• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.642-655
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• 2013

In this study, semi-continuous measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), black carbon (BC), and ionic species concentrations were made for the period of April 03~13, 2012, at a South Area Supersite at Gwangju. Possible sources causing the high concentrations of major chemical species in $PM_{2.5}$ observed during a haze episode were investigated. The measurement results, along with meteorological parameters, gaseous pollutants data, air mass back trajectory analyses and PSCF (potential source contribution function) results, were used to study the haze episode. Substantial enhancements of OC, EC, BC, $K^+$, $SO{_4}^{2-}$, $NO{_3}{^-}$, $NH{_4}{^+}$, and CO concentrations were closely associated with air masses coming from regions of forest fires in southeastern China, suggesting likely an impact of the forest fires. Also the PSCF maps for EC, OC, $SO{_4}^{2-}$, and $K^+$ demonstrate further that the long-range transport of smoke plumes of forest fires detected over the southeastern China could be a possible source of haze phenomena observed at the site. Another possible source leading to haze formation was likely from photochemistry of precursor gases such as volatile organic compounds, $SO_2$, and $NO_2$, resulting in accumulation of secondary organic aerosol, $SO{_4}^{2-}$ and $NO{_3}{^-}$. Throughout the episode, local wind directions were between 200 and $230^{\circ}C$, where two industrial areas are situated, with moderate wind speeds of 3~5 m/s, resulting in highly elevated concentration of $SO_2$ with a maximum of 15 ppb. The $SO{_4}^{2-}$ peak occurring in the afternoon hours coincided with maximum ambient temperature ($24^{\circ}C$) and ozone concentration (~100 ppb), and were driven by photochemistry of $SO_2$. As a result, the pattern of $SO{_4}^{2-}$ variations in relation to wind direction, $SO_2$ and $O_3$ concentrations, and the strong correlation between $SO_2$ and $SO{_4}^{2-}$ ($R^2=0.76$) suggests that in addition to the impact of smoke plumes from forest fires in the southeastern China, local $SO_2$ emissions were likely an important source of $SO{_4}^{2-}$ leading to haze formation at the site.

• Environmental Engineering Research
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• v.12 no.4
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• pp.176-193
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• 2007

The ability to measure groundwater contaminant flux is increasingly being recognized as crucial in order to prioritize contaminated site cleanups, estimate the efficiency of remediation technologies, measure rates of natural attenuation, and apply proper source terms to model groundwater contaminant transport. Recently, a number of methods have been developed and subsequently applied to measure contaminant mass flux in groundwater in the field. Flux measurement methods can be categorized as either point methods or integral methods. As the name suggests, point methods measure flux at a specific point or points in the subsurface. To increase confidence in the accuracy of the measurement, it is necessary to increase the number of points (and therefore, the cost) of the sampling network. Integral methods avoid this disadvantage by using pumping wells to interrogate large volumes of the subsurface. Unfortunately, integral methods are expensive because they require that large volumes of contaminated water be extracted and managed. Recent work has investigated the development of an integral method that does not require extraction of contaminated water from the subsurface. We begin with a review of the significance and importance of measuring groundwater contaminant mass flux. We then review groundwater contaminant flux measurement methods that are either currently in use or under development. Finally, we conclude with a qualitative comparison of the various flux measurement methods.

• Journal of Korean Society of Rural Planning
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• v.19 no.4
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• pp.137-147
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• 2013

Most of livestock houses are concentrated in certain area with mass rearing system resulting in rapid spread of infectious diseases such as HPAI (highly pathogenic avian influenza). The livestock-related vehicles which frequently travel between farms could be a major factor for disease spread by means of transmission of airborne aerosol including pathogens. This study was focused on the quantitative measurement of aerosol concentration by field experiment while vehicles were passing through the road. The TSP (total suspended particle) and PM10 (particle matter) were measured using air sampler with teflon filter installed downward the road with consideration of weather forecast and the direction of road. And aerosol spectrometer and video recorders were also used to measure the real-time distribution of aerosol concentration by its size. The results showed that PM2.5 was not considerable for transmission of airborne aerosol from the livestock-related vehicle. The mass generated from the road during the vehicle movement was measured and calculated to 241.4 ${\mu}g/m^3$ by means of the difference between TSP and PM2.5. The dispersion distance was predicted by 79.6 m from the trend curve.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.781-788
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• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• Journal of the Korean earth science society
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• v.31 no.3
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• pp.234-245
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• 2010

