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Jeong, Ukkyo,Kim, Jhoon,Lee, Hanlim,Lee, Yun Gon Elsevier 2017 Atmospheric environment Vol.150 No.-
<P>It is important to estimate the effects of the long-range transport of atmospheric pollutants for efficient and effective strategies to control air quality. In this study, the contributions of trans-boundary transport to the mean concentrations of SO2, NO2, CO, and PK in Seoul, Korea from 2001 to 2014 were estimated based on the conditional potential source contribution function (CPSCF) method. Eastern China was found to be the major source of trans-boundary pollution in Seoul, but moderate sources were also located in northeastern China. The contribution of long-range transport from Japan was negligible. The spatial distributions of the potential source contribution function (PSCF) values of each pollutant showed reasonable consistency with their emission inventory and satellite products. The PSCF values of SO2 and PM10 from eastern China were higher than those of NO2 and CO. The mean concentrations of SO2, NO2, CO, and PM10 in Seoul for the period from 2001 to 2014 were 534, 37.0, and 619.1 ppb, and 57.4 4 mu g/m(3), respectively. The contributions of long-range transport to the mean concentrations of SO2, NO2, CO, and PM10 in Seoul were 0.74, 3.4, and 39.0 ppb, and 12.1 mu g/m(3), respectively, which are 14%, 9%, 6%, and 21% of the mean concentrations, respectively. The annual mean concentrations of SO2 and NO2 followed statistically significant increasing linear trends (0.5 and 1.6 ppb per decade, respectively), whereas the trends in the annual mean concentrations of CO and PM10 were statistically insignificant. The trends in the ratio of the increased concentrations associated with long-range transport to the annual mean concentrations of the pollutants were statistically insignificant. However, the results indicate that the trans-boundary transport of 502, NO2, CO, and Milio from eastern China consistently affected air quality in Seoul over the study period (2001-2014). Regionally, the effects of the long-range transport of pollutants from Beijing and Harbin-Changchun on air quality in Seoul have become more significant over this period. (C) 2016 Elsevier Ltd. All rights reserved.</P>
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Jeong, Ukkyo,Kim, Jhoon,Lee, Hanlim,Jung, Jinsang,Kim, Young J.,Song, Chul H.,Koo, Ja-Ho Royal Society of Chemistry 2011 Journal of environmental monitoring Vol.13 No.7
<P>The contributions of long range transported aerosol in East Asia to carbonaceous aerosol and particulate matter (PM) concentrations in Seoul, Korea were estimated with potential source contribution function (PSCF) calculations. Carbonaceous aerosol (organic carbon (OC) and elemental carbon (EC)), PM<SUB>2.5</SUB>, and PM<SUB>10</SUB> concentrations were measured from April 2007 to March 2008 in Seoul, Korea. The PSCF and concentration weighted trajectory (CWT) receptor models were used to identify the spatial source distributions of OC, EC, PM<SUB>2.5</SUB>, and coarse particles. Heavily industrialized areas in Northeast China such as Harbin and Changchun and East China including the Pearl River Delta region, the Yangtze River Delta region, and the Beijing–Tianjin region were identified as high OC, EC and PM<SUB>2.5</SUB> source areas. The conditional PSCF analysis was introduced so as to distinguish the influence of aerosol transported from heavily polluted source areas on a receptor site from that transported from relatively clean areas. The source contributions estimated using the conditional PSCF analysis account for not only the aerosol concentrations of long range transported aerosols but also the number of transport days effective on the measurement site. Based on the proposed algorithm, the condition of airmass pathways was classified into two types: one condition where airmass passed over the source region (PS) and another condition where airmass did not pass over the source region (NPS). For most of the seasons during the measurement period, 249.5–366.2% higher OC, EC, PM<SUB>2.5</SUB>, and coarse particle concentrations were observed at the measurement site under PS conditions than under NPS conditions. Seasonal variations in the concentrations of OC, EC, PM<SUB>2.5</SUB>, and coarse particles under PS, NPS, and background aerosol conditions were quantified. The contributions of long range transported aerosols on the OC, EC, PM<SUB>2.5</SUB>, and coarse particle concentrations during several Asian dust events were also estimated. We also investigated the performance of the PSCF results obtained from combining highly time resolved measurement data and backward trajectory calculations <I>via</I> comparison with those from data in low resolutions. Reduced tailing effects and the larger coverage over the area of interest were observed in the PSCF results obtained from using the highly time resolved data and trajectories.</P> <P>Graphic Abstract</P><P>The contributions of long range transported aerosol in East Asia to carbonaceous aerosol and particulate matter (PM) concentrations in Seoul, Korea were estimated with potential source contribution function (PSCF) calculations. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0em00659a'> </P>
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VE기법을 이용한 다기능 토석류 유출저감시설의 비용/편익 분석
정욱교(Jung, Ukkyo),지용근(Jee, Yonggeun),이재성(Lee, Jaesung),김병식(Kim, Byungsik) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.4
우리나라는 국지성 집중호우로 인해 토석류 피해가 빈번히 발생하고 있으며 인적·물적 피해저감을 목표로 토석류 유출저감시설을 설치하고 있다. 일반적으로 이와 같은 시설물 설치 시 경제성을 검토하기 위해 비용/편익 분석을 적용하고 있지만 다기능을 가지는 토석류 유출저감시설의 경우는 방재시설로서 편익을 정량화하는데 한계가 있어 일반적인 비용/편익 분석을 적용하기는 어렵다. 따라서 본 연구에서는 토석류 유출저감시설의 기능적 효과를 검토하기 위해 VE기법을 채택하여 분석을 수행하였으며, 이를 위해 MLPM기법을 이용한 다단계 성능평가, 비용절감 효과 분석을 위해 LCC분석을 수행하였다. 그 결과 다기능 토석류 유출저감시설의 성능은 17.6% 향상, 비용은 56,119천원 절감, 가치는 38.81% 향상되는 것으로 나타났다. 다기능 토석류 유출저감시설은 방재시설로써 충분히 가치가 있는 것으로 판단되며, VE기법은 방재시설의 비용대비 가치와 성능평가에 활용가능성이 높을 것으로 판단된다. Personnel and material damage of Debris flow, caused by localized heavy rainfall, has been occurred frequently in Korea, and runoff mitigation facilities of debris flow have been set up for the damage reduction. In general, the benefit/cost analysis is applied to examine the economic feasibility of installing such facilities. However, it is difficult to apply the general benefit/cost analysis because of the limitation in quantifying benefits as a disaster prevention facility in the case of multipurpose debris flow mitigation module (MudM2). Therefore, in this study, VE (Value Engineering) technique was applied to assess the functional effect of the debris flow reduction facility, and for the analysis Multi-Level Performance Measurement (MLPM) and Life Cycle Cost (LCC) analysis was adopted. As the result, the performance index of MudM2 was improved by 17.6%, and the cost was reduced by 56,119 thousand won, value index improved by 38.81%. Therefore, it was concluded that MudM2 is worthy of disaster prevention facilities. The VE technique will be helpful in evaluating the value of disaster prevention facilities.
