• Environmental Analysis Health and Toxicology
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• 제21권1호
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• pp.57-69
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• 2006

Lately human exposure to fine particles smaller than $2.5{\mu}m$ in aerodynamic diameter ($PM_{2.5}$) has become a great concern in Korea due to their possible cause of elevated mortality, lung function decrements, and more frequent hospital admissions for asthma. This study was conducted to investigate seasonal variations of human exposure to residential $PM_{2.5}$ and particle-associated polycyclic aromatic hydrocarbons (PAHs). Ten homes in Chuncheon, Korea were visited for continuous 72 hour sampling of $PM_{2.5}$ in the living rooms using a MiniVol Portable Sampler from December 22, 2002 to November 3, 2003. During the same period, outdoor $PM_{2.5}$ samples were collected on the top of the Natural Sciences Building of Kangwon National University which is located in the middle of the ten households. Samples were analyzed for $PM_{2.5}$ mass concentrations and six selected PAHs. In two smoking homes, the highest $PM_{2.5}$ concentrations were measured ranging from 51.1 to 69.7 {\mu}g/m^3$ on average in all seasons, indicating smoking is a very important contributor to the elevation of indoor particle concentrations. Seasonal comparison showed that indoor particle concentrations were higher than outdoor ones except winter. Total PAH concentrations in smoking homes were highest in winter among the seasons primarily due to low ventilation rate, followed by the outdoor site and nonsmoking homes. BaP toxic equivalents (TEQs) were calculated for five PAHs. The TEQ for smoking homes in winter was highest followed by the outdoor site in winter. It is concluded that smoking and ventilation rate are two important contributors to the elevation of indoor $PM_{2.5}$ and PAH concentrations.

• 한국환경과학회지
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• 제16권10호
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• pp.1157-1167
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• 2007

In an effort to interpret the characteristics of fine particle concentrations in Busan, time variations of hourly monitored concentrations $PM_{10}$ (Particulate Matter with aerodynamic Diameter ${\le}10\;{\mu}m$) in Busan are analyzed for the period from 2000 to 2005. The characteristics of aerosol second generation formation process is also interpreted qualitatively, by using the statistical analysis of the meteorological variables including temperature, wind speed, and relative humidity. The result shows some significant annual, seasonal, weekly and diurnal variations of $PM_{10}$ concentrations. In particular, seasonal(i.e., spring) variations are governed by frequency of yellow sand events even for the non-yellow sand cases where yellow-sand days are eliminated in our analysis. However, in seasonal variation, summer season predominate lower $PM_{10}$ concentrations due to the frequent precipitation, and weekly and diurnal variations are both found to be reflecting the emission rate from traffic amount. Correlation coefficients between $PM_{10}$ concentration and meterological variables for non-yellow sand days show overall negative correlation with visibility, wind speed, cloud amounts, and relative humidity. However for non-precipitation days, during non-yellow sand period positive correlation are found clearly with relative humidity, suggesting the importance of secondary aerosol formation in Busan that can be achieved by both homogeneous aerosol formation and heterogeneous transformations resulting from hygroscopic aerosol characteristics.

• 한국환경보건학회지
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• 제36권3호
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• pp.182-190
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• 2010

We examined the association of particulate matter with an aerodynamic diameter < $10\;{\mu}m$ ($PM_{10}$) with asthma-related hospitalization, stratified by socioeconomic status (SES), among children less than 15 years of age in Seoul, Korea, between 2003 and 2005. In addition, we estimated the reduction in the number of asthma-related hospitalizations that would result from implementing the World Health Organization (WHO) guideline. SES was defined based on data concerning health insurance premium grades, and grouped into two levels: lower-income group and control group. The lower-income group was classified as having an accumulated income which did not exceed the 50th percentile of the median income. Time-series analysis was performed to evaluate the association between $PM_{10}$ and asthma-related hospitalization. The Environmental Benefits Mapping and Analysis Program was used to analyze the impact on children's health. Based upon an increase of $10\;{\mu}g/m^3$ of $PM_{10}$, the asthma-related hospitalization risk for the lower-income group was increased by 1.78% (95% confidence intervals (CI) = 0.79-2.78%), while the risk for the control group was increased by 0.83% (95% CI = 0.34-1.32%). Attaining the WHO guideline, relative to the concentration in 2007, would result in a reduction in asthma-related hospitalizations of 18 cases per 100,000 of the children population in the lower-income group, and 7 cases in the control group. The health benefits of improved air quality for children in the lower-income group were thus 2.5 times greater than for children in the control group. Our results show that the lower-income group is disproportionately burdened with asthma-related hospitalization arising from air pollution. Therefore, biologically- and socioeconomically-disadvantaged populations should be considered in public health interventions in order to protect the children's health.

