• Land and Housing Review
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• v.12 no.3
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• pp.39-50
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• 2021

This research aims to provide guidelines with the appropriate type of smart bus stop to reduce the concentration of fine dust. To this end, we divided smart bus stops into two types: closed and open bus stops. The estimated reduction effect was compared and analysed by measuring the estimated PM₁₀ and the estimated PM_2.5 at five locations inside and outside a smart bus stop located in Gangnam gu, Seoul. The effect of reducing the amount of the fine dust concentration in external space was insignificant for both types of bus stops. The different effect of reducing the concentration of the amount between in internal space was relatively significant: the fine dust concentration was 26.0 ㎍/m³ for PM₁₀ and 20.2 ㎍/m³ for PM_2.5 at open-type bus stops; whilst was 2.4 ㎍/m³ for PM₁₀ and 1.8 ㎍/m³ for PM_2.5 at closed type bus stops. Based on the findings, a closed type bus stop is recommended when considering the cost of reducing fine dust. In addition, due to the ineffectiveness of reducing the amount of fine dust from the outside of the bus stop, additional provision of smart bus stops is required particularly in locations where demand exceeds the capacity of the inside. A clear definition of smart bus stop and it's minimum standard should also be considered.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.533-539
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• 2007

The research was conducted to simulate and interpret the change of $PM_{10}$ profile by Asian dust using the CALPUFF modeling system for the period April 6 through 18, 2001. The results, which are represented a daily variation of $PM_{10}$ concentration before and after Asian dust, was located between a minimum concentration of $50{\mu}g/m^3$ and a maximum concentration of $100{\mu}g/m^3$, Most concentration peaks in the $PM_{10}$ profile were shown within a level below 500 m and had a pattern that rapidly increased up the peak and decreased after the peak to 1000 m. Even though the shapes of the vertical profile during Asian dust days were similar to non-Asian dust days, no rapid change vertically was observed. In particular, the vertical profile on 1200 LST and 1800 LST was noticeably shifted to the higher concentrations, which means $PM_{10}$ in the atmosphere was changed into a vertically and horizontally heterogeneous form under the Asian dust event. Finally, it is con-firmed that the simulation result from CALPUFF might schematically sketched atmospheric $PM_{10}$ profiles and their change by Asian dust throughout the comparison with profiles of aerosol extinction coefficients, which were acquired from Lidar measurement at KGAWO.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.6
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• pp.666-682
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• 2010

The forecasting system for Today's and Tomorrow's PM10 was developed based on the statistical model and the forecasting was performed at 9 AM to predict Today's 24 hour average PM10 concentration and at 5 PM to predict Tomorrow's 24 hour average PM10. The Today's forecasting model was operated based on measured air quality and meteorological data while Tomorrow's model was run by monitored data as well as the meteorological data calculated from the weather forecasting model such as MM5 (Mesoscale Meteorological Model version 5). The observed air quality data at ambient air quality monitoring stations as well as measured and forecasted meteorological data were reviewed to find the relationship with target PM10 concentrations by the regression analysis. The PM concentration, wind speed, precipitation rate, mixing height and dew-point deficit temperature were major variables to determine the level of PM10 and the wind direction at 500 hpa height was also a good indicator to identify the influence of long-range transport from other countries. The neural network, regression model, and decision tree method were used as the forecasting models to predict the class of a comprehensive air quality index and the final forecasting index was determined by the most frequent index among the three model's predicted indexes. The accuracy, false alarm rate, and probability of detection in Tomorrow's model were 72.4%, 0.0%, and 42.9% while those in Today's model were 80.8%, 12.5%, and 77.8%, respectively. The statistical model had the limitation to predict the rapid changing PM10 concentration by long-range transport from the outside of Korea and in this case the chemical transport model would be an alternative method.

• Development and Reproduction
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• v.17 no.4
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• pp.345-351
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• 2013

