• Journal of Korean Society for Atmospheric Environment
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• v.22 no.2
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• pp.209-222
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• 2006

Odor problems brought about by deteriorating air quality occur in areas surrounding landfills because VOCs emissions from landfills are exhausted through surface soil and gas vents. Due to these factors, monitoring of VOCs emissions from landfills are essential. However, only a few studies have been carried out to assess VOCs emissions from landfills. A comprehensive approach to this problem is definitely warranted. In this study, we estimated BTEX emissions from 7 landfill sites in Korea using field experiments and LandGEM(Landfill Gas Emission Model), which is the USA EPA(Environmental Protection Agency)-recommended model for landfill gas emission estimation. For this purpose, we suitably modified the model's major input parameters $L_0$ and k according to 3 classes based on landfill scale after considering the characteristics of field experiments and LandGEM data. Consequently, we estimated VOCs emissions from landfills for cities, provinces and all of Korea alter modifying $L_0$ & k using LandGEM. Through the results of this study, we obtained essential basic data with respect to present conditions which will help us understand VOCs emissions from landfills in Korea.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.1-6
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• 2003

Engine emission regulations are becoming more stringent nowadays. In cold transient regime, about 80% THC is exhausted to the atmosphere in the first 200s (US FTP cycles). Accordingly, reducing emission levels in the cold period immediately after the engine start before the catalysts reach their working temperature will be an especially critical factor in meeting more stringent regulations in the future. In this study, the total hydrocarbon quantities are measured using a Fast FID with gasoline fuel for a 4-cylinde. Sl engine, including Secondary Air Injection (SAI) system. Commercial SAI device's direction is reverse to the exhaust flow. In this study, a swirl flow type SAI system which is positioned between the exhaust manifold and exhaust port, was developed. We compared the swirl type secondary air injection with a commercial secondary air injection of .everse flow. The swirl type SAI showed better results in reducing HC by 26% than the commercial flow type SAI of reverse flow which was caused by the better mixing between the exhaust gas and the secondary air.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.132-139
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• 2010

This paper describes an investigation of the performance and emission characteristics of a commercial cylinder direct injection diesel engine operating on natural gas with pilot diesel ignition. Engine tests for variations in the pilot injection timing were performed at an engine speed of 1500 rpm. This study showed that the performance of the dual-fuel diesel engine increased as the engine load increased and as the pilot diesel injection timing angle advanced. The peaks of cylinder pressure, pressure rise rate, and heat release rate all increased while the fuel ignition timing advanced with the pilot injection timing. The engine operation was stable, and the least smoke was produced at a pilot injection timing of $12^{\circ}$ before top dead center. NOx emissions were only exhausted under high-load conditions, and they increased as the pilot injection timing angle advanced.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.85-88
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• 2003

Polycyclic aromatic hydrocarbons (PARs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRT AP) of Europe. A method of the gas chromatographic-mass spectrometric (GC-MS) determination of PARs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PARs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PARs sewage sludge samples varied from 2.44 to 4.82 ${\mu}g$/g. Concentration of emission carcinogen PARs(PARcarc), such as Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a, h)anthracene and Indeno(1, 2, 3-cd)pyrene ranged from 0.62 to 1.03 ${\mu}g$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PARs and $\sum$PAHcarc from sewage treatment plants had several pathway each by-products. In the ocean dumping, PAHs and $\sum$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year. In recycle, PAHs and $\sum$PAHcarc emissions were 98.36 kg/year and 428.87 kg/year. In the landfill, PAHs and $\sum$PAHcarc emissions were 190.40 kg/year and 830.21 kg/year. In the incineration, PAHs and $\sum$PAHcarc emission were 33.10 kg/year and 830.21 kg/year. (In case of incineration, the whole provisions of PARs and $\sum$PAHcarc contained to flowed in sludge was supposed to be exhausted to environment through exhaust after incineration.)

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.61-69
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• 2002

To meet stringent LEV and ULEV emission standards, a considerable amount of development work was necessary to ensure suitable efficiency and durability of catalyst systems. The main challenge is to cut off the engine cold-start emissions. It is known that up to 80% of the total hydrocarbons(THC) are exhausted within the first five minutes in case of US FTP 75 cycle. Close-Coupled Catalyst(CCC) provides fast light-off temperature by utilizing the energy in the exhaust gas. However, if some malfunction occurred at engine operation and the catalyst temperature exceeds 1050$\^{C}$, the catalytic converter is deactivated and shows the poor conversion efficiency. This paper presents effEcts of engine operating conditions on catalytic converter temperature in a SI engine, which are the indications of catalytic deactivation. Exhaust gas temperature and catalyst temperature were measured as a function of air/fuel ratio, ignition timing and misfire rates. Additionally, light-off time was measured to investigate the effect of operating conditions. It was found that ignition retard and misfire can result in the deactivation of the catalytic converter, which eventually leads the drastic thermal aging of the converter. Significant reduction in light-off time can be achieved with proper control of ignition retard and misfire, which can reduce cold-start HC emissions as well.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.800-805
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• 2001