• 한국대기환경학회지
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• 제32권2호
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• pp.208-215
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• 2016

Pinic acid (PA) and cis-pinonic acid (CPA) in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal $10{\mu}m$ ($PM_{10}$) were analyzed for the samples collected during the period of April 2010 to April 2011 at Jongro in Seoul. Both pinic acid and cis-pinonic acid showed higher seasonal average concentrations in summer (PA; $18.9ng/m^3$, CPA; $16.0ng/m^3$) than winter (PA; $5.3ng/m^3$, CPA; $5.9ng/m^3$). They displayed a seasonal pattern associated with temperature reflecting the influence on emissions of ${\alpha}-pinene$ and ${\beta}-pinene$ from conifers and their photochemical reaction. These results were confirmed through Pearson correlation coefficient between CPA, PA and $O_3+NO_2$, temperature. CPA was only correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$) from biogenic source. PA was correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$), n-alkanoic acid ($C_{20}$, $C_{22}$, $C_{24}$) from biogenic source and n-alkanes ($C_{28}$, $C_{30}$, $C_{32}$), and n-alkanoic acid ($C_{16}$, $C_{18}$) from anthropogenic source. These results showed that the formation of PA and CPA from ${\alpha}-pinene$ and ${\beta}-pinene$ is related to organic compounds from biogenic source. And it is possible for PA to be effected by organic compounds from anthropogenic source.

• Toxicological Research
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• 제30권3호
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• pp.205-210
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• 2014

Didecyldimethylammonium chloride (DDAC) is used for various purposes, such as a fungicide for coolants, an antiseptic for wood, and disinfectant for cleaning. Despite the increasing likelihood of DDAC inhalation, available data on its toxicity from inhalation are scarce. Therefore, this study was aimed at confirming the toxicity of DDAC after inhalation exposure for 2 wk. Male Sprague-Dawley rats were exposed to approximately $0.15mg/m^3$, $0.6mg/m^3$, and $3.6mg/m^3$ DDAC aerosols in whole-body exposure chambers. After DDAC exposure for 2 wk, effects of DDAC on body weight, blood, bronchoalveolar lavage (BAL), and the lungs were verified. The mass median aerodynamic diameter of DDAC aerosols was $1.86{\mu}m$ and the geometric standard deviation was 2.75. The concentrations of DDAC aerosols for the low, medium, and high groups were $0.15{\pm}0.15mg/m^3$, $0.58{\pm}0.40mg/m^3$, and $3.63{\pm}1.56mg/m^3$, respectively. Body weight gain was significantly influenced by DDAC exposure. In the high group, a body weight decrease of 2.6 g was observed, whereas a 25.8 g increase was observed in the normal control group after the first 3 days. The low and medium groups showed 23.3 g and 20.4 g increases, respectively, after the first 3 days. Decreases in body weight were recovered during the next 4 days. In contrast, no changes were noted in hematological and blood biochemistry parameters after DDAC exposure. Furthermore, only mild effects were observed on bronchoalveolar cell differentiation counts and cell damage parameters in the BAL fluids of the medium and high groups. Although inflammatory cell infiltration and interstitial pneumonia were partially observed, fibrosis was not found in the lungs of the medium and high groups. In conclusion, body weight gain and the lungs were mainly affected by DDAC exposure. The no-observed-adverse-effect level (NOAEL) for DDAC was determined as $0.15mg/m^3$.