Twenty-four hour integrated $PM_{10}$ and $PM_{2.5}$ samples were measured during springtime (March, April, and May) in Busan for three years from 2006 to 2008, and mass concentrations and metallic elements of measurement were analyzed to investigate temporal, spatial, chemical characteristics of the mass concentration and metallic elements in association with meteorological conditions including Asian Dust (AD) vs. non Asian Dust (NAD) seasons, and other air mass transport patterns. The result showed that $PM_{10}$, $PM_{2.5}$ and $PM_{10-2.5}$ concentrations were on average of $126.2{\pm}89.8$, $85.5{\pm}41.6$, and $40.7{\pm}54.9{\mu}g/m^3$, respectively, and the $PM_{2.5}/PM_{10}$ and $PM_{10-2.5}/PM_{2.5}$ ratios were 0.70 and 0.48, respectively. The highest concentrations of PM were observed when air parcels were originated from both northwest sector covering Beijing and west sector including Shanghai areas.

• Asian Journal of Atmospheric Environment
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• v.6 no.3
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• pp.234-243
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• 2012

The wintertime high loading for atmospheric pollutants is certainly expected in the Byunsan Peninsula of Korea because of a great-scale reclamation project having construction of 33 km tidal sea dike impounding an area of over 40,000 ha and long-range transport. The goal of this study is to trace the origin of this wintertime burden for ambient particulate matter (hereafter called "PM") in the Byunsan Peninsula of Korea. The size-segregated (i.e., cutoff size from 0.01 ${\mu}m$ to 4.7 ${\mu}m$) PM sampling was conducted at a ground-based site of Byunsan Peninsula located in the west coast of Korean Peninsula during the height of dike constructing. Data archived in this study are the mass concentrations of ionic, elemental, and carbonic components in size-fractioned PM. The elemental mass of individual submicrometer particles was also analyzed. The sum of 5-source (i.e., elemental carbon, organic materials, inorganic secondary pollutants, crustal matter, and sea-salts) concentrations shows the bimodal distribution (major and minor peaks formed around $D_p$, 0.65 ${\mu}m$ and $D_p$, 4.7 ${\mu}m$, respectively) by border with 0.19 ${\mu}m$ of cutoff size. The concentrations of EC in $PM_{1.1-0.01}$ in winter and spring times were 4.62 ${\mu}g\;m^{-3}$ and 3.74 ${\mu}g\;m^{-3}$, respectively. Elemental masses of submicron individual particles are classified into two groups, i.e., the major elements (Cl, Al, Si, S, and P) and the minor trace elements. Cluster analysis differentiated the elements in submicron individual particles into 4-cluster. Among them, three clusters are in agreement with the major (Al, Si, S, and P), minor (Fe, Ca, and K), and trace compositions of coal burning. Meanwhile, Cl classified as an independent cluster has different source profile which was mainly due to the Saemangeum seawall project. Some highly toxic elements (e.g., Cr, Mn, and As (and/or Pb)) were also detected in some part of submicron individual PM. As a consequence, the combination of the Saemangeum project and winter monsoon played a considerable part in the double aggravation of wintertime air pollution in the Byunsan Peninsular.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.434-447
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• 2016

This study analyzed mass concentrations of PM10 and PM2.5, as measured at Tae-ahn and Gang-nae, Cheongju in central Korea over the period from 2011 to 2015. Higher mass concentrations of PM10, with the exception of dustfall cases during the period of winter and spring, reflected the influence of a prevailing westerly airflow, while the level of PM10 stayed at a low level in summer, reflecting the influence of North Pacific air mass and frequent rainfall. Accordingly, cases where a daily PM10 average of $81{\mu}gm^{-3}$ or over (exceeding the status of fine dust particles being 'a little bit bad') were often observed during the period of winter and spring, with more cases occurring in parts of Tae-ahn that are located close to the sources of pollutant emission in eastern China. Dustfall usually originated from dust storms made up of particles $2.5{\mu}m$ or over in diameter. However, anthropogenic haze displayed a high composition ratio of particulate less than $2.5{\mu}m$ in diameter. Accordingly, brightness temperature difference (BTD) values from the Communication, Ocean and Meteorological Satellite (COMS) were $-0.5^{\circ}K$ or over in haze with fine particulate. PM10 mass concentrations and NOAA 19 satellite BTD for haze cases were analyzed. Though PM10 mass concentrations were found to be lower than $200{\mu}g\;m^{-3}$, the mass concentration ratio of PM2.5/PM10 was measured as higher than 0.4 and BTD was found to be distributed in the range from -0.3 to $0.5^{\circ}K$. However, the BTD of dustfall cases exceeding $190{\mu}g\;m^{-3}$, were found to be less than 0.4 and BTD was found to be distributed in the range less than $-0.7^{\circ}K$. The result of applying BTD threshold values of the large-scale transport of haze proved to fall into line with the range over which aerosols of MODIS AOD and OMI AI were distributed.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.1
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• pp.99-106
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• 2006

