• 폴리머
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• 제34권6호
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• pp.527-533
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• 2010

Pioglitazone을 봉입한 poly(lactide-co-glycolide)(PLGA) 나노입자를 emulsion-evaporation 방법을 이용하여 제조하여 최적의 나노입자와 봉입률을 조절하였다. 제조된 나노입자의 크기는 125~170 nm이었으며 30% pioglitazone이 봉입된 나노입자(3% PVA)의 봉입률은 85% 이상이었다. 이러한 나노입자들은 40일 동안 일정하게 용출이 되었다. 당뇨병 모델을 이용한 동물실험에서 글루코오스 농도를 저하시켰을 뿐만 아니라, 조직검사에서는 낮은 독성을 가지고 있는 것을 확인하였다. 이러한 결과는 pioglitazone 경구투여를 위한 약물전달을 위한 운반체로 사용될 수 있음을 확인하였다.

• 한국대기환경학회지
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• 제2권1호
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• pp.73-79
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• 1986

This study is carried out to determine the concentration of the ozone and the factors affecting the variation of ozone concentration in the ambient air in Seoul. The one-hour average concentration of ozone $(O_3)$, sulfur dioxide $(SO_2)$, nitrogen oxides (NO and $NO_2$), suspended particulate (TSP), carbon monoxide (CO) and non-methane hydrocarbon (NMHC) at 5 sites in Seoul measured from September to October in 1983 and 1984 were analysed statistically along with meteorological data for the same period. The results were as follows; 1. The average concentrations of ozone at 5 sites during the period ranged from 3.3 to 9.1 ppb, they were below 20 ppb of the ambient air quality standard of Korea. 2. The maximum hourly concentration of ozone occurred between 2 and 3 p.m. in a day and concentration at night were very low but higher concentrations were observed at around 4 a.m. 3. The concentration ratio between NO and $NO_2$ in Seoul was relatively lower than that for the cities of foreign countries reported so far. 4. The ozone concentration has negative correlationships with the concentration of other primary pollutants$(SO_2, NO, NO_2, CO and NMHC)$ in simple regression analyses. 5. The ozone concentration was positively correlated to wind speed, temperature and insolation intensity but negatively correlated to relative humidity. 6. Stepwise multiple regression analysis of the ozone concentration to the pollutants and meteorological factors indicate that insolation intensity and $[NO_2]/[NO]$ were the primary influencing factors. 7. The three factors of insolation intensity, $[NO_2]/[NO] and NO_2$ concentration had a significant combined effect on the ozone concentration $(r^2 = 0.47-0.57)$.

• 한국대기환경학회지
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• 제19권1호
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• pp.33-44
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• 2003

The atmospheric concentrations of particulate polycyclic aromatic hydrocarbons (PAHs) associated with PM$_{10}$ were determined in Taegu metropolitan area. Sampling was undertaken every five days throughout one year period from 1993 to 1994 at four sites, representing a residential, a commercial, an industrial, and a sub-urban area, respectively. Benzo (e) pyrene, benzo (k) fluoranthene, and chrysene were found to be the most abundant com-pounds during the study period. The concentrations of benzo (a) pyrene, one of carcinogenic PAHs, ranged 2.0~4.8 ng/㎥ in winter and 0.5~1.5 ng/㎥ in summer season, indicating a marked seasonal variation. It was found that there were very similar patterns in the relative profiles of PM$_{10}$-bound PAH concentrations among the four sampling sites, while the absolute levels of each PAH were significantly different from each site. In addition, the patterns of summer to winter concentration ratios for each PAH were almost identical between the different sites. Despite difficulties due to the lack of good markers for specific sources in the target compounds, we were able to evaluate and describe the effects of vehicle emissions and space heatings, using relative profiles of PAHs, winter to summer (W/S) ratios, PAH-to-PAH ratios, and the result of principal component analysis. As a con-sequence, it was concluded that the vehicle emissions in urban and sub -urban areas are likely to be a major contributor for PAH loadings in the ambient atmosphere during the non-heating season, while the contributions of residential heating and local industrial oil burning emissions were highly significant in heating season.son.

