• Journal of the Optical Society of Korea
• /
• 제14권3호
• /
• pp.204-208
• /
• 2010

A scanning imaging spectrograph system was used in this study to retrieve readings of the 2-D distribution of $SO_2$ and BrO around the crater of the Sakurajima volcano in Japan. The measurement was carried out during the daytime on November 2, 2005. Measurements were made at the surface of the site, located 5 km from the Sakurajima crater. One hundred horizontal scans were performed. Each column scanned by the system consists of 64 vertical pixels in order to retrieve the spatial distributions of BrO and $SO_2$ in the plume in terms of slant column densities (SCDs). Measured spectra were analyzed to identify and quantify $SO_2$ and BrO in the volcanic plume utilizing the plume's specific absorption features in the ultra violet region. Two-dimensional BrO and $SO_2$ distributions in SCD were retrieved horizontally covering the upwind, crater and downwind areas, and vertically, including the plume in the center of the scanned image. Both horizontal and vertical dispersions of $SO_2$ SCD from the crater were successfully measured to be from $10^{17}$ to $4.5{\times}10^{18}$ molecules $cm^{-2}$. However, BrO was measured below $10^{15}$ molecules $cm^{-2}$, which is considered its background level.

• Journal of Radiation Protection and Research
• /
• 제20권2호
• /
• pp.79-83
• /
• 1995

과거 물분자와 전리방사선과의 상호작용에 의하여 생성된 방사능 극소입자에 관한 많은 연구결과가 보고되어 왔다. 특히 최근연구에서는 물분자의 방사성분해 에 의해 발생한 높은 농도의 수산화래디칼은 실내의 유기가스와 반응 후 저증기압의 화합물로 변하여 극소입자를 형성한다고 알려져왔다. 본 연구에서는 라돈의 첫째딸핵종인 Po-218에 대한 대기가스와 물분자와의 상호의존성을 조사할 목적으로, 실내가스의 최적제어가 가능한 라돈챔버를 사용하여 일련의 실험을 수행하였다. 제작된 정전기분광계를 사용하여 라돈의 첫째딸핵종인 Po-218이온에 대해 $0.07-5.0cm^2/V\;sec$ 범위의 이동도스펙트럼을 측정하였으며, 대기가스로 0.5ppm에서 5ppm까지의 $SO_2$가스를 사용하여 실험결과를 분석하였다. 라돈챔버내에 물분자의 첨가와 동 물분자의 방사성분해에 의하여 생성된 수산화래디칼에 의한 극소입자들의 형성과정을 확인하였으며 $PoO_x^+$ 이온 주변에 $SO_2$가스가 부착하면서 일어나는 화학반응에 대한 화학적 동특성연구를 수행하였다.

• 한국대기환경학회지
• /
• 제13권6호
• /
• pp.427-437
• /
• 1997

Complex terrain which is rather typical topographic character in Korea would greatly influence the dispersion of air pollutant. In this study, we investigated how the complex terrain in the vicinity of the coal-fired plant affects the air dispersion modeling results by using several US EPA models: SCREEN, CTSCREEN, ISCLT3, ISCST3, and RTDM. Screening analysis was followed by long-term analysis, and the plume movement over the terrain was precisely tracked for selected cases. Screening analysis revealed that the highest concentration of sulfur dioxide occurs at the downwind distance of 1.3 km under the unstable conditions with weak winds. However, this highest level of $SO_2$ could be raised by 4 times even in the presence of a hill of 170 m at a distance of 2 to 3 km. Seasonal and annual average concentrations predicted with the ISCLT3, ISCST3, and RTDM models showed a rapid incrase of $SO_2$ levels in front of the high mountains which are located more than 15 km away fromt the source. The highest concentrations predicted with ISCST3 were significantly higher than those with ISCLT3 and RTDM mainly because ISCST3 chooses simple-terrain model calculations for receptors between stack height and plume height. Although the highest levels under the stable conditions were usually found in the areas beyond 15 km or more, their absolute values were not so high due to enough dispersion effects between the source and the receptors.