This study examines the effects on fertilization rate (FR), hatching rate (HR), and normal individual rate after artificial fertilization using frozen thawed sperm according to the cryoprotectant (DMSO) concentration and the period of cryopreserved sperm of longtooth grouper, Epinephelus bruneus. Performing artificial fertilization using frozen-thawed sperm, after freezing the sperm at different DMSO concentration of 5.0%, 7.5%, 10.0% respectively, FR were (DMSO 5.0%: $99.5{\pm}0.8%$, DMSO 7.5%: $99.5{\pm}0.7%$, and DMSO 10.0%: $99.6{\pm}0.6%$). The results are not significantly different from the control fresh sperm (100%). HR also (DMSO 5.0%: $96.2{\pm}2.3%$, DMSO 7.5%: $95.3{\pm}3.6%$, 10.0%: $96.6{\pm}1.8%$) were not significantly different in each group. The normal individual rate after hatching using with control fresh sperm ($98.4%{\pm}0.5$) and DMSO concentration level of 5.0% ($97.8{\pm}0.1%$) were not significantly different. However, with 7.5% ($97.2{\pm}0.6%$) and 10.0% DMSO concentrations ($95.9{\pm}0.2%$) are lower than the normal individual rate after hatching observed in the control and 5.0% DMSO. Performing artificial fertilization using frozen-thawed sperm at different frozen period (2 days, 2 years, and 3 years), 10% DMSO FR and HR of 3 years (FR; $66.8{\pm}1.8%$, HR: $82.0{\pm}12.9%$) and 2 years (FR; $78.5{\pm}14.8%$, HR: $79.3{\pm}0.6%$) cryopreserved sperm were lower than control (FR; 100%, HR: $91.1{\pm}3.6%$) and 2 days cryopreserved sperm (FR; $99.6{\pm}0.6%$, HR: $96.6{\pm}1.8%$). These results suggest suitable DMSO concentration ranges of cryopreservation sperm for E. bruneus is 5 to 10% and with 2 to 3 years cryopreservation period, cryopreservation sperm can be useful for seed production.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.300-310
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• 2008

In order to further determine the mass concentration and ion composition of size-segregated particulate matter (PM) during the non-Asian dust storm of spring, $PM_{2.5}$ (fine particle), $PM_{10-2.5}$ (coarse particle), and $PM_{over-10}$ (PM with an aerodynamic diameter larger than $10{\mu}m$) were collected using a MCI (multi-nozzle cascade impactor) sampler of a three-stage filter pack in the spring season of 2007 in the Iksan area. During the sampling period from 5 April to 21 April, a total of 34 samples for size-segregated PM were collected, and then measured for PM mass concentrations by gravimetric measurements and for water-soluble inorganic ion species by using ion chromatography. Average mass concentrations of $PM_{2.5}$, $PM_{10-2.5}$, $PM_{over-10}$ were $35.4{\pm}11.5{\mu}g/m^3$, $13.3{\pm}5.5{\mu}g/m^3$ and $9.5{\pm}4.7{\mu}g/m^3$, respectively. On average, $PM_{2.5}$ accounted for 74% of $PM_{10}$. Compared with the literature from other areas in Korea, the measured concentration of $PM_{2.5}$ were relatively high. Water-soluble inorganic ion fractions in $PM_{2.5}$, $PM_{10-2.5}$, and $PM_{over-10}$ were found to be 47.8%, 28.5%, and 14.7%, respectively. Among the water-soluble inorganic ion species, $SO_4^{2-}$, $NO_3^-$ and $NH_4^+$ were the main components in $PM_{2.5}$, while $NO_3^-$ dominantly existed in both $PM_{10-2.5}$ and $PM_{over-10}$. Non-seasalt $SO_4^{2-}$ (nss-$SO_4^{2-}$ and $NO_3^-$ were found to mainly exist as the neutralized chemical components of $(NH_4)_2SO_4$ and $NH_4NO_3$ in fine particles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.907-923
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• 2020

For the severe haze situation in the Beijing-Tianjin-Hebei region, conventional fine particulate matter (PM2.5) concentration prediction methods based on pollutant data face problems such as incomplete data, which may lead to poor prediction performance. Therefore, this paper proposes a method of predicting the PM2.5 concentration based on image analysis technology that combines image data, which can reflect the original weather conditions, with currently popular machine learning methods. First, based on local parameter estimation, autoregressive (AR) model analysis and local estimation of the increase in image blur, we extract features from the weather images using an approach inspired by free energy and a no-reference robust metric model. Next, we compare the coefficient energy and contrast difference of each pixel in the AR model and then use the percentages to calculate the image sharpness to derive the overall mass fraction. Furthermore, the results are compared. The relationship between residual value and PM2.5 concentration is fitted by generalized Gauss distribution (GGD) model. Finally, nonlinear mapping is performed via the wavelet neural network (WNN) method to obtain the PM2.5 concentration. Experimental results obtained on real data show that the proposed method offers an improved prediction accuracy and lower root mean square error (RMSE).