• Advances in aircraft and spacecraft science
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• 제3권3호
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• pp.243-257
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• 2016

The increase of air traffic volume has brought an increasing amount of issues related to carbon and NOx emissions and noise pollution. Aircraft manufacturers are concentrating their efforts to develop technologies to increase aircraft efficiency and consequently to reduce pollutant discharge and noise emission. Ultra High By-Pass Ratio engine concepts provide reduction of fuel consumption and noise emission thanks to a decrease of the jet velocity exhausting from the engine nozzles. In order to keep same thrust, mass flow and therefore section of fan/nacelle diameter should be increased to compensate velocity reduction. Such feature will lead to close-coupled architectures for engine installation under the wing. A strong jet-wing interaction resulting in a change of turbulent mixing in the aeroacoustic field as well as noise enhancement due to reflection phenomena are therefore expected. On the other hand, pressure fluctuations on the wing as well as on the fuselage represent the forcing loads, which stress panels causing vibrations. Some of these vibrations are re-emitted in the aeroacoustic field as vibration noise, some of them are transmitted in the cockpit as interior noise. In the present work, the interaction between a jet and wing or fuselage is reproduced by a flat surface tangential to an incompressible jet at different radial distances from the nozzle axis. The change in the aerodynamic field due to the presence of the rigid plate was studied by hot wire anemometric measurements, which provided a characterization of mean and fluctuating velocity fields in the jet plume. Pressure fluctuations acting on the flat plate were studied by cavity-mounted microphones which provided point-wise measurements in stream-wise and spanwise directions. Statistical description of velocity and wall pressure fields are determined in terms of Fourier-domain quantities. Scaling laws for pressure auto-spectra and coherence functions are also presented.

• Journal of Preventive Medicine and Public Health
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• 제51권6호
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• pp.265-274
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• 2018

Objectives: A positive association between air pollution and both the incidence and prevalence of diabetes mellitus (DM) has been reported in some epidemiologic and animal studies, but little research has evaluated the relationship between air pollution and diabetic coma. Diabetic coma is an acute complication of DM caused by diabetic ketoacidosis or hyperosmolar hyperglycemic state, which is characterized by extreme hyperglycemia accompanied by coma. We conducted a time-series study with a generalized additive model using a distributed-lag non-linear model to assess the association between ambient air pollution (particulate matter less than $10{\mu}m$ in aerodynamic diameter, nitrogen dioxide [$NO_2$], sulfur dioxide, carbon monoxide, and ozone) and emergency department (ED) visits for DM with coma in Seoul, Korea from 2005 to 2009. Methods: The ED data and medical records from the 3 years previous to each diabetic coma event were obtained from the Health Insurance Review and Assessment Service to examine the relationship with air pollutants. Results: Overall, the adjusted relative risks (RRs) for an interquartile range (IQR) increment of $NO_2$ was statistically significant at lag 1 (RR, 1.125; 95% confidence interval [CI], 1.039 to 1.219) in a single-lag model and both lag 0-1 (RR, 1.120; 95% CI, 1.028 to 1.219) and lag 0-3 (RR, 1.092; 95% CI, 1.005 to 1.186) in a cumulative-lag model. In a subgroup analysis, significant positive RRs were found for females for per-IQR increments of $NO_2$ at cumulative lag 0-3 (RR, 1.149; 95% CI, 1.022 to 1.291). Conclusions: The results of our study suggest that ambient air pollution, specifically $NO_2$, is associated with ED visits for diabetic coma.

• 한국환경보건학회지
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• 제49권1호
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• pp.30-36
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• 2023

Background: Among various pollutants, fine particle (PM_2.5, defined as particle less than 2.5 nm in aerodynamic diameter) shows the most consistent association with adverse health effects. There is scientific evidence documenting a variety of adverse health outcomes due to exposure to PM_2.5. Objectives: This study aims to assess the health benefits of that would be achieved by meeting the World Health Organization's air quality guidelines for PM_2.5 using AirQ+ and BenMAP. Methods: We estimated PM_2.5 related health benefits in Korea from implementing the World Health Organization's air quality guidelines (annual average 5 ㎍/m³ and 10 ㎍/m³) and Korea's National Ambient Air Quality Standard (annual average 15 ㎍/m³). We used World Health Organization's AirQ+ and U.S. Environmental Protection Agency's Environmental Benefits Mapping and Analysis Program. Results: The annual number of avoided PM_2.5 related premature deaths exceeding WHO guideline levels was assessed using both AirQ+ and BenMAP. We estimated that the health benefits of attaining the World Health Organization's air quality guidelines for PM_2.5 (annual average 5 ㎍/m³) would suggest an annual reduction of 26,128 (95% confidence interval [CI]: 17,363~34,024) and 26,853 (95% CI: 18,527~34,944) premature deaths. Conclusions: Our study provided useful information to policy makers and confirms that the reduction of PM_2.5 concentration would result in significant health benefits in Korea.