Aircraft measurements have been executed for the purpose of monitoring the long range transported air pollution and estimation of air pollutant in/out-flux over the Yellow sea. Total 74 missions of measurements have been done since 1997, mainly in spring and fall. The main study domain was over $124^{\circ}$E $/sim$ $124^{\circ}$E, $35^{\circ}$N $/sim$ $37^{\circ}$N below 3,000m. In long-term trends, mixing ratios of $SO_{2}$N were around 2 ppbv expect in summer ( < 1 ppbv). NOx exhibited 24 ppbv and have no clear annual trends over the Yellow Sea. The concentrations of 03 were 51, 58, 41 ppbv in spring, summer and fall-winter, respectively. Backward trajectory was performed for three days to investigate the source regions of the air mass. Six regions were divided around Korea peninsular centering at $36^{\circ}$N, $126^{\circ}$E. I, II, III, IV and V regions represents in sequence northeast China and Siberia, Sandong peninsula and Balhae gulf, Sanghi and southern China, the south Pacific included Jeju island and the East sea included Japan. L region correspond to the airmass from Korea peninsula. Influx of $SO_{2}$N was approximately five times higher than outflux in yearly flux variation and showed a decreasing long-term trend since 1998. NOx outflux was average 0.095 ton/km/hr and three times higher than $SO_{2}$ outflux. In/out flux of 03 showed even distribution in yearly basis except 2002 (influx 5.45 ton/km/hr). The transported amounts from I, II, III regions were much higher than those from other region. In seasonal flux variation, influx levels of gas phases were the lowest in summer and the levels gradually increased from fall toward spring. As a result, transport of pollutants begins from fall and prevails in winter and spring.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.753-763
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• 2022

In coastal and inland bays, where most of Korea's aquaculture is located, massive aquaculture damage occurs every year due to frequent anomalous high water temperatures. The interannual fluctuations of water temperature in July over the past four years (2018-2021) were the second largest since 1990 (after the period of 1994-1997) due to anomalous high temperatures, rainy seasons, and typhoons. Through analysis of heat flux and heat balance in areas of concern for high water temperatures (i.e., Cheonsu Bay, Gamak Bay, Guryongpo), the occurrence of high water temperatures in Cheonsu Bay and Gamak Bay in the summer seasons was confirmed to derive mainly from heat inflow through the sea surface from the air. Based on estimations of the average ocean heat transport rate in July for the four-year period of 2018-2021, Cheonsu Bay and Gamak Bay accounted for 13.5% and 62.3% outflow of the net heat flux, respectively. However, the ocean heat transport rate in Guryongpo Hajeong differed significantly from -174.5% to 132.5% of the net heat flux by year depending on the occurrence of cold water mass.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E1
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• pp.23-35
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• 2005

Size distribution of particulate water-soluble ion components was measured at Gosan, Korea using a micro-orifice uniform deposit impactor (MOUDI). Sulfate, ammonium, and nitrate showed peaks in three size ranges; Sulfate and ammonium were of dominant species measured in the fine mode ($D_{p} < 1.8 {\mu}m$). One peak was observed in the condensation mode ($0.218\sim0.532{\mu}m$), and the other peak was obtained in the droplet mode ($0.532\sim1.8{\mu}m$). Considering the fact that the equivalent ratios of ammonium to sulfate ranged from 0.5 to 1.0 in these size ranges, it is inferred that they formed sufficiently neutralized compounds such as ($NH_{4})_{2}SO_{4} and (NH_{4})_{3}H(SO_{4})_{2}$ during the long-range transport of anthropogenic pollutants. On the other hand, nitrate was distributed mainly in the coarse mode ($3.1\sim6.2{\mu}m$) combined with soil and sea salt. Two sets of MOUDI samples were collected in each season. One sample was collected when the concentrations of criteria air pollutants were relatively high, but the other represented relatively clean air quality. The concentrations of sulfate and ammonium particles in droplet mode were the highest in winter and the lowest in summer. When the air quality was bad, the increase of nitrate was observed in the condensation mode ($0.218\sim0.282{\mu}m$). It thus suggests that the nitrate particles were produced through gas phase reaction of nitric acid with ammonia. Chloride depletion was remarkably high in summer due to the high temperature and relative humidity.