• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.275-290
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• 2021

Sulfur dioxide (SO2) in the atmosphere is mainly generated from anthropogenic emission sources. It forms ultra-fine particulate matter through chemical reaction and has harmful effect on both the environment and human health. In particular, ground-level SO2 concentrations are closely related to human activities. Satellite observations such as TROPOMI (TROPOspheric Monitoring Instrument)-derived column density data can provide spatially continuous monitoring of ground-level SO2 concentrations. This study aims to propose a 2-step residual corrected model to estimate ground-level SO2 concentrations through the synergistic use of satellite data and numerical model output. Random forest machine learning was adopted in the 2-step residual corrected model. The proposed model was evaluated through three cross-validations (i.e., random, spatial and temporal). The results showed that the model produced slopes of 1.14-1.25, R values of 0.55-0.65, and relative root-mean-square-error of 58-63%, which were improved by 10% for slopes and 3% for R and rRMSE when compared to the model without residual correction. The model performance by country was slightly reduced in Japan, often resulting in overestimation, where the sample size was small, and the concentration level was relatively low. The spatial and temporal distributions of SO2 produced by the model agreed with those of the in-situ measurements, especially over Yangtze River Delta in China and Seoul Metropolitan Area in South Korea, which are highly dependent on the characteristics of anthropogenic emission sources. The model proposed in this study can be used for long-term monitoring of ground-level SO2 concentrations on both the spatial and temporal domains.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.179-184
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• 2013

BACKGROUND: Accurate estimates of total direct $CH_4$ emissions from croplands on a country scale are important for global budgets of anthropogenic sources of $CH_4$ emissions and for the development of effective mitigation strategies. Methane production resulted by the anaerobic decomposition of organic compounds where $CO_2$ acts as inorganic electron acceptor. This process could be affected by the addition of rice straw, water management and rice variety itself. METHODS AND RESULTS: Rice (Oryza sativa L. Japonica type, var Samkwangbyeo) was cultivated in four plots: (1) Nitrogen-Phosphorus-Potassium (NPK) ($N-P_2O_5-K_2O$:90-45-57 kg/ha); (2) NPK plus 3 Mg/ha rice straw (RS3); (3) NPK plus 5 Mg/ha rice straw (RS5); (4) NPK plus 7 Mg/ha rice straw (RS7) for 3 years (2010-2012) and the rice straw incorporated in fall (Nov.) in Gyeonggi-do Hwaseong-si. Gas samples were collected using the closed static chamber which were installed in each treated plot of $152.9m^2$. According to application of 3, 5, 7 Mg/ha of rice straw, methane emission increased by 46, 101, 190%, respectively, compared to that of the NPK plot. CONCLUSION(S): We obtained a quantitative relationship between $CH_4$ emission and the amount of rice straw applied from rice fields which could be described by polynomial regression of order 2. The emission scaling factor estimated by the relationship were in the range of IPCC GPG (2000).

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.293-305
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• 2009

Methane, as a greenhouse gas, is some 21~25 times more detrimental to the environmental than carbon dioxide. Landfills generally constitute the most important anthropogenic source, and methane emission from landfill was estimated as 35~73 Tg per year. Biological approaches using biocover (open system) and biofilter (closed system) can be a promising solution for older and/or smaller landfills where the methane production is too low for energy recovery or flaring and installation of a gas extraction system is inefficient. Methanotrophic bacteria, utilizing methane as a sole carbon and energy source, are responsible for the aerobic degradation (oxidation) of methane in the biological systems. Many bench-scale studies have demonstrated a high oxidation capacity in diverse filter bed materials such as soil, compost, earthworm cast and etc. Compost had been most often employed in the biological systems, and the methane oxidation rates in compost biocovers/boifilters ranged from 50 to $700\;g-CH_4\;m^{-2}\;d^{-1}$. Some preliminary field trials have showed the suitability of biocovers/biofilters for practical application and their satisfactory performance in mitigation methane emissions. Since the reduction of landfill methane emissions has been linked to carbon credits and trading schemes, the verified quantification of mitigated emissions through biocovers/biofilters is very important. Therefore, the assessment of in situ biocovers/biofilters performance should be standardized, and the reliable quantification methods of methane reduction is necessary.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.4
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• pp.275-288
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• 2009

