• 한국환경과학회지
• /
• 제22권2호
• /
• pp.139-149
• /
• 2013

Anthropogenic increases in greenhouse gas concentrations, primarily through radiative forcing from carbon dioxide, continue to challenge earth's climate. This study quantified $CO_2$ storage and uptake by dominant forest types and age classes in the middle region of Korea. In addition, the role of forest landscapes in reducing atmospheric $CO_2$ against $CO_2$ emissions based on energy consumption was evaluated. Mean $CO_2$ storage and uptake per unit area by woody plants for three forest types and four age classes were estimated applying regression equations derived to quantify $CO_2$ storage and uptake per tree; and computations per soil unit area were also performed. Total $CO_2$ storage and uptake by forest landscapes were estimated by extrapolating $CO_2$ storage and uptake per unit area. Results indicated mean $CO_2$ storage per unit area by woody plants and soils was higher in older age classes for the same forest types, and higher in broadleaved than coniferous forests for the same age classes, with the exception of age class II (11-20 years). $CO_2$ storage by broadleaved forests of age class V (41-50 years) averaged 662.0 t/ha (US$331.0 hundred/ha), highest for all forest types and age classes evaluated. Overall, an increased mean $CO_2$ uptake per unit area by woody plants was evident for older age classes for the same forest types. However, decreased $CO_2$ uptake by broadleaved forests at age class V was observed, compared to classes III and IV with an average of 27.9 t/ha/yr (US$14.0 hundred/ha/yr). Total $CO_2$ storage by woody plants and soils in the study area was equivalent to 3.4 times the annual $CO_2$ emissions, and woody plants annually offset the $CO_2$ emissions by 17.7%. The important roles of plants and soils were associated with 39.1% of total forest area in South Korea, and $CO_2$ emissions comprised 62.2% of the total population. Therefore, development of forest lands may change $CO_2$ sinks into sources. Forest landscape management strategies were explored to maintain or improve forest roles in reducing atmospheric $CO_2$ levels.

• 한국해양환경ㆍ에너지학회지
• /
• 제15권4호
• /
• pp.302-313
• /
• 2012

마산만과 진해만 해저에서 각각 31개와 65개 표층퇴적물을 채취하여 중금속(Al, Fe, Mn, Cr, Cu, Ni, Zn, Pb, As, Cd)을 분석하였다. 중금속 함량은 우리나라 주변의 만 및 하구 퇴적물에 비해 마산만에서 Fe, Cr, Cu, Zn, Pb, Cd, As 등이 높았고 진해만에서 Mn이 높았다. Cu, Zn, Pb, Cd, As는 항구 및 산업시설이 위치한 마산만 해안에서 매우 뚜렷한 증가를 보였으며 공간분포를 통한 오염물질의 근원지 추정이 가능하였다. 오염에 의한 중금속 농축은 지각의 함량을 배경농도로 한 농축비에 근거할 때 진해만은 국지적으로, 반면에 마산만은 넓은 지역에 걸쳐 활발히 진행된 것으로 확인되었으며 특히 Cu, Zn, Pb 및 Cd의 농축비가 대비되었다. As, Cd, Cr, Cu, Pb, Ni, Zn 함량을 중금속 환경기준에 적용한 결과 진해만 시료의 일부와 마산만 시료의 거의 대부분이 주의기준(NOAA ERL, EC TEL, ANZECC ISQG-low, Hong Kong ISQV-low)을 초과하였으며, Cu 및 Zn 함량은 일부 마산만 시료에서 관리기준(NOAA ERM, EC PEL, ANZECC ISQG-high, Hong Kong ISQV-high)을 초과하였다. $I_{geo}$ 값에 근거한 마산만의 중금속 오염은 Fe, Mn, Cr, Ni는 우려할 만한 수준이 아닌 반면 Cu, Zn, Pb는 강한 오염단계에 직면해 있거나 진입해 있으며, Cd는 시료의 87.1%가 강한 오염단계 이상의 심화된 오염상태로 파악되었다.