• 한국대기환경학회지
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• 제12권5호
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• pp.555-566
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• 1996

In order to assess the long-term airborne concentrations of 6 metals such as Cr, Cd, Pb, Zn, K, and Na and the associated health resk, a great number of PM-10 samples were collected and analyzed in Kyung Hee University-Suwon Campus for three years from 1991 to 1993. The 3-year average concentration of Pb in respirable particulate matters was 142.6 ng/m$^{3}$ while that of Zn was 1,210.5ng/m$^{3}$. The corresponding hazard index from Pb Zn for the ingalation route was estimated to be 9.5.times.10$^{-2}$ and 3.5.times.10$^{-2}$ , respectively. Therefore, it can be said that there was no adverse chronic health effects by airborne Pb and Zn. However, the 2-year average concentration of Cr(6) was estimated to be 1.3ng/m$^{3}$ shile the 3-year average concentration of Cd was 3.1ng/m$^{3}$. The total cancer risk by these two metals for the inhalation route was estimated to be about 7.2.times.10$^{-6}$ . This order-of-magnitude risk estimate suggests that the ingalation risk in the study area from all carcinogenic metals including As and Ni (subsulfide) might exceed the acceptable risk criteria of 10$^{-5}$ -10$^{-6}$ by U.S.EPA.For a better risk assessment in the future, alveolar deposition of PM-10 in the study area were also discussed and an assessment was done.

• 한국대기환경학회지
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• 제18권5호
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• pp.419-426
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• 2002

The concentrations of three different fractions of particulate matters including PM2.5, PM10, and TSP were compared between the Asian Dust (AD) and non-AD (NAD) periods during the spring season of 2001. For the purpose of this comparative analysis, the data sets were obtained from four different observatory sites located within the city boundary of Seoul that concurrently measure those three fractions of PM at hourly intervals. According to our study, several conclusions can be drawn to describe relationships between the AD event and PM distribution characteristics. First of all, it is apparent that the concentrations of PM are distinctively distinguished between AD and NAD. If the extent of contribution to the AD events are assessed on the quantitative basis, it appears that their magnitude increases on the order of PM2.5, PM10, and TSP. As a result, the increase of PM observed during AD event is dominated by the coarse rather than fine fraction of PM. Moreover, when their relationships were assessed in terms of fractional ratios, it was found that TSP/PM10 ratios were almost constant, regardless of the occurrences of AD. On the other hand, the coarse/fine or TSP/PM2.5 ratios changed dramatically between AD and NAD periods. The results of our analysis cleary distinguishes quantitative role of each PM fraction between AD and NAD period, while suggesting indirectly the possible control of source processes on such relationships.

• 한국대기환경학회지
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• 제34권2호
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• pp.259-268
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• 2018

The $PM_{2.5}$ samples were collected for every 6th day during one year at a suburban site in the Namwonsi, Jeollanamdo, Republic of Korea. Samples were analyzed for elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC), and levoglucosan. Although the water-soluble fraction of fine particulate OC consistently showed over a year, levoglucosan fraction of WSOC varied considerably from month to month. In this study, non-biomass-burning WSOC ($WSOC_{NBB}$) and biomass-burning $WSOC_{BB}$ were calculated with measurements of organic source tracer, levoglucosan, to better understand the temporal distribution and sources of WSOC. Two methods of predicting the secondary organic carbon from the biomass-burning $WSOC_{BB}$ Method and the EC-tracer Method were compared. Poor correlations between SOC estimated between two methods suggested that the use of the EC tracer method to estimate SOC may be significantly flawed. Direct measurements of levoglucosan and WSOC can provide a reasonable estimate of secondary organic carbon concentrations.

