• Tuberculosis and Respiratory Diseases
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• 제85권3호
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• pp.237-248
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• 2022

Background: We evaluated the effect of particulate matter (PM) and cigarette smoke extract (CSE) on bronchial epithelial cell survival, as well as oxidative stress and autophagy levels. Moreover, we aimed to assess the effect of the antioxidant N-acetylcysteine (NAC) on the adverse effects of PM and CSE exposure. Methods: Normal human bronchial epithelial cells (BEAS-2B cells) were exposed to urban PM with or without CSE, after which cytotoxic effects, including oxidative stress and autophagy levels, were measured. After identifying the toxic effects of urban PM and CSE exposure, the effects of NAC treatment on cell damage were evaluated. Results: Urban PM significantly decreased cell viability in a concentration-dependent manner, which was further aggravated by simultaneous treatment with CSE. Notably, pretreatment with NAC at 10 mM for 1 hour reversed the cytotoxic effects of PM and CSE co-exposure. Treatment with 1, 5, and 10 mM NAC was shown to decrease reactive oxygen species levels induced by exposure to both PM and CSE. Additionally, the autophagy response assessed via LC3B expression was increased by PM and CSE exposure, and this also attenuated by NAC treatment. Conclusion: The toxic effects of PM and CSE co-exposure on human bronchial epithelial cells, including decreased cell viability and increased oxidative stress and autophagy levels, could be partly prevented by NAC treatment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.802-806
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• 2001

Diesel particulate trap is the most reliable system to reduce the particulate matters from diesel engine. Filter is the core component of DPF and ceramic monolith type is dominantly used, which is expensive and fragile relatively at thermal shock. Porous metal filter, which has superior thermal characteristics and low cost, was tested in order to analyze the regeneration performance by using with ferrocene additive. This filter showed the 72% filtration efficiency, additives itself diminished 48% of PM from engine out emission, and final PM reduction ratio of 89% was achieved by DPF system with D-13 test mode.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.165-172
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• 2015

Under a very tough situation that there has been increasing concern to the air quality in underground subway spaces, this study set sights on the thorough estimation of the chemical properties and source apportionment of particulate matter (PM) collected on an underground subway platform by a cooperative approach of semi-bulk and single particle analyses. The size-resolved PMs were intensively collected on the platform of Miasageori station on the Seoul Subway Line-4, and then, they were semibulkily analyzed by a PIXE and the TOR$^{(R)}$ method, and individually analyzed by a SEM-EDX. Overwhelmingly enriched iron was a notable feature of elemental concentration of $PM_{2.5}$. Source classification of iron in $PM_{10-2.5}$ and $PM_{2.5}$ performed along with their elemental concentrations, indicates that the railway originated iron accounts for 95.71% and 66.39% of total iron in $PM_{10-2.5}$ and $PM_{2.5}$, respectively. Via a stoichiometric categorization, $Fe_2O_3$, $CaAl_2Si_2O_8$, $Al_2O_3$, and $CaCO_3$ show more than 85% abundance ratio in individual coarse particles. The result of theoretical estimation of the subway derived organic carbon ($OC_{Subway}$) suggests that $OC_{Subway}$ in $PM_1$ and $PM_{2.5-1}$ account for 75.86% and 51.88% of total organic carbon, respectively.

• 한국산업보건학회지
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• 제27권1호
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• pp.46-58
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• 2017

