• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.4 no.1
• /
• pp.11-23
• /
• 2000

Photochemical air quality models are essential tools in predicting future air quality and assessing air pollution control strategies. To evaluate air quality using a photochemical air quality model, emission inventories are important inputs to these models. Since most emission inventories are provided at a county-level, these emission inventories need to be geographically allocated to the computational grid cells of the model prior to running the model. The conventional method for the spatial allocation of these emissions uses "spatial surrogate indicators", such as population for mobile source emissions and county area for biogenic source emissions. In order to examine the applicability of such approximations, more detailed spatial surrogate indicators were developed using Geographic Information System(GIS) tools to improve the spatial allocation of mobile and boigenic source emissions, The proposed spatial surrogate indicators appear to be more appropriate than conventional spatial surrogate indicators in allocating mobile and biogenic source emissions. However, they did not provide a substantial improvement in predicting ground-level ozone(O3) concentrations. As for the carbon monoxide(CO) concentration predictions, certain differences between the conventional and new spatial allocation methods were found, yet a detailed model performance evaluation was prevented due to a lack of sufficient observed data. The use of the developed spatial surrogate indicators led to higher O3 and CO concentration estimates in the biogenic source emission allocation than in the mobile source emission allocation.llocation.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2011.10a
• /
• pp.39-40
• /
• 2011

The 62nd session of the MARINE Environment Protection Committee was held in London from 11 to 15 July 2011. Mandatory measures to reduce emissions of greenhouse gases (GHGs) from international shipping were adopted at the Committee. The amendment to MARPOL Annex VI includes a new chapter 4 to make mandatory the Energy Efficiency Design Index (EEDI) for new ships and the Ship Energy Efficiency Management Plan (SEEMP) for all ships. This first mandatory measures on energy efficiency will enter into force on 1 January 2013. This amendment to MARPOL Annex VI will significantly influences the vast majority of the international maritime community. This paper mainly discusses the main results of MEPC 62nd session including the recent Emission Control Area.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.2
• /
• pp.115-119
• /
• 2011

A tip-type carbon nanotube(CNT)-based field emitter was studied to consider it as electron source for micro-focused x-ray tube. The CNT was grown directly on a metal (tungsten) substrate by using an inductively coupled plasma-chemical vapor deposition (ICP-CVD) method. Prior to CNT growth, the metal substrate was etched to have various tip angles from $10^{\circ}$ to $180^{\circ}C$ (flat-type). The morphologies and microstructures of all the grown CNTs were analyzed via field-emission SEM. Furthermore, the effects of substrate tip-angles on the emission properties of CNT-based field emitters were characterized to estimate the maximum current density, the turn-on voltage, and the spatial distribution of electron beams. Prolonged long-term stability testing of the CNT emitters was also performed. All the experiment results obtained from this study indicated why a tip-type CNT emitter, compared with a flat-type CNT emitter, would be more desirable for a micro-focused x-ray system, in terms of the emission current level, the focused beam area, and the emission stability.

• Journal of Korean Society for Atmospheric Environment
• /
• v.31 no.6
• /
• pp.562-572
• /
• 2015

$NO_x$ emissions from diesel vehicles have been regarded as a main cause of high $NO_2$ concentration in metropolitan area. Recent studies have shown that the on-road $NO_x$ emissions of diesel vehicles are quite higher than the emission limits specified with the pre-defined test method for emission certification. To reduce air pollutants effectively, the discrepancy of emissions in certification and real-driving conditions should be tackled. In this study, the real-driving emissions have been estimated with portable emission measurement system (PEMS). The results of this study have shown that the on-road $NO_x$ emissions from diesel vehicles have been decreased as the introduction of stricter emission regulation, EURO-6, but additional reduction should be still required and robust technologies should be applied to control $NO_x$ in real-driving conditions. RDE-LDV (Real Driving Emission - Light Duty Vehicles) test method being developed in the European Union can represent excessive on-road $NO_x$ emissions of diesel vehicles as applied emission technologies and can be a solution to remove discrepant $NO_x$ emissions between certification and Korean real-driving conditions. Among the $NO_x$ reduction technologies for EURO-6 diesel vehicles, selective catalytic reduction (SCR) system has shown the better performance than lean $NO_x$ trap (LNT) system to control on-road $NO_x$ emissions. Implementing RDE-LDV will require vehicle manufacturers to adopt the more effective $NO_x$ reduction technology in real driving conditions.