• 한국대기환경학회지
• /
• 제10권4호
• /
• pp.252-259
• /
• 1994

A ground station has been established at Kosan, Cheju Island, since January of 1992 for the monitoring of background air Pollutant levels in Korea. Anthropogenic pollutant sources and meteorological conditions of Kosan were surveyed. Concentrations of SO$_2$, NO, NO$_{y}$ and $O_3$, were measured and analyzed for the period of February through December, 1992. The annual means of NO and SO$_2$, levels were very low in comparison to other urban's levels and similiar to other country's background levels. The annual mean of $O_3$, level was higher than urban's but comparable to other coastal region's. The NO concentration showed a distinct seasonal and diurnal variations. Summer peak was detected in the monthly means of NO and smooth peak around noon was found in the annual means of hourly data. Diurnal variation of the SO$_2$ concentration was barely detected but a slice increase in winter was detected. The $O_3$, concentration data, however, showed seasonal and diurnal variations similar to the urban's.an's.

• 한국대기환경학회지
• /
• 제32권4호
• /
• pp.435-447
• /
• 2016

Anthropogenic emissions of $PM_{2.5}$ in Chuncheon are considered to be low according to the national emissions inventory; however, the atmospheric $PM_{2.5}$ concentrations have been reported to be higher than or at least similar to those measured in metropolitan (e.g. Seoul) and/or in industrial cities (e.g. Incheon, Ulsan). In this study, the concentrations of $PM_{2.5}$ and its ionic and carbonaceous compounds were measured from Jan. 2013 to Dec. 2014 in Chuncheon, Korea to identify the characteristics of high $PM_{2.5}$ concentration event. Average $PM_{2.5}$ concentration was $34.6{\mu}g/m^3$, exceeding the annual air quality standard ($25{\mu}g/m^3$). The most abundant compound was organic carbon (OC), comprising 26% of $PM_{2.5}$ mass, followed by $SO_4{^{2-}}$. Among 14 high concentration events, three events showed clearly enhanced contributions of OC, $SO_4{^{2-}}$, $NO_3{^-}$ and $NH_4{^+}$ to $PM_{2.5}$ under the fog events. One event observed in summer showed high concentration of $SO_4{^{2-}}$ while the high wind speeds and the low $PM_{2.5}/PM_{10}$ ratios were observed for the two high concentration events. These results indicate that the secondary aerosol formation under the fog events and high atmospheric temperature as well as the regional and/or the long-range transport were important on enhancing $PM_{2.5}$ concentration in Chuncheon. Cluster analysis based on back trajectories also suggested the significant impacts of regional transport from China and metropolitan areas of Korea on $PM_{2.5}$ in Chuncheon.

• 한국산학기술학회논문지
• /
• 제9권5호
• /
• pp.1349-1353
• /
• 2008

충청남도, 천안시 대기 에어로졸의 입경별 농도 및 이온성분 특성을 분석하고자, 2006년 3월부터 2007년 4월까지 천안시 상명대학교에서 Cascade Impactor를 장착한 High Volume Air Sampler를 이용하여 대기 시료를 채취 분석하였다. 입경별 에어로졸의 일평균농도는 TSP, PM10, PM2.5, PM1이 각각 61.7, 55.2, 43.7, $33.2{\mu}g/m^3$였으며, 직경이 $1{\sim}3{\mu}m$인 영역을 경계로 조대영역과 미세영역으로 나누어지는 전형적인 도심지 특성을 나타냈다. 이 중 미세영역입자인 PM2.5이 전체 에어로졸의 70.8%를 차지하였다. 이들 에어로졸 입자의 성분 분석 결과 양이온은 ${NH_{4}}^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$이, 음이온은 ${SO_{4}}^{2-}$, ${NO_{3}}^-$, $Cl^-$가 주요 성분이었으며, 이들 수용성 이온이 차지하는 비율은 조대입자에서 37.4%, 미세입자에서 46.2%였다.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2006년도 춘계학술대회 논문집
• /
• pp.57-58
• /
• 2006