Objectives: Particulate matter (PM) at construction sites mostly originates from either construction activities or the atmospheric environment. This study was conducted to evaluate the exposure level to PM and the contribution ratio of atmosphere sources at construction sites. Methods: We reviewed literature and governmental systems related to PM exposure in occupational settings and summarized them. In the field evaluation, five construction sites and one golf course were selected: two from Gyeonggi-do Province and four from North Gyeongsang-do Province. For each site, personal samples from outdoor construction workers and area samples from the outdoor area around the construction site office were collected according to construction work types. PM concentrations reported from nearby National Ambient Air Monitoring Stations were recorded. Respirable dust concentrations, respirable silica concentrations, and several metal concentrations including Cd, Cr, Pb, and As were monitored over four months. In the end we suggested how to manage particulate matter exposure at construction sites. Results: There was little literature reporting on exposure levels of construction workers to PM. Respirable dust concentrations measured in Gyeonggi-do Province were higher than those measured in North Gyeongsang-do Province. The geometric means of respirable dust concentrations in personal samples and area samples were $37.89{\mu}g/m^3$ and $92.86{\mu}g/m^3$, respectively. The respirable dust concentrations were higher than the PM concentrations reported from nearby National Ambient Air Monitoring Station. The geometric means of respirable silica concentrations of personal samples and area samples were $1.3{\mu}g/m^3$ and $1.1{\mu}g/m^3$, respectively. All metal concentrations were lower than 10% of individual Korean occupational exposure limits. Conclusions: Assuming that personal samples consisted of ambient PM and dust originating from work activities and area samples only collected ambient PM, we concluded that the dust exposure of outdoor construction workers originated 40.8% from the atmosphere and 59.2% from construction activities. PM exposure at construction sites should be controlled by employers, as in the case of outdoor heat stress. The Korean government needs to consider setting an occupational exposure limit for respirable dust.

• 대한화학회지
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• 제44권6호
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• pp.600-610
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• 2000

본 연구에서는 전통적인 입자모델 교수 전략의 문제점을 분석하여, 잘 변화하지 않는 학습자의 신념체계인 연속적인 물질관을 입자적인 물질관으로 변화시킬 수 있는 새로운 입자모델 교수 전략으로 반성적 사고를 촉진시키는 입자모델 교수 전략을 고안하였다. 고안된 반성적 사고를 촉진시키는 입자모델 교수 전략을 초등학교 예비교사를 대상으로 처치한 후, 반성적 사고를 촉진시키는 입자모델 교수 전략의 효과를 전통적인 입자모델 교수전략과 비교 분석하였다. 전통적인 입자모델 교수전략의 문제점으로는 1) 입자모델을 실제물과 연결시켜 생각하지 못하는 문제점, 2) 입자모델을 학습할 때 무조건 암기하는 학습전략을 사용하는 경향이 높은점, 3) 입자모델을 수없이 학습한 후에도 연속적 물질관을 입자적 물질관으로 변화시키지 못하는 학생의 비율이 매우 놓은점, 4) 물질을 학습할 때 과학적 상황으로 학습하므로 물질에 대한 사고가 과학적 상황에 제한되어 있어 일상적 상황으로 연관시키지 못하는 문제점 등이 있다. 전통적인 과학적 상황의 입자모델 교수전략과 반성적 사고를 촉진시키는 일상적 상황의 입자모델 교수전략의 효과를 비교한 결과 일상적 상황의 입자모델 교수전략이 개념이해측면, 흥미측면, 입자적 물질관 형성정도, 기억측면에서 더 효과적인 것으로 나타났다. 본 연구결과로부터 얻을 수 있는 과학교육에의 중요한 시사점은 일상적 상황의 입자모델 교수전략 방법이 과학을 과학적 상황(실험실 상황)에서만 국한되어 사고하는 것이 아니라, 학교 과학 수업시간에 학습한 과학을 일상 상황과 연관시켜 사고할 수 있도록 해 준다는 것이다.

• 대한임베디드공학회논문지
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• 제13권4호
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• pp.179-185
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• 2018

Particulate Matter (PM2.5) has various adverse effects on health. Climate and industry activity and traffic volume are the main causes, especially in urban area. In order to construct an effective forecasting system, many measurement systems are required, but it is impossible in reality. Therefore, in this study, we propose a method to infer PM2.5 condition by using rule induction technique. The experimental results showed a classification accuracy of 71%.

• 한국환경과학회지
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• 제23권12호
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• pp.2029-2034
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• 2014

To improve air quality around a broad way, Daegu Metropolitan city employed the clean-road system at a part of the broad way of Dalgubul (Daigubul-daero) in 2011. The clean-road system in general is operated two times (4 am, 2 pm) during summertime. In case of scorching alert, the system is operated 3 times a day (4 am, 2 pm and 4 pm). To evaluate the effect of air quality improvement due to the system, we analyzed the time variation of monthly mean particulate matter (PM10) concentration in recent 3 years (2011-2013). The improvement of air quality was estimated at about 5~15 % under the system.