The Korean government strengthened the environmental polices to manage and enhance Metropolitan Area air quality, and also has enforced "Special Act on Seoul Metropolitan Air Quality Improvement (SASMAQI)" issued in Dec. 2004. Recently government expanded the Seoul Metropolitan Air Quality Management District (SMAQMD) to the outskirts satellite cities of Seoul area through the "Revised Law Draft of SASMAQI". The SMAQMD has been alloted the allowable emission loads to the local governments on the basis of the carrying $PM_{10}$ capacity. However, in order to establish the effective air quality control strategy for $PM_{10}$, it is necessary to understand the corresponding sources which have a potential to directly impact ambient $PM_{10}$ concentration. To deal with the situations, many receptor methodologies have been developed to identify the origins of pollutants and to determine the contributions of sources of interests. The objective of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions at the metropolitan area. $PM_{10}$ samples were simultaneously collected at the 3 semi-industrialized local cities in the Seoul metropolitan area such as Hwasung-si, Paju-si, and Icheon-si sites from April 15 to May 31, 2007. The samples collected on the teflon membrane filter by one $PM_{10}$ cyclone sampler were analyzed for trace metals and soluble ions and samples on the quartz fiber filter by another sampler were analyzed for OC and EC. Source apportionment study was then performed by using a positive matrix factorization (PMF) receptor model. A total of 6 sources were identified and their contributions were estimated in each monitoring site. Contribution results on Hwasung, Paju, and Icheon sites were as follows: 33%, 27%, and 27% from soil source, 26%, 26%, and 21% from secondary aerosol source, 11%, 11%, and 12% from biomass burning, 12%, 6%, and 5% from sea salt, 7%, 15%, and 19% from industrial related source, and finally 11%, 15%, and 16% from mobile and oil complex source, respectively. This study provides information on the major sources affecting air quality in the receptor sites and thus it will help to manage the ambient air quality in the metropolitan area by establishing reasonable control strategies, especially for the anthropogenic emission sources.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.590-603
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• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.307-316
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• 2019

In the agricultural sector, greenhouse gas emissions vary depending on the interaction of all ecosystem changes such as soil environment, weather environment, crop growth, and anthropogenic farming activities. Agricultural sector greenhouse gas emissions resulting from many of these interactions are highly variable. Uncertainty-based evaluation that defines the interval with confidence level of greenhouse gas emission and absorption is necessary to take account of the variance characteristics of individual emissions, but research on uncertainty evaluation method is insufficient. This study aims to decide on the effect of reducing N₂O emissions from upland soils using an uncertainty-based approach. An uncertainty-based approach confirmed whether there was a difference between confidence intervals in the 5 different fertilizer treatment groups to reduce greenhouse gas emissions. Unlike the statistically significant test with three repetition averages, the uncertainty-based approach method estimated in this study is able to estimate the confidence interval considering the distribution characteristics of the emissions, such as the dispersion characteristics of individual emissions. Therefore, it is considered that the reliability of emissions can be improved by statistically testing the variance characteristics of emissions such as the uncertainty-based approach. It is hoped that the direction of the uncertainty-based approach for the effect of reducing greenhouse gas emissions in agriculture will be helpful in the future development of agricultural greenhouse gas emission reduction technology, adaptation to climate change, and further development of sustainable eco-social system.

• Atmosphere
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• v.31 no.5
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• pp.593-606
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• 2021

The Korea Meteorological Administration/National Institute of Meteorological Sciences (KMA/NIMS) has monitored atmospheric CO₂ at Anmyeondo (AMY) World Meteorological Organization (WMO) Global Atmosphere Watch Programme (GAW) regional station since 1999, and expanded its observations at Jeju Gosan Suwolbong station (JGS) in the South and at Ulleungdo-Dokdo stations in the East (ULD and DOK) since 2012. Due to a recent WMO CO₂ scale update and a new filter (NIMS) to select baseline levels at each station, the 22 years of CO₂ data are recalculated. After correction for the new CO₂ scale, we confirmed that those corrected records are reasonable within the compatibility goal (±0.1 ppm of CO₂) between KMA/NIMS and National Oceanic and Atmosphereic Administration (NOAA) flask-air measurements with the new scale. With the new NIMS filter, CO₂ baseline levels are now more representative of the large-scale background compared to previous values, which contained large CO₂ enhancements. Atmospheric CO₂ observed in South Korea is 4 to 8 ppm greater than the global average while the amplitude of seasonal variation is similar (10~13 ppm) to the amplitude averaged over a comparable latitude zone (30°N-60°N). Variations in CO₂ growth rate are also similar, increasing and decreasing similar to global values, as it reflects the net balance between terrestrial respiration and photosynthesis. In 2020, atmospheric CO₂ continued increasing despite the COVID-19 pandemic. Even though fossil emission was reduced (around -7% globally), we still emitted large amounts of anthropogenic CO₂. Overall, since CO₂ has large natural variations and its source was derived from not only fossil fuel but also biomass burning, the small fossil emission reduction could not affect the atmospheric level directly.