• 한국작물학회지
• /
• 제59권4호
• /
• pp.532-538
• /
• 2014

비소 함유 골재를 토양개량제로 사용하였을 경우 광미에 포함된 유효태 또는 광물로 존재하는 비소가 용출되어 식물생육에 미치는 영향을 조사하기 위해 실험 한 결과를 요약하면 다음과 같다. 1. 중세사에서 자갈크기의 유비철석 입자시료에서는 비소가 약 $95.28mg\;kg^{-1}$ 정도 함유된 있으나 밭토양 시료에서는 비소가 없는 것으로 조사되었다. 2. 상추 재배토양에 함유된 양을 기준으로 생물학적 이용가능 비소와 그리고 상추로 전이된 비소의 양의 비율을 비교한 결과 토양으로부터 생물학적 이용 가능 비소 형태로 전환된 비소의 비율은 최저 2.20%에서 최대 3.31%로 조사되었다. 3. 상대적 생물학적 이용가능 비소와 상추내 비소 지수는 정의 상관관계를 보이고 있는 반면 이의 비소 지수가 증가함에 따라 상추의 엽장, 엽폭, 엽수, 생체중과 건물중 모두 반비례로 감소하는 것으로 조사되었다. 4. 입자직경이 토양보다 큰 모래 또는 자갈크기의 비소를 포함한 자갈이 혼합량이 증가됨에 따라 식물가용수분 함량이 감소될 뿐만 아니라 상추가 자라는 동안 비소를 포함된 유비철석입자부터 비소가 토양내로 용존되어 작물체내로 전이기 증가되어 상추 엽장, 엽폭 엽수, 생체중, 그리고 건물중에 영향을 준 것으로 판단한다.

• 농업과학연구
• /
• 제44권4호
• /
• pp.463-476
• /
• 2017

Climate change is considered as the greatest threat to our future and descendants. The Korean government has set a target for 2030 to reduce emission of greenhouse gases (GHGs) by 37% from the business-as-usual levels which are projected to reach 851 million metric tons of $CO_2eq$ (Carbon dioxide equivalent). In Korea, GHGs emission from agriculture account for almost 3.1% of the total of anthropogenic GHGs. The GHGs emitted from agricultural land are largely classified into three types: carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$). In Korea, rice paddies are one of the largest agricultural $CH_4$ sources. In order to analyze domestic research trends related to $CH_4$ emission from rice paddies, 93 academic publications including peer reviewed journals, books, working papers, reports, etc., published from 1995 to September 2017, were critically reviewed. The results were classified according to the research purposes. $CH_4$ characteristics and assessment were found to account for approximately 65.9% of the research trends, development of $CH_4$ emission factors for 9.5%, $CH_4$ emission reduction technology for 14.8%, and $CH_4$ emission modeling for 6.3%, etc. A number of research related to $CH_4$ emission characteristics and assessment have been studied in recent years, whereas further study on $CH_4$ emission factors are required to determine an accurate country-specific GHG emission from rice paddies. Future research should be directed toward both studies for reducing the release of $CH_4$ from rice paddies to the atmosphere and the understanding of the major controlling factors affecting $CH_4$ emission.

• 한국대기환경학회지
• /
• 제21권5호
• /
• pp.495-505
• /
• 2005

This study is to estimate source contribution by air pollutantion types (point, area, line) over Seoul metropolitan area. The Air Pollution Model (TAPM) and the highly resolved anthropogenic and biogenic gridded emissions ($1km{\times}1km$) were applied to simulate $SO_2,\;NO_2,\;O_3\;and\;PM_{10}$ concentrations by seasons and contribution was estimated by their source types (point, area, line). The results showed that the simulated concentrations of secondary pollutant agreed well with observed values with an index of agreement (IOA) over 0.4, whereas IOAs over 0.3 were observed for most primary pollutants. The contributions of each source types by seasons were similar. The point source contribution was the highest for $SO_2$ at medium level ranged from $55.1\%\;to\;61.5\%$. But the contribution from area source during for the spring and summer increased as the concentration level increased. The line source contribution was the highest for $NO_2$ at all levels ranged from $68.3\%\;to\;93.1\%$. The results indicate that $SO_2$ emissions should be mainly controlled from point source, as well as area source at higher level concentration. Also, $NO_2\;and\;PM_{10}$ to from line source should be controlled.

