• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.1-10
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• 1998

Relationships between TSP and PM10 concentrations were evaluated using their respective data sets collected from Taegu and Kyeungsan areas during the period of December 1993 to November 1994. The collection of data was made using the gravimetric and $\beta$-ray absorption ($\beta$-MPM) methods for 7 days of every month from three urban sites in Taegu and one suburban site in Kyeungsan. Correlation coefficients between TSP and PM10 concentrations for these four sampling sites were found in the range of 0.85 $\sim$ 0.96. Correlation analysis was also conducted for $\beta$-PM concentration data that were measured only from the residential and commercial sites. The correlation coefficients between TSP and $\beta$-PM concentrations were 0.9 in the residential site and 0.8 in the commercial site. By contrast, the correlation coefficients between PM10 $\beta$-PM concentrations were almost identical for both the residential and commercial sites with a value of 0.88. The mean ratio for PM10 to TSP concentrations for all sites was appeared to be 0.68. The analysis of seasonal trends in PM10/TSP ratios showed that the contribution of PM10 to TSP concentrations was more significant during winter (0.70 $\sim$ 0.75) than during summer (0.61 $\sim$ 0.68). The results of this study may provide empirical informations on the compatability of aerosol data measured by different sampling methods.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.4
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• pp.317-325
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• 2002

An air pollution monitoring station has been operated at Tokchok Island since April 1999 to characterize the background atmosphere in the vicinity of the Yellow Sea. In this study, eight chemical species in PM$_{2.5}$ and three gaseous species were analyzed. A total of 53 samples were collected for the analysis of PM$_{2.5}$ and gaseous species from April, 1999 to April, 2001. The overall mean mass concentration of PM$_{2.5}$ was 20.8 $\mu\textrm{g}$/㎥ and the eight soluble ionic species accounted for about 46.8% of PM$_{2.5}$ mass. Approximately 80% of samples appeared to experience the chloride loss effect. Air pollutant sources of PM$_{2.5}$ measured at Tokchok Island were qualitatively identified by the principal component analysis. It was found that five principal components are secondary aerosol, soil, incineration, phase change of nitrate, and ocean.and ocean.

• Journal of Environmental Health Sciences
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• v.29 no.4
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• pp.10-16
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• 2003

Atmospheric samples were conducted from September 2001 to July 2002 with GPS-l PUF sampler in rural site to concentration distributions of gas/particle PCBs and to calculate dry deposition flux of PCBs. $\Sigma$PCBs concentrations of gas/particle PCBs were 59.29$\pm$48.83, 6.56$\pm$6.59 pg/㎥, respectively. Gas contribution (%) of total PCBs (gas + particle) was 90% which existed gas phase in the atmosphere. The particle contribution (%) of PCB congeners increased relatively more of the less volatile congeners with the highest chlorine number. The correlation coefficients (r) between total PCBs and temperature ($^{\circ}C$) showed negative correlation in - 0.62 (p<0.0l) for particle phase, positive correlation in 0.63 (p<0.01) for gas phase. In other word, particle phase PCBs is enriched in colder weather which could be due to greater in corporation of condensed gas phase at low temperature. The calculated dry deposition of total PCBs (gas + particle) was 0.008, 0.008 $\mu\textrm{g}$ $m^{-2}$ da $y^{-l}$ which showed maximum dry deposition flux in December, minimum data in July Bs in the atmosphere. The calculated dry deposition fluxes of total PCBs were influenced by particle phase PCBs even though PCBs in the atmosphere were present primarily in the gas phase.e.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1879-1887
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• 2013

To investigate the level of genotoxicity over Bangkok atmosphere, $PM_{10}$ samples were collected at the Klongchan Housing Authority (KHA), Nonsree High School (NHS), Watsing High School (WHS), Electricity Generating Authority of Thailand (EGAT), Chokchai 4 Police Station (CPS), Dindaeng Housing Authority (DHA) and Badindecha High School (BHS). For all monitoring stations, each sample covered a period of 24 hours taken at a normal weekday every month from January-December 2006 forming a database of 84 individual air samples (i.e. $12{\times}7=84$). Atmospheric concentrations of low molecular weight PAHs (i.e. phenanthrene, anthracene, pyrene and fluoranthene) were measured in $PM_{10}$ at seven observatory sites operated by the pollution control department of Thailand (PCD). The mutagenicity of extracts of the samples was compared in Salmonella according to standard Ames test method. The dependence of the effects on sampling time and on sampling location was investigated with the aid of a calculation of mutagenic index (MI). This MI was used to estimate the increase in mutagenicity above background levels (i.e. negative control) at the seven monitoring sites in urban area of Bangkok due to anthropogenic emissions within that area. Applications of the AMES method showed that the average MI of $PM_{10}$ collected at all sampling sites were $1.37{\pm}0.10$ (TA98; +S9), $1.24{\pm}0.08$ (TA98; -S9), $1.45{\pm}0.10$ (TA100; +S9) and $1.30{\pm}0.09$ (TA100; -S9) with relatively less variations. Analytical results reconfirm that the particulate PAH concentrations measured at PCD air quality monitoring stations are moderately low in comparison with previous results observed in other countries. In addition, the concept of incremental lifetime particulate matter exposure (ILPE) was employed to investigate the potential risks of exposure to particulate PAHs in Bangkok atmosphere.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.1
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.15-27
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• 2015

