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손장호,김기현 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.5
This study examines the local oxidation chemistry of reduced sulfur compounds (RSC) in the urban air. The chemical conversion of RSC (such as DMS, CS₂, H₂S, DMDS, and CH₃SH) to SO₂ was modeled using a photochemical box model. For our model prediction of the RSC oxidation, measurements were carried out from an urban monitoring station in Seoul (37.6˚N, 127.0˚E), Korea for three separate time periods (Sep. 17~18; Oct 23; and Oct. 27~28, 2003). The results of our measurements indicated that DMS and H₂S were the dominant RSC with their concentrations of 370±140 and 110±60 pptv, respectively. The conversion of DMDS to SO₂ can occur efficiently in comparison to other RSC, but it is not abundant enough to affect their cycles. The overall results of our study indicate that the photochemical conversion of the RSC can contribute < 20% of the observed SO₂.
연속측정방법을 이용한 도심권 대기질 내 저농도 황화합물의 관측에 대한 연구
최여진,김기현,오상인,손장호 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.2
In this study, the concentrations of major reduced sulfur compounds (H₂S, CH₃SH, DMS, and DMDS) were determined from ambient air in a monitoring station located in the mid-eastern area of Seoul. Measurements of sulfur species were conducted by the combination of on-line air sampling, thermal desorption, and capillary GC/PFPD analysis. A total number of 143 hourly samples were collected in the two time periods set between June and July 2003. The mean concentrations of four sulfur species measured in the whole study period were found on the order: DMS (535±183H) > H₂S (47±10) > DMDS (35±22) > CH₃SH (6.19±29.4 pptv). The results of this study show that the concentrations of DMS at the study area are generally higher than those reported previously in the oceanic environments, while those of other sulfur species are not easy to compare with due to the lack of data. The H₂S concentrations were generally higher during the daytime than the nighttime, whereas those of others generally exhibited a reversed diurnal pattern. The overall results of our study suggest that the distribution of major reduced S compounds should be controlled by diverse processes in the urban area.
Shon, Zang-Ho Korean Society for Atmospheric Environment 2002 한국대기환경학회지 Vol.18 No.E2
Dimethyl sulfide (DMS) is the major sulfur gas released from the ocean. The atmospheric DMS released from the ocean is oxidized mainly by hydroxyl (OH) radical during the day and nitrate (NO$_3$) radical at night to form sulfur dioxide (SO$_2$) as well as other stable products. The oxidation mechanism of DMS via OH has been known to proceed by two channels; abstraction and addition channels. The major intermediate product of the addition channel has been known to be dimethylsulfoxide (DMSO) based on laboratory chamber studies and field experiments. However, a branching ratio for DMSO formation is still uncertain. The reaction of DMSO with OH ultimately produces SO$_2$and dimethylsulfone. The major product of the abstraction channel has known to be SO$_2$from laboratory chamber studies. But overall conversion efficiency for DMS to SO$_2$from DMS oxidation is still inconsistent in the literature. Based on laboratory and field studies, the conversion efficiency from the abstraction channel is likely to be greater than 0.5, while that from the addition channel is likely to be greater than 0.6. Overall conversion efficiency from DMS to SO$_2$might be greater than 0.5 based on the above two values in the remote marine boundary layer (MBL). This high efficiency in the remote MBL is supported by strong coupling between DMS and SO$_2$measurements with high temporal resolution.
Evaluation of Methyl lodide ($CH_3I$) Flux Based on Airborne field Observations
Shon, Zang-Ho Korean Society for Atmospheric Environment 2004 한국대기환경학회지 Vol.20 No.E2
A total of 10 boundary layer sampling events over the Pacific Ocean were analyzed for the purpose of defining the sea-to-air $CH_3$I flux using a mass balance photochemical model. These events were recorded on the National Center for Atmospheric Research (NCAR) C-130 aircraft as part of the Aerosol Charac-terization Experiment (ACE 1). The latitude range, covered by these events, was 2$^{\circ}$ N to 55$^{\circ}$ S. The flux ranges were 4 to 33 nmol m$^{-2}$ day$^{-1}$ , with an average value of 11$\pm$8 nmol m$^{-2}$ day$^{-1}$ . This study also indicated that the current approach to estimate the flux was not systematically different from the sea-air exchange model.
