• Advances in aircraft and spacecraft science
• /
• v.1 no.3
• /
• pp.311-330
• /
• 2014

Environmental impact of aircraft emissions can be addressed in two ways. Air quality impact occurs during landings and takeoffs while in-flight impact during climbs and cruises influences climate change, ozone and UV-radiation. The aim of this paper is to investigate airports related local emissions and fuel consumption (FC). It gives flight path optimization model linked to a dispersion model as well as numerical methods. Operational factors are considered and the cost function integrates objectives taking into account FC and induced pollutant concentrations. We have compared pollutants emitted and their reduction during LTO cycles, optimized flight path and with analysis by Dopelheuer. Pollutants appearing from incomplete and complete combustion processes have been discussed. Because of calculation difficulties, no assessment has been made for the soot, $H_2O$ and $PM_{2.5}$. In addition, because of the low reliability of models quantifying pollutant emissions of the APU, an empirical evaluation has been done. This is based on Benson's fuel flow method. A new model, giving FC and predicting the in-flight emissions, has been developed. It fits with the Boeing FC model. We confirm that FC can be reduced by 3% for takeoffs and 27% for landings. This contributes to analyze the intelligent fuel gauge computing the in-flight fuel flow. Further research is needed to define the role of $NO_x$ which is emitted during the combustion process derived from the ambient air, not the fuel. Models are needed for analyzing the effects of fleet composition and engine combinations on emission factors and fuel flow assessment.

• Journal of Climate Change Research
• /
• v.6 no.4
• /
• pp.367-377
• /
• 2015

This study analyzed the effectiveness of China's policy to reduce of sulfur dioxide. China's $12^{th}$ Five-year plan on national economic and social development emphasized environmental protection and low-carbon economic development. Sulfur dioxide was one of the major gases to affect air pollution and climate change and its control became a key policy agenda in the environment and energy sector. As the absolute amount of sulfur dioxide emissions in China came from the industrial sector, the control of the coal-based energy was especially urgent. This study analyzed the factors that influenced the sulfur dioxide emissions and the policy effects to reduce sulfur dioxide in China from 2003 to 2012 based on regional data. The air pollution treatment investments showed the biggest impact together with energy conservation policy in reducing sulfur dioxide emissions. However, pollutant emissions charge did not show a relevant policy effectiveness in all regions as the amount of charge would be smaller than economic benefit from non-compliance. Rationalizing pollutant emissions charge is, therefore, a key policy task for further reduction of sulfur dioxide emissions.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.2
• /
• pp.146-153
• /
• 2004

A Promising new approach to achieve low pollutant emissions and improvement of flame stability is tested experimentally using a cyclone jet hybrid combustor employing both premixed and diffusion combustion mode. Three kinds of nozzle are tested for mixing enhancement of fuel and air. The LNG (Liquified Natural Gas) is used as a fuel. The combustor is operated by two methods. One is DC (Diffusion Combustion) mode generated swirl flow by air as general swirl combustor, and the other is HC (Hybrid Combustion) mode. The HC mode consists of diffusion jet flame of axial direction and premixed cyclone flame of tangential direction in order to stabilized the diffusion jet flame. The results showed that the flame stability of HC mode is significantly enhanced than that of DC mode through the change of mixing characteristics by modifications of fuel nozzle. In addition, the reductions of CO and NOx emission in HC mode, as compared with that for the DC mode, is large than about 50% in stable region. Also, even using the low calorific fuel as $CO_2$-blended gas, it is identified that the cyclone jet hybrid combustor has the high performance of flame stability.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.1
• /
• pp.1-9
• /
• 2013

Hazardous Air Pollutants (HAPs) are difficult to measure, analyze and assess for risk because of low ambient concentrations and varieties. Types of HAPs are Volatile organic compounds (VOCs), Polycyclic aromatic hydrocarbon (PAHs) and Aldehydes. HAP emissions from vehicles are a contributor to serious adverse health effects in urban areas. In this study, hazardous air pollutant emissions from road transport vehicles by Non-methane volatile organic compounds (NMVOC) weight fraction and PAHs emission factors are estimated in 2008. The top-five-most hazardous air pollutant emissions were estimated to toluene 864.3 ton/yr, acrolein 690.6 ton/yr, acetaldehyde 554.5 ton/yr, formaldehyde 498.7 ton/yr, propionaldehyde 421.6 ton/yr in 2008. The results for a cancer and non-cancer risk assessment of HAPs emissions show that the major cancer driver is formaldehyde and the non-cancer driver is acrolein.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.4
• /
• pp.347-361
• /
• 2003

Sulfur dioxide (SO$_2$), ozone, total suspended particulates (TSP) and PM$_{2.5}$ were measured at Deokjeok Island in the Yellow Sea during April 1999 to June 2000. Although the emission amount of air pollutants is quite low in this small island of 36 km$^2$ with 1.4 thousand inhabitants, there are pollutant sources such as an oil -firing power plant and a wharf for ferryboat. The island is also influenced from the emissions from the greater Seoul area in the east and from China in the west. In order to characterize the pollutant variations due to interactions between transport and local emissions. the correlation between variations of SO$_2$ and ozone was investigated. Mass and ion concentrations of TSP and PM$_{2.5}$ were examined on selected episode days of positive and negative correlations between the two gaseous species in spring and winter. The effects of transport were pronounced on the days of positive correlation in spring with higher concentrations of ozone and PM$_{2.5}$. TSP concentrations were also high on these days because of high wind speeds. On the days of negative correlation in spring, frequent fog associated with low wind speeds facilitated SO$_2$ oxidation and increased sulfate accompanied with decrease in nitrate in PM$_{2.5}$ and chloride in TSP. This latter phenomena was noticeable since it showed that chemical composition of fine particles could be significantly altered not only during the transport but also by local environment.ronment.

