• Environmental Analysis Health and Toxicology
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• v.26
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• pp.4.1-4.6
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• 2011

Objectives: This study was carried out to determine whether or not pine needles can be used as passive samplers of atmospheric polycyclic aromatic hydrocarbons (PAHs) using the correlation between accumulated PAH concentrations in air (Ca, ng/$m^3$) and those deposited on pine needles (Cp, ng/g dry). Methods: PAHs in ambient air was collected using low volume PUF sampler and pine needles was gathered at same place for 7 months. Results: A good correlation ($R^2$=0.8582, p<0.05) was found between Ca and Cp for PAHs with a higher gaseous state in air (AcPy, Acp, Flu, Phen, Ant, Flt, Pyr, BaA and Chry), but there was a poorer correlation ($R^2$=0.1491, p=0.5123) for the PAHs with a lower gaseous state (BbF, BkF, BaP, DahA, BghiP and Ind123). A positive correlation ($R^2$=0.8542) was revealed between the logarithm of the octanol-air partitioning coefficient ($logK_{oa}$) and Cp/Ca for the PAHs with a higher gaseous state in air, but there was a negative correlation ($R^2$=0.8131) for the PAHs with a lower gaseous state. The Ca-Cp model could not be used to estimate PAHs concentrations in air using deposited PAHs concentrations on pine needles, but the logKoa-Cp/Ca model could be used. Conclusions: It was found that pine needles can be used as passive samplers of atmospheric PAHs.

• Journal of Environmental Science International
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• v.19 no.4
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• pp.447-457
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• 2010

This study aims to monitor the variation of concentration of PCDD/DFs between the gaseous phase-particulate phases in the ambient air of urban area in Korea. This monitoring is evaluated by using the Junge-Pankow model and the Koa absorption model with the application of the Octanol-air partition coefficient. In this study, the ambient air samples were analyzed according to each congener group of the PCDD/DFs by HRGC/HRMS, which have been investigated for the past 5 years. In the results, the annual variation in the concentration level of $\Sigma$PCDD/DFs in TSP was increased from $1588\;fg/m^3$ in 1998 to $5123\;fg/m^3$ in 2002, and from 31 fg I-TEQ/$m^3$ to 94 fg I-TEQ/$m^3$ in the $\Sigma$I-TEQ. In the case of PUF of gaseous phase sample, their variation was increased from $1615\;fg/m^3$ in 1998 to $2237\;fg/m^3$ in 2002, and in the $\Sigma$I-TEQ from 12 fg I-TEQ/$m^3$ to 17 fg I-TEQ/$m^3$. The relative coefficient between the gas phase concentration of PCDD/DFs and the temperature was a value of 0.744; the contributive rate of the temperature to the gaseous phase concentration was 0.554. According to the results, the pattern of the coefficient of distribution based on log $p_L^0$ is similar to the ambient air of the urban areas.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.391-393
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.359-360
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.233-234
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.391-392
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.352-353
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• 2009

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.04a
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• pp.201-202
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• 1999

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.492-500
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• 2014

Objectives: The purpose of this study is to estimate the applicability of regional sample collection of environmental samples. The concentration of asbestos fibers were analyzed with two devices. One was an existing commercial air sampling pump that has been proved to be accurate and exact, and the other is a remodeled pump for sample collection which was made from an electric bubble generator originally designed for aquarium fish. Samples were collected with the two devices under the same environmental conditions and collection equipment. A comparative analysis of the concentration of ambient asbestos fiber was then performed. Methods: Based on previous research, six farmhouses with asbestos fiber slate roofs known to have high concentrations of asbestos fiber were selected. Using the existing commercial air sampling pump and the remodeled electric bubble generator, four to seven samples were collected each day one meter downwind from the edge of the slate roof at high volume (about 4 L/min) and low volume (about 1.4 L/min). The analyzer responsible for sample quality control of asbestos fibers counted the number of asbestos fibers with a phase microscope. Results: The rates of flow change of the existed sampler and the remodeled pump at high volume were 0.82% and 0.17%, respectively. The rates of flow change at low volume were 3.83% and 1.09%, but there was not significant difference. The rates of flow change are within the error range (${\pm}5%$) of OSHA analyzing methods. For the high volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 6.270 fibers/L and for the remodeled one 5.527 fibers/L, not a significant difference. For the low volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 7.755 fibers/L and for the remodeled one 7.706 fibers/L, not a significant difference. The total area of the slate roof of the targeted farmhouse has an effect on the concentration of asbestos fibers in the air from the existing pump and the remodeled one (p<0.01). Conclusions: The sampling function between the existing commercial pump and the remodeled one shows little difference. Therefore, the remodeled pump is considered a pump with a good availability for collecting ambient air asbestos samples.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.163-167
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• 2016

Inverter surge resistant enameled wire was prepared with an organic/inorganic hybrid nanocomposite, and the effect of ambient temperature on the insulation lifetime of the enameled wire in the form of twisted pair was studied by a withstanding voltage tester. The organic polymer was Polyesterimide-polyamideimide (EI/AI) and the inorganic material was a Nano-sized silica (average particle size : 15 nm). The enamel thickness was 50 μm and the ambient temperature was 100, 150, 200, and 250, respectively. Transmission electron microscopy (TEM) observation showed that Nano-sized Silica were evenly dispersed in EI/AI. There were many air gaps in a twisted pair, therefore, when voltage was applied to the twisted pair, enamel erosion took place in the air gap area because of partial discharge accordi, ng to Paschen’s law. As ambient temperature increased, insulation lifetime decreased according to Arrhenius relationship, which was explained by the increasing mobility of polymer chains in EI or AI. And insulation breakdown voltage value at 10 kHz was 1,864.5 sec (31.1 min), which is 1.9 times higher than at 20 kHz, 981.6 sec (16.4 min).