• Journal of Environmental Science International
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• v.23 no.7
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• pp.1241-1251
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• 2014

The study investigates weekday/weekend characteristics of $PM_{10}$ and $PM_{2.5}$ concentrations and meteorological elements in Busan. The $PM_{10}$ concentration is highest on Wednesday and Thursday, and lowest on Sunday. On the other hand, the $PM_{2.5}$ concentration is highest on Wednesday and lowest on Sunday. The location where concentrations of weekdays and weekend differ the most is Hwakjang-dong, the industrial area, and where they differ the least is Gijang-up and Joa-dong, the residential area. Fine particle concentration in the industrial area was consistent at dawn and in the morning, but varied in the afternoon and at night. The visibility of Sunday was 0.49 km higher than that of weekdays, and the solar radiation of Sunday was $0.11MJ/m^2$ higher than that of weekdays. These results indicate that the concentration of fine particles had influence on the change of visibility and solar radiation.

• Journal of environmental and Sanitary engineering
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• v.23 no.1
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• pp.33-48
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• 2008

The purpose of this study was to characterize background mass concentration of $PM_{10},\;PM_{2.5}$ and metallic composition from June 2004 to June 2005 in comparison with Seoul and Asan city. The results were as follows: 1. Annual mean of $PM_{10}$ concentrations in Seoul and Asan were $56.95({\pm}25.63){\mu}g/m^3,\;57.02({\pm}27.22){\mu}g/m^3$ respectly. 2. Annual mean of $PM_{2.5}$ concentrations in Seoul and Asan were $46.97({\pm}40.36){\mu}g/m^3,\;42.16({\pm}21.79){\mu}g/m^3$ respectly. 3. The average $PM_{2.5}/PM_{10}$ ratio was 0.82 in Seoul and 0.74 in Asan city. 4. The concentration of $PM_{10},\;PM_{2.5}$ were the highest in spring and the lowest in summer. Asan was higher than Seoul in spring and summer. 5. The results showed that average $PM_{10}$ composition order as Si>Fe>Pb>Zn>Mn in Seoul and Si>Fe>Zn>Pb>Mn in Asan. The concentration of metals in $PM_{10}$ of Seoul that Cr, Cu, Fe, Mn were high in spring and Zn was low in Fall. Fe, Mn were high in spring of Asan. 6. The results showed that average $PM_{2.5}$ composition order as Si>Pb>Fe>Zn>Mn in Seoul and Si>Fe>Pb>Zn>Cr in Asan. The concentration of metals in $PM_{2.5}$ of Seoul that Cr was high in spring. 7. The result showed that relation between Cr and Cu, Cu and Fe, Fe and Mn, Mn and Zn, Zn and Si in Seoul, Cr and Zn, Cu and Pb, Zn and Pb, Pb and Mn in Asan. The result showed that $PM_{10}$ concentration exceeding $50{\mu}g/m^3$(US-EPA Standard) and $PM_{2.5}$ concentration exceeding $15{\mu}g/m^3$(US-EPA Standard). In urban area, the monitoring of $PM_{2.5}$ permits the anthropogenic sources and the interference of natural sources with respect to $PM_{10}$ measurements.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.227-232
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• 1991

The pathogenicity of entomopathogenic nematodes Sfeinernema earpocapsae and Heferorhabditis baeferiophora was evaluated against forest insect pests, alder leaf beetle Agelastiea eoerulea, pellucid zygaenid Pryeria siniea, and box-tree pyralid Glyphodes perspeetalis. Alder leaf beetle larvae were exposed to S. earpocapsae at concentration of 0, 25, 50, and 100 nematodes and to H. baeferiophora at concentration of 0, 10, 20, and 40 nematodes per larva on alder leaves. Mortalities of 1st instar lavae were 85.4 $\pm$ 4.1-100%, 2nd instar larvae 80.0 $\pm$ 5.8-100%, and 3rd instar larvae 65.0 $\pm$ 10.8-100% in S. earpocapsae and those of 1st instar larvae were 82.5 $\pm$ 6.9-100%, 2nd instar larvae 77.5 $\pm$ 4.7-100%, and 3rd instar larvae 55.0 $\pm$ 13.5-100% in H. baeferiophora treatment. When pellucid zygaenid larvae were exposed to S. earpocapsae at concentration of 0, 5, 10, 20, 40, and 80 nematodes and to H. baeteriophora at concentration of 0, 2, 5, 10,20, and 40 nematodes per larva, mortalities were 98.9 $\pm$ 1.1-100% in S. earpocapsae and 26.7 $\pm$ 5.1-74.5 $\pm$ 6.2% in H. baeferiophora. The mortalities of box-tree pyralid larvae were 97.8 $\pm$ 1.5-100% in S. earpocapsae treated with concentration of 0,20,40, and 80 nematodes per larva and those were 92.0 $\pm$ 6.2-98.9 $\pm$ 1.1 % in H. baeferiophora treated with con'||'&'||'not;centration of 0, 10, 20, and 40 nematodes per larva.