• 대한원격탐사학회지
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• 제36권6_3호
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• pp.1721-1732
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• 2020

초등학생들은 학교에서 많은 시간을 보내고 있으며 실내 공기오염에 더 많이 노출된다. 또한 초등학생들은 신체적으로 성장기에 있으며 어른에 비해 단위체중당 호흡량이 많으므로 실내 공기오염에 대한 민감도가 큰 것으로 알려져 있다. 따라서 학교 실내공기질은 초등학생들의 건강을 위한 중요한 요소이다. 본 연구에서는 서울지역 5개 초등학교에서 측정한 실내외 미세먼지 (Particulate matter: PM) 농도를 이용하여 상관분석을 실시하였다. 이를 통해 실외 PM이 실내 PM에 미치는 영향을 평가하였다. 또한 PM ratio, I/O ratio 등과 같은 통계분석을 진행하였다. 그 결과 초등학교의 실내외 PM의 상관성은 PM10보다 PM2.5와 PM1에서 더 유의미하게 나타났다. Indoor/outdoor (I/O) ratio의 경우 PM10에서 SD를 제외한 4개 초등학교에서 모두 1보다 높게 나타났다 (BB: 2.21, NS: 1.67, IS: 1.73, SI: 1.17). 이는 실내 학생의 활동도가 PM10의 농도에 큰 영향을 미친다는 것을 의미한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2245-2250
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• 2003

Particulate matters(PM) have bad effect on the health. We carried out measurements of diesel PM under $10{\mu}m$ diameter from a HSDI diesel engine with a diesel oxidation catalyst(DOC) by using the ELPI. This paper compares the two results of the smoke level and the PM level of masses and numbers. We also investigated the effect of the DOC. Under high speed and load, HSDI diesel engine exhausts much masses of particulate matters over 100nm diameter, and a number of PM from 7 to 100nm diameters at the same condition. DOC could reduce the total mass of the PM. However, the DOC could increase the number of ultra fine PM. Before light-off of the soot, the DOC absorb the PM and the DOC oxidize the PM after light-off temperature. The fine PM could be made during the oxidation. Therefore, the advanced DOC is needed to reduce the number of the fine PM.

• 한국환경보건학회지
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• 제33권6호
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• pp.479-487
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• 2007

[ $PM_{2.5}$ ], particulate matter less than 2.5 um in a diameter, can penetrate deeply into the lungs. Exposure to $PM_{2.5}$ has been associated with increased hospital visits for respiratory aliments as well as increase mortality. $PM_{2.5}$ is a byproduct of combustion processes and as such has a complex composition including a variety of metallic elements, inorganic and organic compounds as well as biogenic materials (microorganisms, proteins, etc). In this study, the average concentrations of fine particulates $PM_{2.5}$ have been measured simultaneously in Asan and Seoul, Korea, by using particulate matter portable sampler from September 2001 to August 2002. Sample collection filters were analyzed by ICP-OES to determine the concentrations of metallic elements (As, Ni, Fe, Cr, Cd, Cu, Pb, Zn, Si). Annual mean $PM_{2.5}$ concentrations in Asan and Seoul were 37.70 and $45.83\;{\mu}g/m^3$, respectively. The highest concentrations of $PM_{2.5}$ were found in spring season in both cities and the concentrations of measured metallic elements except As in Asan were higher than those in Seoul, suggesting that yellow dust in spring could affect $PM_{2.5}$ concentrations in Asan rather than Seoul. The correlation coefficients of Pb and Zn were 0.343 for Asan and 0.813 for Seoul during non-yellow dust condition, suggesting that Pb and Zn were influenced with the same sources. The correlation coefficients between Si and Fe in the fine particulate mode were 0.999 (Asan) and 0.998 (Seoul) during yellow dust condition. It was suggested that these two elements were impacted by soil-related transport from China during the yellow dust storm condition.