspended by an automobile transit, and increased fine particle concentration of air. In addition outdoor fine particle of high concentration flowed in indoor by shoes, cloths and air circulation.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.229-236
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• 2022

An experimental investigation was conducted on the influences of median size, dust concentration, dust condition (cloud and layer) for the fire and explosion hazard assessment of dusts with the same powder property. For this purpose, tests have been performed in accordance with 20 L explosion sphere, thermogravi- metric analyze, combustion rate tester (UN method). We investigated the explosion characteristics and flame propagation velocity (FPV) in dust cloud and the flame spread velocity(FSV) over dust layer on 8 dust samples with different particle sizes of 4 types of dusts (Sugar, Mg, Al, Zr). An explosion hazard increased with decreasing particle size in Mg and Al dust clouds, but sugar did not show the effect of explosion hazard due to particle size change in dust clouds. The flame propagation velocity (FPV) of suspended dusts increased significantly when the particle size decreased from micro to nano than the variation of particle size in micro range. The flame spread velocity (FSV) over dust layer showed a tendency to increase over the inclined dust layers (30° slope) rather than the horizontal dust layers (0° slope). The flame spread rate (FSV) over dust layers increased on the inclined dust layer (30° slope) rather than the horizontal dust layer (0° slope) and was higher upward flame than the downward flame in condition of inclined dust layers(30° slope).

• Asian Journal of Atmospheric Environment
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• v.10 no.3
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• pp.162-167
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• 2016

This study was conducted in an industrial city (Bilaspur) representative of subtropical area in central India. In order to assess the metal deposition on plant, concentrations of six target metals (i.e., Fe, Mn, Pb, Cu, Cd, and Cr) in both plant leaf and dust (deposited on its surface) samples were measured from six different sites. Metal concentrations in dust samples were found on the order of Fe>Mn> Cr>Pb>Cu>Cd. In contrast, the concentration of metals in plant leaves were seen on the order of Fe>Mn>Cr>Cd>Cu>Pb. As such, Cd showed significantly high concentration in leaves relative to their corresponding dust samples. A high accumulation potential for Fe and Cd was seen from Butea monosperma, while Mn and Pb were accumulated noticeably in Pongamia pinnata and Butea monosperma. Likewise, Cr and Cu were enriched in Calotropis procera, Alstonia scholaris, and Butea monosperma. The overall results of our study suggest that the foliar uptake pattern should vary considerably by an interactive role between plant and metal types.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.126-132
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• 2009

Automotive heat exchangers use louver fins for their high efficiency. However, the efficiency can significantly drop for constructional vehicles or heavy equipments due to dust deposited on the louver fins with narrow slits. Thus it is necessary to develop new fins that lead to less fouling, so that a better performance can be achieved after exposure to a dusty environment over long period of time. New wavy fins were considered in the study and numerically analysed to compare with louver fins in the areas of air-side pressure drop, heat release rate, and particulate deposition. In addition, an experiment was done on the pressure drop and the particulate deposition. The results showed that the wavy fins would be a better choice for long-term use due to the excellent dust-proof performance in comparison to louver fins, in spite of the initial inferior performance of heat release.