• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.277-288
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• 2017

Previous studies of health effects of $PM_{2.5}$ performed spatial monitoring campaigns to assess spatial variability of $PM_{2.5}$ across people's residences. Highly reliable portable and cost-effective samplers will be useful for such campaigns. This study aimed to investigate applicability of the Deployable Particulate Impact Sampler(DPIS), one of the compact impact samplers, to spatial monitoring campaigns of $PM_{2.5}$ in Seoul, Korea. The investigation focused on the consistency of $PM_{2.5}$ concentrations measured by DPISs compared to those by the Low-volume Cyclone sampler (LCS). LCS has operated at a fixed site in the Seoul National University Yeongeon campus, Seoul, Korea since 2003 and provided qualified $PM_{2.5}$ data. $PM_{2.5}$ sampling of DPISs was carried out at the same site from November 17, 2015 through February 3, 2016. $PM_{2.5}$ concentrations were quantified by the gravimetric method. Using a duplicated DPIS, we confirmed the reliability of DPIS by computing relative precision and mean square error-based R squared value ($R^2$). Relative precision was one minus the difference of measurements between two samplers relative to the sum. For accuracy, we compared $PM_{2.5}$ concentrations from four DPISs (DPIS_Tg, DPIS_To, DPIS_Qg, and DPIS_Qo) to those of LCS. Four samplers included two types of collection filters(Teflon, T; quartz, Q) and impaction discs(glass fiber filter, g; pre-oiled porous plastic disc, o). We assessed accuracy using accuracy value which is one minus the difference between DPIS and LCS $PM_{2.5}$ relative to LCS $PM_{2.5}$ in addition to $R^2$. DPIS showed high reliability (average precision=97.28%, $R^2=0.98$). Accuracy was generally high for all DPISs (average accuracy=83.78~88.88%, $R^2=0.89{\sim}0.93$) except for DPIS_Qg (77.35~78.35%, 0.82~0.84). Our results of high accuracy of DPIS compared to LCS suggested that DPIS will help the assessment of people's individual exposure to $PM_{2.5}$ in extensive spatial monitoring campaigns.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.275-276
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• 2003

산업의 발달에 따른 환경 오염물질의 증가와 오염물질의 종류가 다양화됨에 따라 대기 중의 유해원소 및 미량원소에 의한 환경오염과 그로 인한 인체건강에 대한 영향은 인간생활에 심각한 문제가 되므로 대기 중의 농도를 정확히 측정하는 것은 매우 중요한 일이다. 특히 미세 입자는 오염된 도심지역 분진수의 90∼99%에 이르는 높은 비율을 보이고 있고, 폐 깊숙이 침투하여 폐암을 비롯한 폐질환을 일으킬 수 있다. (중략)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.324-333
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• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.1-8
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• 2016

In this study, we investigated the applicability of a short-term carbon dioxide ($CO_2$) passive sampler using turbidity change in a solution containing barium hydroxide ($Ba(OH)_2$). The mass of $CO_2$ introduced into the $Ba(OH)_2$ aqueous solution was strongly correlated ($r^2=0.9565$) to the change in turbidity caused by its reaction with the solution. The sampling rates calculated for 1 h and 24 h were $42.4{\pm}5.4mL\;min^{-1}$ and $2.3{\pm}0.3mL\;min^{-1}$, respectively. Both unexposed (blank) and exposed samplers remained stable during the storage period of at least two weeks. The detection limits of the passive sampler for $CO_2$ were 81.5 ppm for 1 h and 61.5 ppm for 24 h. Based on the results, the passive sampler using the change of turbidity in the $Ba(OH)_2$ aqueous solution appears to be a suitable tool for measuring short-term atmospheric concentrations of $CO_2$.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.E1
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• pp.1-8
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• 2006

The purpose of this study was to evaluate the efficiency of a passive sampler in measuring atmospheric ammonia concentrations using chamber system. The ability of the passive sampler to quantitatively determine atmospheric ammonia gas was almost identical to that of the reference method (indophenol method). There was no significant difference between concentrations measured by the two methods. The detection and quantification limits of the ammonia passive sampler were 16.9 ppb and 25.3 ppb, respectively, for a 24-h sampling period. The average coefficient of variation between replicated samplers was $6.7{\pm}4.2%$. The concentrations measured by the two methods (passive sampler and indophenol method) were no significant difference with good a correlation (correlation coefficient=0.964).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.330-332
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• 2000

삶의 질 향상을 위한 쾌적한 대기환경의 관리 유지는 우리 모두의 관심사중의 하나이다. 호흡기관을 통해 인체내로 흡입되는 $PM_{10}$ 대기분진은 자연적이고 인위적인 발생원에 의해 다양한 미량원소들을 함유하고 있기 때문에 흔히 환경영향 평가를 위한 대기관측시료로 이용되고 있으며, 특히 $PM_{2.5}$ 분진의 질량농도(TSPM)나 원소의 농도가 높을 때 장.단기적으로 인체 보건에 큰 영향을 미치는 것으로 알려져 있다. (중략)

• Journal of Environmental Science International
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• v.13 no.3
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• pp.215-222
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• 2004

