• Korean Journal of Materials Research
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• v.18 no.2
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• pp.73-76
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• 2008

[ $SF_6$ ] gas has been widely used as an insulating, cleaning and covering gas due to its outstanding insulating feature and because of its inert properties. However, the global warming potential of $SF_6$ gas is extremely high relative to typical global warming gases such as $CO_2$, CFCs, and $CH_4$. For these reasons, it is necessary to separate and collect waste $SF_6$ gas. In this study, the effects of a surfactant (Tween) on the formation rate of $SF_6$ gas hydrates were investigated. The $SF_6$ gas hydrate formation rate increased with the addition of Tween and showed a nearly 6.5 times faster hydrate formation rate with an addition of 0.2 wt.% Tween compared to an addition of pure water. This is believed to be due to the increased solubility of $SF_6$ gas with the addition of the surfactant. It was also found that $SF_6$ gas hydrate in the surfactant solution showed two-stage hydrate formation rates with a formation rate that increased rapidly in the 2nd stage.

• Journal of Ecology and Environment
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• v.33 no.3
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• pp.195-204
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• 2010

In the study, the effects of elevated $CO_2$ and temperature on the photosynthetic characteristics, chlorophyll content, nitrogen content, carbon content, and C/N ratio of Phytolacca insularis and Phytolacca americana were examined under control (ambient $CO_2+$ ambient temperature) and treatment (elevated $CO_2+$ elevated temperature) for 2 years (2008 and 2009). The photosynthetic rate, transpiration rate and water use efficiency of two plant species were higher under the treatment than the under the control. The stomatal conductance of P. insularis was higher under the control, but that of P. americana was not significantly affected by $CO_2$ and temperature under the treatment. The chlorophyll contents of two species were decreased about 72.5% and 20%, respectively, by elevated $CO_2$ and temperature. The nitrogen contents of two species were not significantly altered by increase in $CO_2$ and temperature. The carbon contents of the two species were higher under the treatment than under the control. The C/N ratio of P. insularis was higher under the treatment but that of P. americana was not significantly affected by $CO_2$ and temperature. These results demonstrated that the physiological responses of P. insularis native plants might be more sensitively influenced by a $CO_2$-mediated global warming situation than those of the P. americana invasive plants.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.1023-1029
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• 2017

We studied the distribution of air temperature using the high density urban climate observation network data of Daegu. The observation system was established in February 2013. We used a total of 38 air temperature observation points (23 thermometers and 18 AWSs). From the distribution of monthly averaged air temperatures, air temperatures at the center of Daegu were higher than in the suburbs. The daily minimum air temperature was more than or equal to $25^{\circ}C$ and the daily maximum air temperature was more than or equal to $35^{\circ}C$ at the elementary school near the center of Daegu. Also, we compared the time elements, which are characterized by the diurnal variation of surface air temperature. The warming and cooling rates in rural areas were faster than in urban areas. This is mainly due to the difference in surface heat capacity. These results indicate the influence of urbanization on the formation of the daily minimum temperature in Daegu.

• ALGAE
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• v.35 no.4
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• pp.375-388
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• 2020

Ocean acidification and warming, identified as environmental concerns likely to be affected by climate change, are crucial determinants of algal growth. The ichthyotoxic raphidophytes Chattonella species are responsible for huge economic losses and environmental impact worldwide. In this study, we investigated the impact of CO2 on the thermal performance curves (TPCs) of Chattonella marina and Chattonella ovata grown under temperatures ranging from 13 to 34℃ under ambient pCO2 (350 μatm) and elevated pCO2 (950 μatm). TPCs were comparable between the species or even between pCO2 levels. With the exception of the critical thermal minimum (CTmin) for C. ovata, CTmin for C. marina and the thermal optimum (Topt) and critical thermal maximum (CTmax) for both species did not change with elevation of pCO2 levels. While CO2 enrichment increased the maximum photosynthetic rates (Pmax) up to 125% at the Totp of 30℃, specific growth rates were not significantly different under elevated pCO2 for the two species. Overall, C. ovata is likely to benefit from climate change, potentially widening its range of thermal tolerance limit in highly acidic waters and contributing to prolonged phenology of future phytoplankton assemblages in coastal waters.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.146-147
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• 2021

An increase in carbon emissions leads to the problem of global warming and is an issue to be solved in other countries. The problem of carbon dioxide has many effects not only on global warming but also on people. According to the World Health Organization (WHO), 4.3 million people have died because harmful substances generated indoors cannot be discharged to the outside and accumulate in the human body through the respiratory tract. In response to this situation, in order to reduce the generation of pollutants in the building itself, soak into lightweight bubble concrete to adsorb and purify indoor pollutants, mix charcoal, investigate the appropriate amount and physical characteristics, and check carbon dioxide This is an experiment for grasping the adsorption capacity, and the results are as follows. As the replacement rate of rice husk charcoal increased, the compressive strength tended to decrease, and the carbon dioxide reduction rate tended to increase. It is judged that the charcoal of rice husks shows a low density and the physical adsorption is smooth due to the porous structure. Since it is excellent in the basic physical properties and carbon dioxide adsorption surface of this experiment, it is judged that it has sufficient potential for use as an indoor finishing material.