• Journal of Environmental Health Sciences
• /
• v.45 no.5
• /
• pp.474-486
• /
• 2019

Objectives: This study was performed to investigate the emission characteristics of aldehydes emitted by the printing industry and to evaluate their impact on adjacent residential areas. Methods: Aldehydes and THC were measured from the front of the control device in the printing and coating process. Aldehydes and ketones were measured by workplace area, residential area, and background area to evaluate their impact. Results: The concentrations of formaldehyde (<0.047 ppm) and acetaldehyde (<0.068 ppm) in the printing and coating process were relatively low, and the methyl ethyl ketone used as the primary solvent was the main carbonyl compound in the printing process. The daily mean concentrations of formaldehyde and acetaldehyde were not significantly different by workplace area, residential area, or background area. However, the concentration of methyl ethyl ketone was high in the order of workplace area, residential area, and background area. Conclusions: The concentrations of formaldehyde and acetaldehyde in the adjacent residential areas are considered to be more influenced by secondary sources of photochemical reactions than by primary sources. Methyl ethyl ketone is considered to be highly influenced by the primary source, which is printing facilities.

• Journal of Environmental Health Sciences
• /
• v.30 no.3
• /
• pp.293-299
• /
• 2004

Traffic represents one of the largest sources of primary air pollutants in urban area. As a consequence, numerous abatement strategies are being pursued to decrease the ambient concentration of pollutants. A characteristics of most of the these strategies is a requirement for accurate data on both the quantity and spatial distribution of emissions to air in the form of an atmospheric emission inventory database. In the case of traffic pollution, such an inventory must be compiled using activity statistics and emission factors for vehicle types. The majority of inventories are compiled using passive data from either surveys or transportation models and by their very nature tend to be out-of-date by the time they are compiled. The study of current trends is towards integrating urban traffic control systems and assessments of the environmental effects of motor vehicles. In this study, a model of vehicle emission calculation by using real-time traffic data was studied. Traffic data, which are required on a street-by-street basis, is obtained from induction loops of traffic control system. It is possible that characteristics of hourly air pollutants emission rates is obtained from hourly traffic volume and speed. An emission rates model is allocated with a high resolution space by using geographic information system (GIS). Vehicle emission model was developed with a high resolution spatial, gridded and hourly emission rates.

• Journal of Environmental Science International
• /
• v.5 no.6
• /
• pp.699-712
• /
• 1996

For the efficient control of atmospheric quality, it is so important to predict the influence accurately of which the air pollutant emitted into the atmosphere. Atmospheric dispersion model enables to simulate and grasp the atmospheric condition occurred due to the emission of pollutants. The result of model is largely affected by the amount of emission, the characteristics of physical and chemical process, meteorological input data, and the receptor which the concentration is calculated. The aim of this research, therefore, is to suggest more suitable model in Pusan area than other areas by performing TCM2, CDM2.0 and ISCLT2 models. As the basic work for executing the model, we computed the amount of emission of air pollutants in Pusan at 1992 and analyzed the occurrence frequency of atmospheric stability for recent decade(1985~19941, CDM2.0 showed the similar result relatively with observed value in the case of full year(1992), fall and winter, and ISCLT2 brought more suitable result in spring for Pusan area. As the result of this research, in future, it is necessary for us to develop the numerical model considering the topographical characteristics, to select the proper observation site and to increase the observation site for Pusan.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.5
• /
• pp.269-278
• /
• 2016