The collection of fine particulate matter samples was made at Gosan site of Jeju Island, one of the background sites of Korea, during a year of 2013, and their water-soluble ionic species were analyzed in order to examine the chemical compositions and pollution characteristics. The concentrations of $nss-SO_4{^{2-}}$, $NH_4{^{+}}$, $NO_3{^{-}}$, and $K^+$ had occupied 66.0% of water-soluble ionic species in $PM_{10}$, especially 94.3% in $PM_{2.5}$ fine mode, however the $nss-Ca^{2+}$ and $Na^+$ showed high concentrations in $PM_{10-2.5}$ coarse mode. $NO_3{^-}/nss-SO_4{^{2-}}$ concentration ratios in $PM_{10}$ and $PM_{10-2.5}$ were 0.30 and 0.13, showing less significant effect from automobile and local pollution sources. The sulfate and nitrate compounds were presumed to be long-range transported to Gosan area by the relatively high SOR and NOR values. The trajectory cluster analysis showed the higher concentrations of the major secondary pollutants ($nss-SO_4{^{2-}}$, $NO_3{^{-}}$, $NH_4{^{+}}$) and $nss-Ca^{2+}$ when the air masses had moved from China continent and Korean peninsula into Gosan area.

• Journal of environmental and Sanitary engineering
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• v.20 no.4 s.58
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• pp.9-20
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• 2005

The purpose of the study was characteristics of secondary pollutants of $PM_{10}$ collected in pocheon between August 2002 and June 2003. The ambient concentrations of $PM_{10}$ mass, 9 water-soluble anions and cations, and 13 bulk composition trace elements were determined from filter samples collected by $PM_{10}$ high volume air sampler(UV-15H, Graseby-Anderson Co., USA). During this period average $PM_{10}$ mass concentration was $83.8{\mu}g/m^3(49.8{\mu}g/m^3\~111.6{\mu}g/m^3)$ in Pocheon. Mechanism for transformation of secondary pollutants by soluble ion components is divided into two categories; $NaNO_3$ type by the reaction of sea salt and $HNO_3$ in the atmosphere, and nitrate salt or phosphate salt type such as $(NH_4)_2SO_4,\;NH_4NaSO_4,\;and\;(NH_4)_2SO_4(2NH_4O_3)$.

• Asian Journal of Atmospheric Environment
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• v.12 no.3
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• pp.244-254
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• 2018

Ulaanbaatar, the capital of Mongolia, is subject to high levels of atmospheric pollution during winter, which severely threatens the health of the population. By analyzing surface meteorological data, ground-based LIDAR data, and radiosonde data collected from 2008 to 2016, we studied seasonal variations in particulate matter (PM) concentration, visibility, relative humidity, temperature inversion layer thickness, and temperature inversion intensity. PM concentrations started to exceed the 24-h average standard ($50{\mu}g/m^3$) in mid-October and peaked from December to January. Visibility showed a significant negative correlation with PM concentration. Relative humidity was within the range of 60-80% when there were high PM concentrations. Both temperature inversion layer thickness and intensity reached maxima in January and showed similar seasonal variations with respect to PM concentration. The monthly average temperature inversion intensity showed a strong positive correlation with the monthly average $PM_{2.5}$ concentration. Furthermore, the temperature inversion layer thickness exceeded 500 m in midwinter and overlaid the weak mixed layer during daytime. Radiative cooling enhanced by the basin-like terrain led to a stable urban atmosphere, which strengthened particulate air pollution.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.329-337
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• 1991

The Ni-MgO composites were prepared by coprecipitation of NiO-MgO solid solutions and their selective reduction in a hydrogen atmosphere. We report on the measurements of both ac conductivity $\sigma$ ($\omega$, f) and dielectric constant $textsc{k}$'($\omega$, f) for the Ni-MgO composites in the frequency range from 10 Hz to 10 MHz at room temperature. The frequency exponents of conductivity and dielectric constant, x and y, are found to be x=0.98$\pm$0.05 and y=0.05$\pm$0.01. These results are in good agreement with a general scaling relation $\chi$-y=1, although these values are different from the theoretical predications. The dielectric constant exponent ($textsc{k}$' f-fc -s) is found to be s=0.62$\pm$0.07 with estimated percolation threshold fc=0.20$\pm$0.02.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.357-363
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• 1994

To investigate the effect of extracellular matrix proteins on the in vitro development of blastomeres isolated from 2, 4, and 8-cell embryos(termed 1/2, 1/4 and 1/8 blastomeres, respectively) of ICR strain mice, those were cultured in fibronectin, gelatin, or collagen precoated culture dishes containing 1.5ml of NaHCO3-BMOC-3 medium at 37$^{\circ}C$ for 72 hrs, under the atmosphere at 5% CO2. and 95% air. Fibronectin, gelatin, or collagen significantly(P<0.01) increased and blastocyst formation rate compared with controls in 1/2(65.3, 59.2, 60.7% vs. 21.6%), 1/4(63.7, 53.4, 57.1% vs. 26.3%), and 1/8 blastomeres(61.1, 52.3, 53.7% vs. 19.1%). Both the nuclear number(P<0.05) and diameter of blastocysts(P<0.01) developed from balstomeres were significantly affected by the origin of blastomeres. The nuclear number of blastocysts developed from 1/2, 1/4, and 1/8 blastomeres ranged 29.3$\pm$1.6, 24.5$\pm$1.3, and 20..$\pm$1.2, respectively. And the diameter of those blastocysts was 88.3$\pm$2.4, 57.6$\pm$2.1, 39.8$\pm$1.9${\mu}{\textrm}{m}$, respectively.