• 한국연소학회:학술대회논문집
• /
• 2013.06a
• /
• pp.37-40
• /
• 2013

Hydrogen-dimethy ether (DME) and hydrogen-diesel compression ignition engine combustion were investigated and compared each other in a single cylinder compression ignition engine. Hydrogen and DME were used as low carbon alternative fuels to reduce green house gases and pollutant. Hydrogen was injected at the intake manifold with an injection pressure of 0.5 MPa at fixed injection timing, $-210^{\circ}CA$ aTDC. DME and diesel were injected directly into the cylinder through the common-rail injection system at injection pressure of 30 MPa. DME and diesel inejction timing was varied to find the optimum CI combustion to reduce CO, HC and NOx emissions. When DME was injected early, CO and HC emissions were high while NOx emission was low. Fuel consumption, heat release rate, and exhaust emissions were measured to analyze each combustion characteristics of each ignition promoter. Fuel consumption was decreased when diesel was used as an ignition promoter. This is due to the lower volatility of diesel which created more stratified charge than DME.

• Journal of ILASS-Korea
• /
• v.21 no.4
• /
• pp.214-222
• /
• 2016

Changes in road infrastructure affect driving patterns and pollutant emission characteristics. we analyzed the changes in driving patterns and pollutant emission characteristics of the driving route via measured driving patterns at year 2009 and 2016. Since 2009, there has been an increase in population and traffic demand, including residential areas and industrial facilities. Traffic conditions were improved such as the opening of the highway Inter-Change to Seoul and the construction of underground driveway. As a result, the average vehicle speed increased. More detail comparisons have made on the changes of the underground driveway section and the crossroad section, which are expected to have significant changes in the transportation infrastructure. The vehicle speed distribution of the underground driveway changed from low speed to high speed, and the increase of the time spent at the high speed and high load caused the increase of NOx emissions. The vehicle speed also increased at the crossroad section, and the consequence NOx and $CO_2$ emissions decreased. It is mainly because the decreased time spent at idle, which results from the proper traffic demand management at this area.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.7
• /
• pp.905-917
• /
• 2021

Atmospheric pollutant emissions, mainly exhaust gas emissions from vessels, and the resultant social costs of pollution in the Korean harbor cities of Incheon, Mokpo, Gwangyang, Busan and Ulsan, are examined in this study, and the need for an emissions reduction plan is highlighted. Busan had several vessels entering its port, while Mokpo had few vessels, yet the vessels emission contribution was high in both the cities. Ulsan had world-class heavy-chemical industries, Gwangyang had steel mills and Incheon had a manufacturing industry and more vessels entering its port than Mokpo, yet the emission contribution was low in these cities. By calculating exhaust gas emissions from the vessels, it was found that CO₂ was the highest, followed by NOx and SOx. By vessel type, Busan, Ulsan, and Incheon had more oil tank vessels, Gwangyang had more cargo vessels, and Mokpo had more ferries. As a result of social cost, Busan paid the highest, while the highest emission was PM. The use of low-sulfur oil can directly reduce PM and, SOx emissions and indirectly reduce NOx emissions. However, in order to reduce high CO₂ emissions, only low-sulfur oil will not help. Therefore, the study suggested the need for reduction plan that use of fossil fuels, by using alternative maritime power (AMP).

• Journal of the Korean Society of Combustion
• /
• v.18 no.1
• /
• pp.27-33
• /
• 2013

Hydrogen-dimethy ether(DME) partially premixed compression ignition(PCCI) engine combustion was investigated in a single cylinder compression ignition engine. Hydrogen and DME were used as low carbon alternative fuels to reduce green house gases and pollutant. Hydrogen was injected at the intake manifold with an injection pressure of 0.5 MPa at fixed injection timing, $-210^{\circ}CA$ aTDC. DME was injected directly into the cylinder through the common-rail injection system at injection pressure of 30 MPa. DME inejction timing was varied to find the optimum PCCI combustion to reduce CO, HC and NOx emissions. When DME was injected early, CO and HC emissions were high while NOx emission was low. As the DME injection was retarded, the CO and HC emissions were decreased due to high combustion efficiency. NOx emissions were increased due to the high in-cylinder temperature. When DME were injected at $-30^{\circ}CA$ aTDC, reduction of HC, CO and NOx emissions was possible with high value of IMEP.

• 한국연소학회:학술대회논문집
• /
• 2003.05a
• /
• pp.215-222
• /
• 2003

Mild combustion or Flameless oxidation(FLOX) have been considered as one of the most prospective clean-combustion technologies to meet both the targets of high process efficiency and low pollutant emissions. A mild combustor with high air preheating and strong internal exhaust gas recirculation is characterized by relatively low flame temperature, low NOx emissions, no visible flame and no sound. In this study, the Steady Flamelet Approach has been applied to numerically analyze the combustion processes and NOx formation in the mild combustor. The detailed discussion has been made for the basic characteristics of mild combustor, numerical results and limitation of the present combustion modeling.