• Particle and aerosol research
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• v.6 no.1
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• pp.9-20
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• 2010

This study examined the concentration level of the major air pollutants in public transportation. The study was conducted between February 2009 and March 2008 at Suwon-Yeosu line in Korea. $PM_{10}$ concentration level was $100{\mu}g/m^3$ on average. The $PM_{2.5}$ to PM10 ratio in transport is 0.37, which was lower than the results published by other researches. The result also demonstrated that outdoor $PM_{10}$ concentration was about 56~60% level compared to that of the cabin. $CO_2$ concentration level in the cabin was 1,359ppm, which does not exceed 2,000ppm, which is the guideline concentration level according to the Ministry of Environment. $CO_2$ concentration level in the cabin was $CO_2=23.4{\times}N+460.2$, and about 23.4ppm in $CO_2$ concentration level increased every time one passenger was added on. The experiment conducted on the train demonstrated that the average $PM_{10}$ concentration level was $100{\mu}g/m^3$ in case of the reference cabin while average $PM_{10}$ concentration level of the modified vehicle was $68{\mu}g/m^3$. Likewise, effect of the particle reduction device for the reduction of $PM_{10}$ concentration level was approximately 21%. Meanwhile there was almost no difference in the concentration level between reference and modified cabin in case of $PM_{2.5}$. Using zeolite as an adsorbent was made to reduce the $CO_2$ concentration level in the cabin. Number of passengers was factored in, to calculate the effect of the adsorption device, which demonstrated that about 36% of $CO_2$ concentration level was reduced in the modified cabin effect of the $CO_2$ reduction device. This research analyzed the current status concerning the quality of air in the public transportation and technologies were developed that reduces major air pollutants.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.119-128
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• 2004

The nitrate concentrations in PM$_{2.5}$ and TSP measured at Gosan, Jeju Island, Korea, between March 1998 and February 2002, are discussed. Especially, the characteristics of high nitrate concentration days were analyzed. High nitrate concentration cases in PM$_{2.5}$ were highly correlated with anthropogenic species such as NH$_4$$^{[-10]}$ , and high nitrate concentration cases in TSP were highly correlated with crustal species such as nss-Ca$^{2+}$ and nss -Mg$^{2+}$ Backward trajectory analysis results show the cases of high correlation between nitrate and anthropogenic species occurred when the air parcels moved from China, and the cases of high correlation between nitrate and crustal species occurred when the air parcels moved from Mongolia. Also, high nitrate concentration cases occurred most often in spring (65%) when the air parcels moved from Mongolia and China.ina.

• Asian Journal of Atmospheric Environment
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• v.10 no.1
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• pp.1-12
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• 2016

Numerous researchers have proposed that surface area is a more appropriate indicator than mass for evaluating pulmonary inflammatory responses caused by exposure to fine and ultrafine particles. In this study, measurements of surface area concentrations of aerosols were conducted in Yokohama, Japan, using the diffusion charging method. $PM_{2.5}$ mass concentration and black carbon concentration in $PM_{2.5}$ were also measured. The 24-hour continuous measurement campaigns were conducted 39 times from March to November, 2014. The surface area concentration was more closely correlated with the black carbon concentration than with the $PM_{2.5}$ mass concentration. It is considered that the abundance of black carbon particles significantly affects the surface area concentration of $PM_{2.5}$. The strength of the correlation between the surface area and black carbon concentrations varied considerably among the measurement campaigns. A relatively weaker afternoon correlation was observed compared with the other time zones (morning, evening, and night). We consider that these phenomena are due to the transportation/formation of the particles other than black carbon that affects surface area concentration and/or the variation of the surface condition of the black carbon particles.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1355-1367
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• 2007