• 한국산업보건학회지
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• 제23권4호
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• pp.356-366
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• 2013

Objectives: This study was conducted in order to evaluate $PM_{2.5}$ concentrations at 20 offices connected to the manufacturing industry from the beginning of September to the end of November 2012. Methods: A total of 20 samples were collected from 20 office buildings. Each $PM_{2.5}$ sample was collected by a 37 mm PTFE filter attached to a Personal Environment Monitor. Results: The geometric mean concentrations of $PM_{2.5}$ in the offices was $23.47{\mu}g/m^3$, and the mean $PM_{2.5}$ concentrations measured in smoking offices were much higher than those of measured in non-smoking offices($24.83{\mu}g/m^3$ and $21.55{\mu}g/m^3$, respectively). $PM_{2.5}$ was revealed to be higher in small offices($39.52{\mu}g/m^3$) than in medium or large offices($22.69{\mu}g/m^3$ and $11.04{\mu}g/m^3$, respectively). The mean $PM_{2.5}$ concentration of offices located on the 1st floor was higher than that of those on the 2nd floor, and those of offices located in the workplace were higher than those out of the workplace. The multiple regression model showed that concentration of $PM_{2.5}$ was positively associated with the method of ventilation. Conclusions: Smoking, ventilation method, location, and inflow of outdoor particulate matter are the most important factors for office $PM_{2.5}$ concentrations.

• 한국환경보건학회지
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• 제36권4호
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• pp.294-305
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• 2010

This study estimated the health risk of heavy metals in particulate matter $(PM)_{2.5}$ in a Gwangyang industrial complex. The $PM_{2.5}$ containing heavy metal was collected from January to November, 2008 using a denuder air sampler and by IC (Ion Chromatograph). The risk assessment was performed in a four-step process; hazard identification, exposure assessment, dose-response assessment and risk characterization. In the hazard identification process, $Cr^{6+}$, Ni, As, and Pb were categorized as human carcinogens and probable human carcinogens, while Ti, Mn, Se, P, $Cr^{3+}$, Cu, and Zn were not classified as human carcinogens. It was found that the excess cancer risk by Central Tendency Exposure (CTE) of $Cr^{6+}$ and As in $PM_{2.5}$ was > $10^{-6}$, and the total excess cancer risk posed by carcinogen heavy metals in $PM_{2.5}$ was > $10^{-6}$. It was also determined that the total hazard index by CTE of non-carcinogen heavy metals in $PM_{2.5}$ was <1. Taken together, these results indicate a high cancer risk associated whit inhalation of heavy metal-containing$PM_{2.5}$ in industrial areas.

• 한국대기환경학회지
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• 제33권2호
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• pp.77-86
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• 2017

Globally, use of affordable fuels such as briquettes, woods and wood pellets has increased. Organic pollutants emitted from non-point sources using solid fuels may have contributed to air pollution in urban environment. In this study, we utilized simulated incinerator proposed by U.S. EPA and investigated concentrations of PM, $PM_{10}$, $PM_{2.5}$, OC/EC, CO, $SO_x$, $NO_x$, VOCs and PAHs emitted while cooking meat and fish using briquettes, woods and wood pellets, and developed emission factors. As a result, wood combustion produced more air pollutants than the others. Particulate matter emission factors for woods and wood pellets were 13.54 g/kg and 9.15 g/kg, respectively. Total VOCs emission factors for briquettes, woods and wood pellets were 36.12mg/kg, 46.13mg/kg and 18.26mg/kg, respectively. Additionally, total PAHs emission factors for briquette, woods and wood pellets were 0.44 mg/kg, 18.84mg/kg and 101.62mg/kg, respectively.

• 분석과학
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• 제13권2호
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• pp.179-188
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• 2000

대기환경시료인 도시분진시료와 인공적으로 준비한 휠터상 도시분진시료중의 미량원소를 중성자방사화분석법을 사용하여 비파괴 분석하였다. 분석정도관리를 위하여 미국 표준기술원의 인증표준시료 (Urban Dust, NIST SRM 1648)를 이용하였다. 37종의 검출된 원소의 상대오차와 상대 표준편차를 계산하였으며 각각 10%와 15%이내이었다. 도시분진시료로부터 29종의 원소, 휠터상 도시분진시료로부터 21종의 원소를 정량하였다. 측정결과의 신뢰도 및 숙련도 평가를 위하여, 중성자방사화분석법, 하전입자유도 X-선방출분광법, X-선 형광분석법과 원자흡수분광법을 이용한 세계 39개 실험실이 참여한 실험실간 비교시험에 참여하였으며 수집된 결과를 통계처리하였다. 평균값과 표준편차로 계산한 z-score는 몇개의 원소를 제외하고 모두 -1