Photochemistry of reduced sulfur compounds in a landfill environment
Shon, Zang-Ho,Kim, Ki-Hyun,Jeon, Eui-Chan,Kim, Min-Young,Kim, Yoo-Keun,Song, Sang-Keun Elsevier 2005 Atmospheric environment Vol.39 No.26
<P><B>Abstract</B></P><P>This study examines the distribution characteristics of reduced sulfur compounds (RSCs such as DMS, CS<SUB>2</SUB>, H<SUB>2</SUB>S, DMDS, and CH<SUB>3</SUB>SH) and their photochemical reactions in landfill air. The photochemical conversions of RSCs to a further oxidized form, SO<SUB>2</SUB> were evaluated in the landfill site using a photochemical box model. Measurements of RSCs were carried out from landfill areas in Daegu, Korea, during a wintertime period (e.g., 13–16 Jan 2004). This study indicated that H<SUB>2</SUB>S was the most dominant RSC in the landfill, with the concentrations of 4.2±5.8ppbv. The chemical species of RSCs, which may exert influences on the SO<SUB>2</SUB> production depending on sampling conditions, were found to include DMS, DMDS, and H<SUB>2</SUB>S. In general, the RSC contribution to the observed SO<SUB>2</SUB> levels was insignificant in the sampling sites investigated. Overall, the extent of the RSC oxidation to the observed SO<SUB>2</SUB> varied dramatically during the sampling period. The photochemical conversion of the RSCs in the landfill environment can account for about 15% of the observed SO<SUB>2</SUB>, on average. There was a strong correlation between DMS and SO<SUB>2</SUB> concentration levels during the study period.</P>
Evaluation of Methyl lodide(CH₃I) Flux Based on Airborne Field Observations
Zang-Ho Shon 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.E2
A total of 10 boundary layer sampling events over the Pacific Ocean were analyzed for the purpose of defining the sea-to-air CH₃I flux using a mass balance photochemical model. These events were recorded on the National Center for Atmospheric Research (NCAR) C -130 aircraft as part of the Aerosol Charac-terization Experiment (ACE 1). The latitude range, covered by these events, was 2˚N to 55˚S. The flux ranges were 4 to 33 nmol m^-2 day^-1, with an average value of 11±8 nmol m^-2 day^-1. This study also indicated that the current approach to estimate the flux was not systematically different from the sea-air exchange model.
Characteristics of Atmospheric Metalliferous Particles during Large-Scale Fireworks in Korea
Shon, Zang-Ho,Jeong, Ju-Hee,Kim, Yoo-Keun Hindawi Limited 2015 Advances in meteorology Vol.2015 No.-
<P>The effect of large-scale firework events on urban background trace metal concentrations was investigated using 24 hr data collected over 3 days at three sites in Busan Metropolitan City, Republic of Korea, during the falls (Oct.) of 2011–2013. The firework events increased local background concentrations of trace metals as follows: K (1.72 times), Sr (2.64 times), As (2.86 times), Pb (2.91 times), and Al (5.44 times). The levels of some metals did not always drop to background level one day after the firework event. The contribution of fireworks to trace metal concentration levels (and emissions) for 2011 event was negligible compared to 2012 and 2013 events due to different meteorological conditions (precipitation). In addition, the impact of firework events on the ambient concentration levels of trace metals was likely to be different depending on their chemical speciation. The impact of firework events in Busan on urban air quality (trace metal) was less intense compared to other similar festivals worldwide. The largest emission of trace metals and elements from firework burning was represented by K (128–164 kg), followed by Pb, Cd, Cu, Mg, Ba, As, Al, Ga, Co, and Na.</P>