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.1
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• pp.3-26
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• 2010

The European Union(EU) has recently introduced its Directive 2008/101/EC to include aviation in the EU ETS(emissions trading system). As an amendment to Directive 2003/87/EC that regulates reduction of the green house gas(GHG) emissions in Europe in preparation for the Kyoto Protocol, 1997, it obliges both EU and non-EU airline operators to reduce the emission of the carbon dioxide(CO2) significantly in the year 2012 and thereafter from the level they made in 2004 to 2006. Emission allowances allowed free of charge for each airline operator is 97% in the first year 2012 and 95% from 2013 and thereafter from the average annual emissions during historical years 2004 to 2006. Taking into account the rapid growth of air traffic, i.e. 5% in recent years, airlines operating to EU have to reduce their emissions by about 30% in order to meet the requirements of the EU Directive, if not buy the emissions right in the emissions trading market. However, buying quantity is limited to 15% in the year 2012 subject to possible increase from the year 2013. Apart from the hard burden of the airline operators, in particular of those from non-European countries, which is not concern of this paper, the EU Directive has certain legal problems. First, while the Kyoto Protocol of universal application is binding on the Annex I countries of the Climate Change Convention, i.e. developed countries including all Member States of the European Union to reduce GHG at least by 5% in the implementation period from 2008 to 2012 over the 1990 level, non-Annex I countries which are not bound by the Kyoto Protocol see their airlines subjected to aircraft emissions reductions scheme of EU when operating to EU. This is against the provisions of the Kyoto Protocol dealing with the emissions of GHG including CO2, target of the EU Directive. While the Kyoto Protocol mandates ICAO to set up a worldwide scheme for aircraft emissions to contribute to stabilizing GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system, the EU ETS was drawn up outside the framework of the international Civil Aviation Organization(ICAO). Second, EU Directive 2008/101 defines 'aviation activities' as covering 'flights which depart from or arrive in the territory of a Member State to which the [EU] Treaty applies'. While the EU airlines are certainly subject to the EU regulations, obliging non-EU airlines to reduce their emissions even if the emissions are produced during the flight over the high seas and the airspace of the third countries is problematic. The point is whether the EU Directive can be legally applied to extra-territorial behavior of non-EU entities. Third, the EU Directive prescribes 2012 as the first year for implementation. However, the year 2012 is the last year of implementation of the Kyoto Protocol for Annex I countries including members of EU to reduce GHG including the emissions of CO2 coming out from domestic airlines operation. Consequently, EU airlines were already on the reduction scheme of CO2 emissions as long as their domestic operations are concerned from 2008 until the year 2012. But with the implementation of Directive 2008/101 from 2012 for all the airlines, regardless of the status of the country Annex I or not where they are registered, the EU airlines are no longer at the disadvantage compared with the airlines of non-Annex I countries. This unexpected premium for the EU airlines may result in a derogation of the Kyoto Protocol at least for the year 2012. Lastly, as a conclusion, the author shed light briefly on how the Korean aviation authorities are dealing with the EU restrictive measures.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.139-149
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• 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.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.145-157
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• 2012

In this study, we simulated a carbon flux model, so called Vegetation Integrated Simulator for Trace gases (VISIT) using Spatio-temporal Environmental Information, to estimate carbon budgets of vegetation ecosystem in South Korea. As results of the simulation, the model estimated that the annual-average gross primary production (GPP), net primary production (NPP) for 10 years were $91.89Tg\;C\;year^{-1}$, and $40.16Tg\;C\;year^{-1}$, respectively. The model also estimated the vegetation ecosystems in South Korea as a net carbon sink, with a value of $3.51Tg\;C\;year^{-1}$ during the simulation period. Comparing with the anthropogenic emission of South Korea, vegetation ecosystems offsets 3.3% of human emissions as a net carbon sink in 2007. To estimate the carbon budget more accurately, it is important to prepare reliable input datasets. And also, model parameters should be calibrated through comparing with various independent method. The result of this study, however, would be helpful for devising ecosystem management strategies that may help to mitigate global climate change.