• 한국환경과학회지
• /
• 제16권2호
• /
• pp.179-185
• /
• 2007

Nitrous oxide ($N_2O$) is an important trace gas in the atmosphere not only because of its large global warming potential (GWP) but also because of the role in the ozone depletion in the stratosphere. It has been known that soil is the largest natural source of $N_2O$ in global emission. However, anthropogenic sources contributing from industrial section is likely to increase with rising the energy consumption, and transportation as well. In this study, a total of 32 gasoline-powered passenger vehicles (ranging from small to large engine's displacement and also ranging from aged catalyst to new catalyst) were tested on the chassis dynamometer system in order to elucidate the characteristics of $N_2O$ emission from automobiles under different driving modes. Ten different driving modes developed by NIER were adapted for the test. The results show that the $N_2O$ emission decreases logarithmically with increase of vehicle speed over the all test vehicles ($N_2O$) emission = -0.062 Ln (vehicle speed) + $0.289,\;r^2=0.97$). It revealed that the larger engine's displacement, the more $N_2O$ emission were recorded. The correlation between $N_2O$ emission and catalyst aging was examined. It found that the vehicles with aged catalyst (odometer record more than 8,0000km) emit more $N_2O$ than those with new catalyst. Average $N_2O$ emission was $0.086{\pm}0.095\;N_2O-g/km$ (number of samples=210) for the all test vehicles over the test driving modes.

• 한국대기환경학회지
• /
• 제19권2호
• /
• pp.145-156
• /
• 2003

The atmospheric aerosols collected at the 1100 site located in Mt. Halla have been analyzed to investigate their compositions and chemical characteristics . The average concentrations of water-soluble cations were in the order of N $H_{4}$$^{+}$ > $Ca^{2+}$ > N $a^{+}$ > $K^{+}$ > $Mg^{2+}$ during the spring, showing high increase of $Ca^{2+}$ concentration with the value of 0.60 $\mu\textrm{g}$/ $m^3$, and N $H_{4}$$^{+}$> N $a^{+}$> $K^{+}$> $Ca^{2+}$ > $Mg^{2+}$ during the other seasons. The average concentrations of anions have shown in the order of S $O_{4}$$^{2-}$ > N $O_{3}$$^{[-10]}$ >C $l^{[-10]}$ for all seasons, and S $O_{4}$$^{2-}$ and N $O_{3}$$^{[-10]}$ had higher concentrations in spring with the values of 4.84 $\mu\textrm{g}$/ $m^3$ and 1.08 $\mu\textrm{g}$/ $m^3$, respectively. From the analytical data of size-segregated particles by cascade impactor sampling, the components of N $H_{4}$$^{+}$, S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and $K^{+}$ were distributed mainly in fine particles, but $Ca^{2+}$, N $a^{+}$, $Mg^{2+}$ and C $l^{[-10]}$ were included mostly in coarse particles. The correlation coefficients of nss-S $O_{4}$$^{2-}$/N $H_{4}$$^{+}$, nss-S $O_{4}$$^{2-}$/ $K^{+}$ and N $O_{3}$$^{[-10]}$ /nss-C $a^{2+}$ showed quite high values with 0.871, 0.857 and 0.654, respectively Based on the study of enrichment factors, it is considered that N $a^{+}$, $Mg^{2+}$, C $l^{[-10]}$ and $Ca^{2+}$ components were delivered from oceanic and soil sources, but S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and N $H_{4}$$^{+}$ might have other source origins. The factor analysis study showed the aerosol at the 1100 site was influenced mainly by anthropogenic factors, followed by oceanic and soil factors. followed by oceanic and soil factors.