This study was conducted to evaluate the characterization of airborne bioaerosol in public facilities in Seoul. A total of 17 public facilities were investigated from December, 2002 to February, 2003. As results of the survey, the mean concentrations of bacteria and fungi in indoor air of public facilities were $378.08\pm296.33$ CFU/㎥ by RCS and $106.38\pm171.63$ CFU/㎥ and $347.46\pm335.32$ CFU/㎥ and $95.23\pm62.61$ CFU/㎥, by Six-stage cascade air sampler respectively. The mean concentrations of bacteria in indoor air (by ventilation method) were $517.14\pm343.93$ CFU/㎥ of natural ventilation and $215,83\pm100.71$ CFU/㎥ of mechanical ventilation. The mean concentrations of fungi in indoor air (by ventilation method) were $83.14\pm79.16$ CFU/㎥ of natural ventilation and $133.50\pm248.07$ CFU/㎥ of mechanical ventilation. The mean concentrations of bacteria in indoor air were 449.44 CFU/㎥ for the ground and $217.50\pm103.68$ CFU/㎥ for the underground. The mean concentrations of fungi in indoor air were $63.89\pm77.66$ CFU/㎥ for the ground and $202.00\pm290.08$ CFU/㎥ for the underground.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.1
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• pp.117-126
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• 2006

The purpose of this study is to develop a badge-type passive sampler for the measurement of short-term nitrogen dioxide and to evaluate its performance. The principle of the method is a colorimetric reaction of nitrogen dioxide with sulfanilic acid, N-1-naphthylethylendiamine, and phosphoric acid. First, it has been shown that the filter paper should be rinsed with ultrapure water and ultrasound, and then dried in a vacuumed desiccator. The concentration and volume of absorption reagent (triethanolamine) were $20\%$ and 100 ${\mu}L$, respectively. The extraction time was determined as 60 min. Second, duplicate measurements (n= 116) were carried out for evaluating the precision of the passive sampler. The relative error and the correlation coefficient between duplicates are $3.4\pm 3.0\%$ and 0.994, respectively. In addition, the $95\%$ confidence interval of intraclass correlation coefficient and the estimated value are 0.992$\sim$0.996 and 0.994, respectively. Third, a paired t-test was carried out for evaluating the accuracy of the passive sampler (n=40). In the result of the test, the $95\%$ confidence interval of the difference was -1.710 ppb <$\gamma$< 0.788 ppb. Finally, the average concentration of blanks, measurement detection limit, limit of detection, and limit of quantification are $2.4\pm 0.4$ ppb, 104 ppb, 3.8 ppb, and 7.0 ppb, respectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.21-31
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• 1997

Toluene, n-hexane, and methyl ethyl ketone(MEK) were exposed to the activated carbon fiber(ACF) and 3M(Model 3500) diffusive samplers under low and high humidity levels. In order to evaluate these two samplers, the sampling capacity, sampling rate, reverse diffusion, and storage stability were obtained. At low humidity level($8{\pm}3%RH$), the adsorption amount of all three organic vapors to the ACF diffusive sampler showed a positive linear relationship up to 8 hours. However, at high humidity level($90{\pm}5%RH$), n-hexane and MEK maintained a positive linear relationship up to 1.5 hrs, but decreased in their adsorption amounts afterwards. On the other hand, the adsorption amount of n-hexane, MEK, and toluene to 3M diffusive sampler showed almost a positive linear relationship up to 8 hours at both humidity levels. At low humidity level, there was almost no reverse diffusion for both 3M and ACF diffusive samplers. However, when the ACF diffusive sampler was used at high humidity level, there was about 52.63% of MEK sample loss and about 92.59% of n-hexane sample loss. The storage stabilities of the ACF and 3M diffusive samplers were both relative stable except for MEK. In the case of MEK, the difference between the analysis of the organic vapor right after the sampling and that of 3 weeks later at room temperature was 45% for the ACF diffusive sampler and 18% for the 3M diffusive sampler. Since the storage stability of the samples stored in a refrigerator was relatively stable, they need to be refrigerated until the analysis is done.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.111-117
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• 1997

Recently, the conclusion of Comprehensive Test Ban Treaty(CTBT) is globally constructing a network system for nuclear test monitoring. The radionuclide experts of the Conference on Disarmament recommended that the detection of nuclear debris in the atmosphere was an essential factor of nuclear test monitoring and proposed the technical requirements. Based on those requirements, atmospheric radionuclide monitoring system to detect nuclear debris generated from the nuclear explosion test was composed. The system is comprised of high volume air sampler(HVAS), filter paper presser and high purity germanium detector(HPGe). Minimum detectable concentrations(MDCs) of the key nuclides requiring in CTBT monitoring strategies are determined by considering of decay time, counting time and flow rate of the high volume air sampler for the rapid explosion and the optimum measurement condition. The results were selected $10{\pm}$2h, $20{\pm}$2h and $850{\pm}50m^3$/h as parameters, respectively. The relation between the natural air-borne radionuclide concentration of $^{212}Pb$ and MDC were calculated which gave effect in the Compton continuum baseline due to those nuclides in the gamma-ray spectroscopy. These results can be used as an actually tool in the CTBT monitoring strategies.