• Journal of Preventive Medicine and Public Health
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• 제57권2호
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• pp.108-119
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• 2024

Objectives: Abrupt changes in air pollution levels associated with the coronavirus disease 2019 (COVID-19) outbreak present a unique opportunity to evaluate the effects of air pollution on influenza risk, at a time when emission sources were less active and personal hygiene practices were more rigorous. Methods: This time-series study examined the relationship between influenza cases (n=22 874) and air pollutant concentrations from 2018 to 2021, comparing the timeframes before and during the COVID-19 pandemic in and around Thailand's Khon Kaen province. Poisson generalized additive modeling was employed to estimate the relative risk of hospitalization for influenza associated with air pollutant levels. Results: Before the COVID-19 outbreak, both the average daily number of influenza hospitalizations and particulate matter with an aerodynamic diameter of 2.5 ㎛ or less (PM_2.5) concentration exceeded those later observed during the pandemic (p<0.001). In single-pollutant models, a 10 ㎍/m³ increase in PM_2.5 before COVID-19 was significantly associated with increased influenza risk upon exposure to cumulative-day lags, specifically lags 0-5 and 0-6 (p<0.01). After adjustment for co-pollutants, PM_2.5 demonstrated the strongest effects at lags 0 and 4, with elevated risk found across all cumulative-day lags (0-1, 0-2, 0-3, 0-4, 0-5, and 0-6) and significantly greater risk in the winter and summer at lag 0-5 (p<0.01). However, the PM_2.5 level was not significantly associated with influenza risk during the COVID-19 outbreak. Conclusions: Lockdown measures implemented during the COVID-19 pandemic could mitigate the risk of PM_2.5-induced influenza. Effective regulatory actions in the context of COVID-19 may decrease PM_2.5 emissions and improve hygiene practices, thereby reducing influenza hospitalizations.

• 한국산업보건학회지
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• 제24권4호
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• pp.453-461
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• 2014

Objective: Based on the fact that fine particles are more likely to produce negative influences on the health of occupants as well as the quality of indoor air compared to coarse particles, it is critical to determine concentrations of aerosol particles with different sizes. Thus, this study focused on the size distribution and concentrations of aerosol particles in university buildings. Method: Aerosol particles in indoor air were collected from four areas: corridors in buildings(In-CO), lecture rooms(In-RO), laboratories(In-LR), and a cafeteria(In-RE). Samples were also collected from outside for comparison between the concentrations of indoor and outdoor particles. For the collection of the samples, an eight stage non-viable cascade impactor was used. Result: The average concentration of $PM_{10}$ in the samples collected from indoor areas was $34.65-91.08{\mu}g/m^3$,and the average for $PM_{2.5}$ was $22.65-60.40{\mu}g/m^3$. The concentrations of the aerosol particles in the corridors, lecture rooms, and laboratories were relatively higher than the concentrations collected from other areas. Furthermore, in terms of mass median aerodynamic diameter(MMAD), the corridors and lecture rooms had higher numbers due to their characteristics, showing $2.36{\mu}m$ and $2.11{\mu}m$, respectively. Laboratories running an electrolysis experiment showed $1.58{\mu}m$, and the cafeteria with regular maintenance and ventilation had $1.96{\mu}m$. Conclusion: The results showed that the $PM_{10}$ concentrations of all samples did not exceed indoor air quality standards. However, the $PM_{2.5}$ concentration was over the standard and, in particular, the concentration of fine particles collected from the laboratories was relatively higher, which could be an issue for the occupants. Therefore, it is important to improve the quality of the indoor air in university buildings.