• 한국해양환경ㆍ에너지학회지
• /
• 제10권2호
• /
• pp.118-124
• /
• 2007

해양은 인류가 산업활동을 통하여 방출한 이산화탄소를 대부분 흡수할 수 있으나 자연상태에서는 대기 중 이산화탄소가 해양으로 흡수되는 속도가 매우 느리기 때문에, 가시적인 대기중 온실가스농도저감을 위해서는 인공적으로 해양의 중심층으로 이산화탄소를 직접 분사시켜 해수에 용해시키는 방법을 사용할 수 있다. 화력발전소나 제철소 등 이산화탄소를 대량으로 발생시키는 곳에서 이를 직접 포집하여 선박으로 필리핀해나 일본 동쪽의 공해역으로 운송하여 중심층(수심 $2,000{\sim}3,000\;m$)에 분사시킨다면 수 백년 이상 해양에 저장할 수 있다. 해수에 용해된 이산화탄소는 분사지역을 중심으로 해수의 pH를 감소시키는데, 환경변화가 매우 적은 심해에 적응한 생물들은 작은 환경의 변화에도 큰 영향을 받을 수 있기 때문에, $CO_2$ 분사를 시행하려면 이에 의한 생태영향평가를 수행해야 한다. 생태계에 나타나는 손실이 $CO_2$ 분사에 의한 이득보다 작을 경우에만 심층 분사를 통한 해양 이산화탄소 격리가 경제적인 측면에서 유효하다.

• 대기
• /
• 제23권1호
• /
• pp.93-102
• /
• 2013

Atmospheric transport pathway of an air mass is an important constraint controlling the chemical properties of the air mass observed at a designated location. Such information could be utilized for understanding observed temporal variabilities in atmospheric concentrations of long-lived chemical compounds, of which sinks and/or sources are related particularly with natural and/or anthropogenic processes in the surface, and as well as for performing inversions to constrain the fluxes of such compounds. The Lagrangian particle dispersion model FLEXPART provides a useful tool for estimating detailed particle dispersion during atmospheric transport, a significant improvement over traditional "single-line" trajectory models that have been widely used. However, those without a modeling background seeking to create simple back-trajectory maps may find it challenging to optimize FLEXPART for their needs. In this study, we explain how to set up, operate, and optimize FLEXPART for back-trajectory analysis, and also provide automatization programs based on the open-source R language. Discussions include setting up an "AVAILABLE" file (directory of input meteorological fields stored on the computer), creating C-shell scripts for initiating FLEXPART runs and storing the output in directories designated by date, as wells as processing the FLEXPART output to create figures for a back-trajectory "footprint" (potential emission sensitivity within the boundary layer). Step by step instructions are explained for an example case of calculating back trajectories derived for Anmyeon-do, Korea for January 2011. One application is also demonstrated in interpreting observed variabilities in atmospheric $CO_2$ concentration at Anmyeon-do during this period. Back-trajectory modeling information introduced in this study should facilitate the creation and automation of most common back-trajectory calculation needs in atmospheric research.

• 방사성폐기물학회지
• /
• 제12권4호
• /
• pp.275-286
• /
• 2014

본 연구에서는 결정질 기반암에 위치하는 12개 시추공의 지하수 수질을 분석하여, 다변량 통계 분석법을 활용하여 지하수 수질 진화 특성 및 성분 기원을 평가하였다. 지하수 수질 유형은 Na(Ca)-$HCO_3$형과 Ca-$HCO_3$형이 가장 우세하여, 물-암석 반응에 의한 직접적인 양이온 교환 반응($Ca^{2+}{\rightarrow}Na^+$)을 지시하며, 현장 지하수 특성과 실내 지하수 분석 결과에 기초한 연구지역의 지하수 수질 진화는 초기 내지 중간 정도의 단계를 지시하는 것으로 사료된다. 다변량 분석 결과, 인위적인 기원인 $NO_3{^-}$와 다른 성분들 간의 상관성을 살펴보면, $Na^+$, $Cl^-$와 양의 상관성을 나타난다. 염무의 기원인 $Cl^-$와는 $Na^+$, $SO{_4}^{2-}$, $Mg^{2+}$, $K^+$와 양의 상관성을 나타낸다. 그러나 다른 성분들($Ca^{2+}$, $Fe^{2+}$, $HCO_3{^-}$, $F^-$, $SiO_2$)과는 상관성이 나타나지 않는다. $Cl^-$ 농도가 일반적인 지하수 수질 범위에 포함되고 $NO_3{^-}$ 농도는 먹는물 수질기준치 이하로서 농도가 매우 낮으며, 대부분의 광물에 대해서 지하수 화학성분들은 불포화상태를 지시한다. 따라서, 연구지역의 수질 성분들은 대부분 물-암석 반응을 통한 자연적인 기원을 지시하고 부분적으로는 자연적인 염무와 농업과 관련된 인위적인 오염으로부터 기인된다.