• Journal of Environmental Science International
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• v.32 no.8
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• pp.521-531
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• 2023

This study analyzed the impact of recirculation on high-concentration PM_2.5 in the coastal area. Through the analysis of observational data, it was observed that the development of sea breeze led to an increase in PM_2.5 and SO₄^2- concentrations. Hysplit backward trajectory analysis confirmed the occurrence of air mass recirculation. Results from WRF and CMAQ numerical simulations indicated that pollutants transported from land to sea during the night were re-transported to the land by daytime sea breeze, leading to high-concentration PM_2.5 in Busan. To quantitatively investigate the recirculation a recirculation factor (RF) was calculated, showing an increase in RF values during high-concentration PM_2.5 episodes. However, the RF values varied slightly depending on the time resolution of meteorological data used for the calculations. This variation was attributed to the terrain characteristics at observation sites. Additionally, during long-range transported days leading to nationwide high-concentration PM_2.5 events, synoptic-scale circulation dominated, resulting in weaker correlation between PM_2.5 concentration and RF values. This study enhances the understanding of the influence of recirculation on air pollution. However, it is important to consider the impact of temporal resolution and terrain characteristics when using RF for evaluating recirculation during episodes of air pollution.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.133-145
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• 2001

The receptor modeling is one of the statistical methods to achieve reasonable air pollution strategies. The pur-pose of this study was to survey the concentration variability oi inorganic elements and ionic species in the PM-10 particles, to qualitatively characterize emission sources by an advanced algorithm called positive matrix factoriza-tion(PMF) as a receptor model that can strictly provide results in every loading matrix. A total of 254 samples was collected by a PM-10 high volume air sampler from Mar. 1997 to Feb. 1998 in Kyung Hee University at Suwon Campus. Fourteen chemical species(Zn, Cu, Fe, Pb, Al, Mn, $Na^{+}$, NH$_4$+, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, $SO_4^{2-}$, $NO_{3}^{-}$, and $Cl^{-}$) were determined by AAS and IC methods. The study results showed that the average monthly concentration of PM-10 particles were 86.3$\mu\textrm{g}$/$\textrm{m}^3$ in March (maximum) and 28.5$\mu\textrm{g}$/$\textrm{m}^3$ in August(minimum), respectively. The concentrations of Na+, NH$_4$+, $K^{+}$ and $Cl^{-}$ in winter, $Mg^{2+}$, $Ca^{2+}$ and $NO_{3}^{-}$, in spring, and $SO_4^{2-}$ in summer showed the largest peak concentration for the respective season. Through and app-lication of a PMF program of Pm-10 concentration data of Suwon, 9 sources were qualitatively identified , such as incineration source, oil burning source, soil related source, open burning source automobile source, coal burning sources, secondary sulfate related source, and secondary nitrate related source.

• Particle and aerosol research
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• v.4 no.1
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• pp.1-7
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• 2008

Temporal trends of the PM10 and PM2.5 mass concentrations, and the concentrations of chemical species (sulfate, nitrate, ammonium, OC, and EC) in PM2.5 at Seoul are compared with the reported results from other mega cities in the world. The mass concentrations of PM10 and PM2.5 at Seoul show decreasing trend. However, the concentration levels are still higher than other cities except Beijing. The sulfate concentration at Seoul has decreased while those of nitrate and ammonium have increased. The concentrations of OC and EC show no apparent trend.

• Journal of Environmental Science International
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• v.23 no.12
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• pp.1963-1970
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• 2014

Ambient particulate matters($PM_{10}$ and $PM_{2.5}$) were investigated at GNTECH university in Jinju city. Samples were collected using a dichotomous sampler(series 240, Andersen Corp.) and a TEOM(Tapered Element Oscillating Microbalance) monitor period from November 2012 to October 2013. For the dichotomous sampler measurements, daily 24-h integrated $PM_{2.5}$ and $PM_{10-2.5}$ ambient air samples were collected at a total flow rate of 16.7 L /min. For the TEOM monitor measurements, daily 1-h integrated $PM_{10}$ ambient air samples were collected at a flow rate of 16.7 L /min. The annual average concentrations of $PM_{10-2.5}$ and $PM_{2.5}$ by a dichotomous sampler were $10.0{\pm}6.1{\mu}g/m^3$ and $22.6{\pm}9.3{\mu}g/m^3$, respectively. And $PM_{10}$ concentration by dichotomous sampler were similar to TEOM monitor by $32.7{\pm}12.9{\mu}g/m^3$ and $31.7{\pm}11.3{\mu}g/m^3$, respectively. And good correlation ($R^2=0.964$) between the two methods was observed. The annual average of $PM_{2.5}/PM_{10}$ ratio was $0.70{\pm}0.12$.