This study summarizes the relations among $PM_{2.5}$ concentration, water-soluble ions concentration, metallic element Components characteristics and SPSS in negative ion and metallic element of $PM_{2.5}$ particle in Miryang.(By the urban area, the industrial complex area and the suburban area according to the season) $PM_{2.5}$ concentration of total 72 samples collected from 3 sites turned out to range from 3.47 to 34.7 ${\mu}g/m^3$, and the average concentration was the suburban area-the kin nup(16.00 ${\mu}g/m^3$) > the urban area-the roof of the old Miryang university(10.32 ${\mu}g/m^3$) > the industrial complex-Sapo industrial complex(10.29 ${\mu}g/m^3$). In particular, the suburban area had $PM_{2.5}$ concentration 1.5 times those of urban area, industrial complex. It was thought although the site was suburban and farm-side without pollutants around, it had a higher concentration value influenced by external factors including the brickyard, small-scale incinerator, driving range construction, construction on the Daegu-Busan express and the widening of the four-lane road between Miryang-Anyang nearby. As for water-soluble ions among $PM_{2.5}$ particle collected in Miryang area, $SO4_{2^-}$ accounted for 60% and $NO_{3^-}$, was 30% in spring and summer. And $NO_{3^-}$ accounted for 50% and $SO4_{2^-}$ was 35% in fall and winter. The AI value of metallic Components among $PM_{2.5}$ particle collected in Miryang area had a high value influenced by the apartment complex construction and the extension work of road. The industrial complex area had Zn concentration 3 times, and Fe concentration 2 times those of urban area and suburb area. When it comes to the relation with metallic elements in urban area, the highest coefficient of correlation was between Cr-Fe with 0.85, and Pb-Cd turned out in the reverse correlation. Among metallic elements, the coefficients of correlation between Zn and Cr, Mn, Fe, NI were high in industrial complex area. The highest coefficient of correlation was between Mn-Zn with 0.88, meanwhile Ni and Cu, Cd turned out in the reverse correlation in the suburb area. These coefficients of correlation are attributed to the difference in pollutant sources, rather than difference in pollutant and non-pollutant.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1111-1115
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• 2008

The characterization of PM$_{2.5}$ and PM$_{10}$ concentration is considered by analysis of ionic and heavy metal component to measured suspended particle at atmosphere in Hoseo university of Asan area. The variation of concentration is studied at the periods of asian dust occured. In asian dust, the PM$_{2.5}$ ratio is decreased from 79.7% to 40.1%, whereas the size-classified mean concentration of suspended particle is increased largely. It is found that the PM$_{2.5}$ ratio is decreased relatively because the coarse particle is increased largely according to the analysis of the mass concentration to divide the fine and coarse particle on 2.1 $\mu$m basis. It is observed that the Ca$^{2+}$ion is about 40 magnifications and Na$^+$, SO$_4{^{2-}}$ ion is increased in sequence in coarse particle, whereas the variation of ionic concentration is slightly increased in the fine particle. Furthermore, Mn, Fe, Zn, and Al are increased in sequence as the result of heavy metal component analysis, and Al is shown the most increased as mass concentration.

• 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 the Korean Society of Safety
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• v.32 no.5
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• pp.157-167
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• 2017

Millions of People die every year from diseases caused by exposure to outdoor air pollution. Especially, one of the most severe types of air pollution is fine particulate matter (PM10, PM2.5). South Korea also has been suffered from severe PM. This paper analyzes regional risks induced by PM10 and PM2.5 that have affected domestic area of Korea during 2014~2016.3Q. We investigated daily maxima of PM10 and PM2.5 data observed on 284 stations in South Korea, and found extremely high outlier. We employed extreme value distributions to fit the PM10 and PM2.5 data, but a single distribution did not fit the data well. For theses reasons, we implemented extreme mixture models such as the generalized Pareto distribution(GPD) with the normal, the gamma, the Weibull and the log-normal, respectively. Next, we divided the whole area into 16 regions and analyzed characteristics of PM risks by developing the FN-curves. Finally, we estimated 1-month, 1-quater, half year, 1-year and 3-years period return levels, respectively. The severity rankings of PM10 and PM2.5 concentration turned out to be different from region to region. The capital area revealed the worst PM risk in all seasons. The reason for high PM risk even in the yellow dust free season (Jun. ~ Sep.) can be inferred from the concentration of factories in this area. Gwangju showed the highest return level of PM2.5, even if the return level of PM10 was relatively low. This phenomenon implies that we should investigate chemical mechanisms for making PM2.5 in the vicinity of Gwangju area. On the other hand, Gyeongbuk and Ulsan exposed relatively high PM10 risk and low PM2.5 risk. This indicates that the management policy of PM risk in the west side should be different from that in the east side. The results of this research may provide insights for managing regional risks induced by PM10 and PM2.5 in South Korea.