Recently, our world is faced with very serious and hard problems related to the air pollution due to the exhaust emissions of the diesel engine. So, lots of researchers have studied to reduce the exhaust emissions which influenced the environment strong. In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for diesel engine. And, we tried to analysis the quantities of the low and high hydrocarbon among the exhaust emissions in diesel engine. It have been investigated by the quantitative analysis of the hydrocarbon $C_1\simC_6$ using the gas chromatography. This study carried out by comparing the chromatogram with diesel fuel and diesel fuel blended DGM(diethylene glycol dimethyl ether) 5%. The results of this study show that the hydrocarbon $C_1\simC_6$ among the exhaust emissions of the mixed fuels are exhausted lower than those of the diesel fuel at the all load and speed. In particular, high boiling point hydrocarbons such as $C_5$ and $C_6$ were reduced remarkably in high speed and load region.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.9
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• pp.506-515
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• 2013

The PFT (PerFluorocarbon Tracergas Technique) is of advantage to field surveys for evaluating the ventilation condition, due to its simplicity and convenience. On the other hand, it requires researchers to make some additional considerations that include uncertainties, such as the substance concentration distribution in indoor air, representativeness of a sampler, deviation of emission sources, and analysis error. In this study, the PFT and $CO_2$ tracer gas methods were applied simultaneously, to evaluate the accuracy of PFT on six ventilation conditions in the three-storied detached house. The air exchange and the outdoor air introduction a between and into zones were measured. As the results, deviations of PFT concentration distributions were observed at a sufficiently low level for an accurate determination for a house where the interior height was large, and there were relatively many partition walls. However, when a uniform airflow appeared in the indoor air, it was also validated that the indoor air would be exhausted without sufficient mixing, and consequently the measurement error of the PFT would be large.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.85-91
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• 2002

Workers who work at indoor and outdoor environment near busy road are suspected to be exposed to high-elevated air pollutant levels during working hours. This study evaluated the working-time nitrogen dioxide ($NO_2$) exposure for workers (repairmen and polishers) of shoe-stalls. Since shoe-stalls have particularly been located near busy road in Korea, workers might be high exposure to $NO_2$ from traffic exhaust as well as indoor sources of shoe-stall such as portable gas range (butane gas) during working hours. In this study, we measured the indoor and outdoor $NO_2$ concentrations of shoe-stalls. Simultaneously, outdoor $NO_2$ concentrations of building through sidewalk from shoe-stall were measured. High $NO_2$ exposure for workers of shoe-stalls was considered to be inflow of outdoor source of exhausted emission from vehicles and indoor source from usage of gas range to polish the shoe. Indoor/outdoor $NO_2$ concentration ratio ($0.94{\pm}0.22$) in Seoul was higher than that ($1.06{\pm}0.34$) in Asan, because ambient $NO_2$ level was high in Seoul and usage of gas range was prevalent in Asan. According to $NO_2$ concentrations by distance from roadside to building through sidewalk, $NO_2$ concentrations showed the decreased trend with distance. The results of this study can be utilized by municipal authorities in urban planning for evaluating effects of future traffic planning and land use.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.93-101
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• 2006

This research makes a new attempt to apply the activated seawater by electrolysis in the development of two-stage wet scrubber system to control the exhaust gas of large marine diesel engines. First, with using only seawater that is naturally alkaline (pH typically around 8.1). the $SO_2\;and\;SO_3$ are absorbed by relatively high solubility compared to other components of exhaust pollutants, and PM (Particulate Matter) is removed through direct contact with sprayed seawater droplets. Besides, the electrolyzed alkaline seawater by electrolysis, which contains mainly NaOH together with alkali metal ions $(i.e.\;Na^+,\;Mg^{2+},\;Ca^{2+})$, is used as the absorption medium of NOx and $CO_2$. Especially, to increase NOx absorption rate into the alkaline seawater. nitric oxide (NO) is adequately oxidized to nitrogen dioxide $(NO_2)$ in the acidic seawater, which means both volume fractions are adjusted to identical proportion. The results found that the strong acidic seawater was a valid oxidizer from NO to $NO_2$ and the strong alkaline seawater was effective in $CO_2$ absorption In the scrubber test, the SOx reduction of nearly $100\%$ could be achieved and also led to a sufficientPM reduction. Hence, the author believes that applying seawater and its electrolyte would bring the marine air pollution control system to an economical measure. Additionally it is well known that NOx and SOx concentration has a considerable influence on the $N_2O$ emission of green house gas. Although the $N_2O$ concentration exhausted from diesel engines is not as high, the green house gas effect is around 300 times greater than an equivalent volume of $CO_2$. Therefore, we investigated the $N_2O$ removal efficiency with using the electrolyzed seawater too. Finally this research would also plan to treat the effluent by applying electro-dialysis and electro-flotation technique s in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.498-503
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• 2012

It happens that the fuel is not injected when the driver doesn't push the acceleration pedal of vehicle with engine speed higher than 1,500rpm above the mid range of vehicle speed. This is called "fuel-cut function" and almost every modern vehicle is equipped with this function. This is activated frequently on the downhill area of highway and the quantity of vehicle-exhausted $CO_2$ gas can be zero on this area. With this fuel-cut function on the test highway, $CO_2$ gas from passenger car(2,000cc engine volume) can be reduced up to 4%. The fuel-cut function with CRUISE made in company AVL is simulated to find the most effective driving pattern on the downhill area. By simulating with CRUISE software, it is found that the lower limit of vehicle speed for fuel-cut should be raised to improve the fuel economy on the steeper downhill road. The fuel economy can be most economical when fuel-cut driving and reacceleration are completed on the section of downhill road.