• Journal of the Korean earth science society
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• v.27 no.1
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• pp.73-82
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• 2006

Dust samples were collected from 10 middle and high schools in the Gochang-Gun, Korea. 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, Cu, Pb and Zn in indoor's dusts were highly concentrated. Also concentrations of Cu, Ni, Pb and Zn in outdoor's dusts were highly concentrated. 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 and high schools located in Jeonju-city, Korea. Compared with concentrations of heavy metals in soils and dusts in Korea, the environment of indoor and outdoor of classroom is highly concentrated except for Cu, Zn. The concentrations of playground is less than that of residential dust and main road dust and playground in Jeonju-city. Playground dusts in 1 school exhibited the enhanced heavy metal pollution with a pollution index (Kloke, 1979) greater than 1.0, but indoor and outdoor dusts in 7 schools exhibited the enhanced heavy metal pollution with a pollution index (by Kloke) yester than 1.0.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.1
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• pp.24-34
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• 2015

Domestic companies supplying electricity must increase obligatory duty to use renewable energy annually. If not met with obligatory allotment, the electricity-supply companies must pay RPS (Renewable Portfolio Standards) penalty. Although the power plants using a pulverizing coal firing boiler could co-fire up to around 3 per cent with wood pellets mixed in with coal feedstock without any major equipment revamps, they recorded only about 60 per cent fulfillment of RPS. Consequently, USD 46 million of RPS penalty was imposed on the six power supplying subsidiaries of GENCOs in 2014. One of the solutions to reduce the RPS penalty is that the power supply companies adopt the co-firing of torrefied lignocellulosic biomass in coal plants, which may contribute to the use of over 30 per cent of torrefied biomass mixed with bituminous coals. Extra binder was required to form pellets using torrefied biomass such as wood chips, PKS (Palm Kernel Shell) and EFB (Empty Fruit Bunch). Instead of corn starch, 30, 50 and 70 per cent of Larix saw dusts were respectively added to the torrefied feedstocks such as Pinus densiflora chips, PKS and EFB. The addition of saw dusts led to the decrease of the calorific values of the pellets but the forming ability of the pelletizer was exceedingly improved. Another advantage from the addition of saw dusts stemmed from the reduction of ash contents of the pellets. Finally, it was confirmed that torrefied oil palm biomass such as PKS and EFB could be valuable feedstocks in making pellets through improved binding ability.

• Journal of Conservation Science
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• v.35 no.3
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• pp.227-235
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• 2019

In Korea, various methods are applied to prevent wooden structures from being damaged by termites. However, since there is no way to quickly bring toxic substances in contact with the termites inside the timber, it leads to the damage of wooden cultural property due to the prolonged period of controlling the termites. Accordingly, an indoor evaluation criteria study was conducted for the introduction of powder-type termiticides in Korea, which produced rapid control effects by drilling wood and directly contacting and transferring toxic substances inside the timber. First, contact toxicity and transfer ability of termite dusts were evaluated to establish the criteria for evaluation of effectiveness against Reticulitermes speratus. The contact toxicity confirmed 100% mortality of fipronil, deltamethrin and cyfluthrin termite dusts within 24 h of contact; however, differences occurred in the active ingredient transfer time to the sublethal. In addition, in the case of transfer ability evaluation, the rate of mortality gradually decreased under 1:9 and 1:25 ratio conditions; however, the difference in the reduction rate was identified depending on the type of termite dust. the results of the evaluation of compressive strength of the wood showed that the difference in the measured values between the control group and the conditions of perforation 1 to 3 times, which does not significantly affect the compressive strength of wood. In this study, the criteria of termite dust selection and evaluation method of dust-type termiticides were presented and the applicability of the method was identified.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.456-461
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• 2012

To verify the utilization of biomass as energy, the combustion characteristic has been studied by an experimental combustion furnace under an isothermal and non-isothermal combustion. The wood pellet, rice straw and rice husk were used as biomass samples in this work. The characteristics of emission gases, dusts and residues from biomass combustion have been analyzed and compared with those of reuse derived fuel (RDF). From isothermal combustion experiments, it was found that the incomplete combustion of rice straw was greater that that of rice husk, wood pellet and RDF. This is due to the fact that the combustion reaction rate of the rice straw was faster than that of other samples, and the oxygen concentration in rice straw combustion was rapidly decreasing. It was also found that $NO_{X}$ concentration of emission gas from wood pellet combustion was the lowest. From non-isothermal combustion experiments, it was found that all samples were burned before $900^{\circ}C$. Also, the temperature range of $NO_{X}$ emission was similar to that of CO emission, on the other hand, $SO_{2}$ was emitted at a higher temperature than that of CO emission.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.56-57
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• 2019

Recently, the risk of fine dust is emerging in Korea. According to the OECD report, the incidence of hospitalization and mortality from lung disease is increased, and the incidence of lung cancer and mortality from ischemic heart disease with prolonged exposure are increased. In addition, indoor air quality has become an important factor affecting the human body as indoor life has increased due to the Industrial Revolution. Air pollutants that cause indoor air deterioration typically include particulate dusts as described above, formaldehyde and VOCs released in gaseous form from adhesive wood products used in building materials and furniture. May cause breathing problems. In this study, we analyzed the properties of adsorption matrix for improving indoor air quality using cork.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.2
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• pp.68-77
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• 2000

This study was performed to evaluate tannin exposure by wooddusts for workers in furniture factories and to investigate the relationship between tannin exposure and sino-nasal cancer risk. In order to explore possible cytological changes leading to nasal cancer, we have examined 50 male furniture workers and 50 matched controls using brush cytology. The results we have obtained in this study were as follows: 1. The tannin contents of woods used in woodworking factories have been measured and varied from 0.43 to 8.72 mg tannic acid equivalent per gram wood, for reconstituted softwood and turpentine (Syncarpia glomuliferia) respectively. 2. Airborne tannins in wooddusts were also determined by area and personal exposure. The values of mean exposures for both methods are ranged from 3.1 to $5.0{\mu}g/m^3$ and from 4.6 to $14.5{\mu}g/m^3$ in furniture manufactures. 3. Over nasal cytology scores 2, the scores of study group were slightly more than control group and this kind of metaplasias seemed to be occurred over $2mg/m^3$ wooddust and $6{\mu}g/m^3$ tannin exposure. Keratinising squamous metaplasia was investigated at nasal cytology score 3 and $10{\mu}g/m^3$ tannin exposure. The nasal cytology score 4 was seemed to be atypical squamous metaplasia. 4. To find out contributing factors to nasal cytology change, odds ratio that is one of fundmental biostatistics was applied. Actually the relationship between wooddust, tannin concentration and metaplasia were not meaningful, but the relationship between working experence more than 15 years and metaplasia was calculated as 1.83. This reveals that significant clinical abnormalities could be influenced from the years of woodworking experiences. However further research is required to evaluate the significance of the data, for the purposes of sino-nasal risk assessment, standard setting to prevent nasal cancer occurrences and possibility of changing workplace.