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2000년도 춘계학술대회 논문집
• /
• pp.125-126
• /
• 2000

현재 공단지역에서 발생하는 오염물질을 파악하기 위해서는 오염물질이 배출되는 곳에 TMS를 설치하거나 측정하고자 하는 지점에 습식법을 이용하여 오염물질을 측정하는 방법이 사용되고 있다. 하지만 이러한 TMS나 습식법을 이용하여 오염물질을 측정하기 위해서는 고가의 설치비나 인력 장비 문제로 인하여 동시에 여러 지역을 측정하기 어렵다는 단점을 가지고 있으며, 특히 공단 지역과 같은 특수한 지역의 오염물질의 경향을 파악하기 위해서는 더욱 그러하다. (중략)

• Asian Journal of Atmospheric Environment
• /
• 제12권2호
• /
• pp.109-126
• /
• 2018

This paper presents seasonal variation of $PM_{10}$ over five urban sites in Sabah, Malaysia for the period of January through December 2012. The variability of $PM_{10}$ along with the diurnal and weekly cycles of CO, $NO_2$, $SO_2$, and $O_3$ at Kota Kinabalu site were also discussed to investigate the possible sources for increased $PM_{10}$ concentration at the site. This work is crucial to understand the behaviour and possible sources of $PM_{10}$ in the urban atmosphere of Sabah region. In Malaysia, many air pollution studies in the past focused in west Peninsular, but very few local studies were dedicated for Sabah region. This work aims to fill the gap by presenting the descriptive statistics on the variability of $PM_{10}$ concentration in the urban atmosphere of Sabah. To further examine its diurnal and weekly cycle pattern, its responses towards the variations of CO, $NO_2$, $SO_2$, and ozone were also investigated. The highest mean value of $PM_{10}$ for the whole study period is seen from Tawau ($35.7{\pm}17.8{\mu}g\;m^{-3}$), while the lowest is from Keningau ($31.9{\pm}18.6{\mu}g\;m^{-3}$). The concentrations of $PM_{10}$ in all cities exhibited seasonal variations with the peak values occurred during the south-west monsoons. The $PM_{10}$ data consistently exhibited strong correlations with traffic related gaseous pollutants ($NO_2$, and CO), except for $SO_2$ and $O_3$. The analysis of diurnal cycles of $PM_{10}$ levels indicated that two peaks were associated during the morning and evening rush hours. The bimodal distribution of $PM_{10}$, CO, and $NO_2$ in the front and at the back of ozone peak is a representation of urban air pollution pattern. In the weekly cycle, higher $PM_{10}$, CO, and $NO_2$ concentrations were observed during the weekday when compared to weekend. The characteristics of $NO_2$ concentration rationed to CO and $SO_2$ suggests that mobile sources is the dominant factor for the air pollution in Kota Kinabalu; particularly during weekdays.

• 천문학회보
• /
• 제42권2호
• /
• pp.62.3-63
• /
• 2017

The Mars Atmosphere and Volatile (MAVEN) mission has been providing valuable information on the atmospheric loss of Mars since its launch in November 2013. The Neutral Gass and Ion Mass Spectrometer (NGIMS) onboard MAVEN, was developed to analyze the composition of the Martian upper atmospheric neutrals and ions depending on various space weather conditions. We investigate a variation of upper atmospheric ion densities depending on the interplanetary coronal mass ejections (ICMEs). It is known that the Mars has a very weak global magnetic field, so upper atmosphere of Mars has been strongly affected by the solar activities. Meanwhile, a strong crustal magnetic field exists on local surfaces, so they also have a compensating effect on the upper atmospheric loss outside the Mars. The weak crustal field has an influence up to 200km altitude, but on a strong field region, especially east longitude of $180^{\circ}$ and latitude of $-50^{\circ}$, they have an influence over 1,400km altitude. In this paper, we investigated which is more dominant between the crustal field effect and the ICME effect to the atmospheric loss. At 400km altitude, the ion density over the strong crustal field region did not show a significant variation despite of ICME event. However, over the other areas, the variation associated with ICME event is far more overwhelming.