• Atmosphere
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• v.33 no.5
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• pp.505-517
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• 2023

This study investigates the impacts of carbon neutrality and air quality control policies on near-term climate change in East Asia, by examining three Shared Socioeconomic Pathways (SSPs) scenarios from five climate models. Specifically, low carbon and strong air quality control scenario (SSP1-1.9), high carbon and weak air quality control scenario (SSP3-7.0), and high carbon and strong air quality control scenario (SSP3-7.0-lowNTCF) are compared. For these scenarios, the near-term climate (2045-2054 average) changes are evaluated for surface air temperature (SAT), hot temperature extreme intensity (TXx), and hot temperature extreme frequency (TX90p). In all three scenarios, SAT, TXx, and TX90p are projected to increase in East Asia, while carbon neutrality reduces the increasing rate of SAT and hot temperature extremes. Air quality control strengthens the warming rate. These opposed mitigation effects are robustly forced in all model simulations. Nonetheless, the impact of carbon neutrality overcomes the impact of air quality control. These results suggest that fast carbon neutrality, more effective than an air quality control policy, is necessary to slowdown future warming trend in East Asia.

• Journal of Environmental Science International
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• v.33 no.6
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• pp.367-382
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• 2024

Alpine and subalpine plants are isolated and distributed in mountaintop areas at high altitudes and, are among the species most vulnerable to global warming. If the rate of warming continues at its current rate, it is highly likely that this species will be unable to find new refugia and will be the last to go extinct in their current habitats. Therefore, research on the distribution and diversity of alpine and subalpine plants is urgently needed and is important from the perspective of biodiversity conservation. Therefore, this study focused on the distribution of alpine and subalpine plants native to national parks. Alpine and subalpine plants distributed across the 12 national parks accounted for approximately half (47.78%) of all alpine plants in Korea. The average relative frequency of occurrence was 0.23, plant similarity between national parks was 37.19%, and beta diversity was 0.63. The number of species was positively correlated with the latitude, elevation, and area of the national park. Thus the geographical distributions of alpine and subalpine plants haves distinct spatial specificities and physical environmental differences.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.1-10
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• 1993

A brief description on the greenhouse gases, the greenhoue effect, sea level changes, forcing of climate, the history of Earth's changing climate based on the IPCC REPORT and the records of the recent variation of the climate in the Republic of Kore is presented here for help enhancing awareness of the issues. The climate of the Earth has the potential to be changed on all timescales by the fluctuations of the concentrations of radioactively active greenhouse gases, solar radiation, aerosols and albedo. However, the rate of the recent global warming seems to be larger and rapid than any have occurred thorughout recorded history enough to draw the world-wide attention and worry concerned with the theme of environment and development. There are still uncertainties in the predictions relating to the timing, magnitude and the pattern of the climatic change due to the current incomplete understanding of various aspects of the complex processes. Nonetheless, the scientific results avaliable is sufficient to allow for decisive precautionary measures to be taken.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.523-537
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• 2008

In Korea, the global warming leads to more frequent high temperature region. increasing the need for research into physical damage caused by high temperature. We therefore analyzed the differences of mortality, caused by extreme heat, among gender and age. We also examined the trend of mortality from high temperature-sensitive diseases. Women are more affected by exposure to high temperature than are men; People over 65 years old have higher mortality rate (1.5 times) than under 65. As for high temperature-related diseases, cerebrovascular disease was the number one cause of death, and chronic lower respiratory disease and cardiovascular disease followed.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.36-42
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• 2021

When the landfill gas generated at the landfill site is released into the atmosphere, methane gas with a high global warming potential is emitted, which adversely affects climate change. When methane contained in landfill gas is used as fuel for internal combustion engines and burned to generate electricity, it is emitted into the atmosphere in the form of carbon dioxide, which can contribute to lowering the global warming potential. Therefore, in order to use the landfill gas as fuel for power generation using an internal combustion engine, it is important to increase the thermal efficiency of the engine. Thus, it is necessary to use a fuel supply system in which gas is injected using an electronically controlled injector at an intake port for each cylinder rather than a fuel supply technology using the conventional mixer technology. In order to use the electronically controlled gas injection method, it is important to accurately measure the mass flow rate according to the conditions of using landfill gas. For this, a study was conducted to measure the injection amount and calculate them in order for the intake port gas injection of landfill gas.