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Inter-comparison of NO<sub>2</sub> column densities measured by Pandora and OMI over Seoul, Korea
Yun, Seoyeon,Lee, Hanlim,Kim, Jhoon,Jeong, Ukkyo,Park, Sang Seo,Herman, Jay The Korean Society of Remote Sensing 2013 大韓遠隔探査學會誌 Vol.29 No.6
Total Vertical Column Density (VCD) of $NO_2$, a key component in air quality and tropospheric chemistry was measured using a ground-based instrument, Pandora, in Seoul from March 2012 to October 2013. The $NO_2$ measurements using Pandora were compared with those obtained by satellite remote sensing from Ozone Monitoring Instrument (OMI) where the intercomparison characteristics were analyzed as a function of measurement geometry, cloud amount and aerosol loading. The negative biases of the OMI $NO_2$ VCD were larger when cloud amount and Aerosol Optical Depth (AOD) were higher. The correlation coefficient between $NO_2$ VCDs from Pandora and OMI was 0.53 for the entire measurement period, whereas the correlation coefficient between the two was 0.74 when the cloud amount and AOD were low (cloud amount<3, AOD<0.4). The low bias of OMI data was associated with the shielding effect of the cloud and the aerosols.
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Kim, Woogyung,Lee, Hanlim,Kim, Jhoon,Jeong, Ukkyo,Kweon, Jung Elsevier 2012 Atmospheric environment Vol.56 No.-
<P><B>Abstract</B></P><P>In order to investigate seasonal and diurnal variation of primary organic carbon (POC) and secondary organic carbon (SOC) concentrations in a megacity, hourly measurements of particulate and gaseous pollutants were carried out in Seoul from January to December 2010. The EC Tracer Method (ECTM) and the Multiple Regression Method (MRM) have been used to estimate seasonal and diurnal concentrations of POC and SOC concentrations. Annual mean SOC concentrations estimated by ECTM (SOC<SUB>ECTM</SUB>) and MRM (SOC<SUB>MRM</SUB>) accounted for 14.61 and 17.21% of TOC concentrations, respectively. Seasonal patterns in SOC<SUB>MRM</SUB> were comparable to those of SOC<SUB>ECTM</SUB>, but the annual average SOC<SUB>MRM</SUB> was about 15% greater than that of SOC<SUB>ECTM</SUB>. In spring, however, a large discrepancy was observed between SOC<SUB>ECTM</SUB> and SOC<SUB>MRM</SUB>, which is thought to be due to a high ozone concentration and primary TOC/EC ratio. Regarding the annual mean diurnal characteristics, POC concentration showed peaks around 10:00 and 00:00 local time that were also observed in diurnal variations of TOC and EC concentrations. Annual mean SOC concentration, however, showed peaks at around 15:00. In the morning over all seasons, we found discrepancies between SOC<SUB>ECTM</SUB> and SOC<SUB>MRM</SUB> due to overestimated SOC<SUB>ECTM</SUB> concentration. The diurnal variations in SOC concentrations were found to have seasonal characteristics. The diurnal pattern of SOC concentration in spring was similar to that in autumn, and SOC concentrations in all seasons with the exception of winter showed a peak at around 15:00. In summer, however, the SOC concentration peak at around 15:00 was greater by 70%, 81%, and 54% than the peaks seen in spring, autumn, and winter, respectively, which could be explained by the high ozone concentration and strong UV radiation in summer. From 10:00 to 15:00 in summer, the average increase rates in SOC<SUB>ECTM</SUB> and SOC<SUB>MRM</SUB> were 0.39 and 0.24 μg m<SUP>−3</SUP> h<SUP>−1</SUP>, respectively. In winter, negligible diurnal variations of estimated SOC concentrations demonstrate that SOC formation is less active than in other seasons. The high concentration level of mean SOC in winter could be attributed to a low mixing height or stagnant atmospheric condition.</P> <P><B>Highlights</B></P><P>► First estimation of diurnal SOC variations was carried out in a megacity site. ► Enhanced SOC concentration was estimated in summer. ► The diurnal variations in SOC concentrations show seasonal characteristics. ► SOC concentrations were peaked at 3:00 PM for all seasons with different magnitudes. ► The results from EC tracer and multiple regression methods show slight discrepancy.</P>
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