In order to improve air quality in the Seoul Metropolitan Area (SMA), the "Special Act on Seoul Metropolitan Air Quality Improvement" has been enforced since 2005. The strategy has resulted in some reduction of air pollution, but there has not been much research into the quantitative impact analysis of each separate preventive countermeasure. Therefore, we analyzed nitrogen oxide reduction resulting from implementation of the emission control plan for on-road mobile sources. The MM5-SMOKE-CMAQ model system was employed for air quality prediction. Reduced $NO_x$ emissions for SMA was 16,561 ton, 4.7% of reduction rate, in 2007. One countermeasure, tighter acceptable standards for manufacturing vehicles, dominated other countermeasures for effective $NO_x$ emission control. Large spatial differences in reduced emissions, those for Seoul being twice that of Incheon and Gyeonggi, showed greater $NO_x$ emission reduction impact in the heart of the metropolitan complex. The $NO_2$ concentration decreased by 0.60 ppb (2.0%), 0.18 ppb (1.5%), and 0.22 ppb (1.7%) in Seoul, Incheon, and Gyeonggi, respectively. Concentration decreases in spring and winter were larger, 1.5~2.0 times, than summer and fall. However, the $NO_2$ reduction impact did not correspond directly to local $NO_x$ emission controls in the city area because of the natural flow and dispersion, both urban and downwind.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.6
• /
• pp.772-790
• /
• 2011

In this paper, we use the HDDM (High-order Decoupled Direct Method)-driven ozone sensitivity to predict change in ozone concentrations in response to domain-wide $NO_x$(Oxides of Nitrogen) and VOC (Volatile Organic Compound) emission controls over the Seoul Metropolitan Area during June 11~19, 2007. In order to validate the applicability of HDDM to $NO_x$ and VOC control scenarios, the HDDM results are compared to Brute Force Method (BFM). For VOC controls, NME (Normalized Mean Error) between BFM and HDDM remains less than 2% until the domain-wide VOC emissions are reduced by 80%. The NME for a 40% reduction in the domain-wide $NO_x$ emissions is less than 5% but increases abruptly after further reductions in the $NO_x$ emissions (i.e., 80% reduction). The results indicates that it may be inaccurate to use ozone sensitivity coefficients estimated at a given base emission condition in predicting ozone after $NO_x$ reductions larger than ~50% of the domain total in the SMA. Therefore, HDDM application on piecewise emissions is desirable to predict ozone response to emission controls with accuracy (i.e., truck emissions rather than the domain total). For computational efficiency, HDDM shows approximately 30% faster than the BFM sensitivity approach.

• Journal of Environmental Science International
• /
• v.16 no.3
• /
• pp.299-310
• /
• 2007

It will be necessary to make proper management plans to preserve the air quality in good level for the public. In order to make these plans, source information and detail emission inventories of the city and near industrial areas should be given. However, lack of the source measurements data makes us more difficult to complete the source inventory. VOC source Inventory could be utilized for the feasibility study to estimate the contribution of VOC sources presenting to the receptor such as residential area. It may give policy maker an idea how to control the air quality, and improve their social environment in the area. This study shows data that measured VOCs concentrations from the local industrial areas in Jeonju during from May 2005 to January 2006. The samples were collected from the near sources in 7 major factories in the industrial park as well as 5 general sources in near city Jeonju area to elucidate the abundances of speciated VOCs and their spacial and temporal distributions depending on source bases. Industrial sources are as follows; chemical, food, paper, wood, metal, non-metal (glass), and painting (coating) industries. The 5 general sources are sampled from tunnel, gasoline gas station, dry cleaning shop, printing (copy) shop, and road pavement working place in urban area. To understand the near source effect at receptor, samples from the 2 receptor sites (one is at center of the industrial complex and the other site is at distance residential area downwind from the center) were collected and analyzed for the comparison to source concentration. The mass contributions of the speciated VOC to total mass of VOCs measured from the different sources and ambient (2 receptors) were presented and discussed.