• Journal of Korean Society of Transportation
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• v.33 no.5
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• pp.449-460
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• 2015

The reliability of air quality evaluation results for green transportation could be improved by applying correct emission factors. Unlike previous studies, which estimated emission factors that focused on vehicles in laboratory experiments, this study investigates emission factors according to road types and time using real driving data. The real driving data was collected using a Portable Activity Monitoring System (PAMS) according to road types and time, which it compared and analyzed fuel consumption from collected data. The result of the study shows that fuel consumption on national highway is 17.33% higher than the fuel consumption on expressway. In addition, the average fuel consumption of peak time is 4.7% higher than that of non-peak time for 22.5km/h. The difference in fuel consumption for road types and time is verified using ANOCOVA and MANOVA. As a result, the hypothesis of this study - that fuel consumption differs according to road types and time, even if the travel speed is the same - has proved valid. It also suggests correction factor of emission factors by using the difference in fuel consumption. It is highly expected that this study can improve the reliability of emissions from mobile pollution sources.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.805-810
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• 2003

The annual air pollution emissions from construction and agricultural equipments were estimated from 1987 through 2000. The annual numbers and operation hours of 5 major construction equipments (Excavator, Bulldozer, Loader, Fork lift, Crane) and 3 major agricultural equipments (Power Tiller, Agricultural Tractor, Combine) were investigated for emission estimation. And monthly variation factors of operation hours of construction equipment were investigated too. The NO$_{x}$ emission from construction equipment have been gradually increased since 1987 to 1997, but sharply decreased as -45％ in 1998 due to economic crisis in Korea. The NO$_{x}$ emission was estimated as 64,300 ton/year from construction equipment, and as 23,300 ton/year from agricultural equipment in 2000.000.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.467-472
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• 2003

Of those off-road diesel engines, the railroad diesel rolling stocks (RDRS) for passenger and freight transportation become a growing issue since they are emitting enormous amounts of various air pollutants. Furthermore, up to the present time, emissions from these sources are not well controlled. One of main purposes in this study is to develop emission factors for the RDRS and to estimate a total amount of major air pollutants from the RDRS in Korea. Prior to develop a Korean mode emission factor, the emission factor from the USEPA was simply applied for comparative studies. As a conclusion, based on the emissions calculated from both the USEPA mode and the KoRail mode, the RDRS is considered as one of significant mobile sources of major air pollutants including NOx and CO, and thus management plans and control strategies for the RDRS must be established to improve air quality near. future in Korea.

• Particle and aerosol research
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• v.7 no.1
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• pp.21-30
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• 2011

The spatial distributions of air pollutants, in particular, ultrafine particles near traffic congestion roads at urban areas need to reduce human exposure levels for protecting public health. In this study, the number concentrations of ultrafine particles larger than 5 nm were measured every second during driving on the major roads of Nowon-gu, Seoul for 1.6 h using a mobile emission laboratory on October 5, 2010. The ultrafine particle number concentrations ranged from 7,009 to $265,600particles/cm^3$ with an average of $55,570particles/cm^3$, and these levels were comparable to concentrations of ultrafine particles larger than 3 or 7 nm on the arterial roads at urban areas in Los Angeles, USA and Zurich, Switzerland. It was frequently observed that the ultrafine particle number increased rapidly when vehicle speed was accelerated and it decreased sharply when vehicle speed was decelerated. The high peak events of ultrafine particle concentration larger than $200,000particles/cm^3$ were observed seven times during the measurement period. From the three repeated measurements during the short period of 50 min, it was concluded that the ultrafine particle number concentration on the road was significantly time-dependent. This on-road measurement approach can be utilized to manage vehicle-related air pollution in urban.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.183-193
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• 2009

Air pollution due to vehicle exhaust gas is considered to be a main contributor to the issues of transportation & environment. Furthermore it is raising concern over life quality and public health and is also perceived as a global issue. This research aims at providing helping hands for both central and local governments to set up and promote efficient atmospheric quality improvement policies, with the help of the travel demand forecasting model and GIS. More specifically, it tries to produce the overall emission level with time and space-based high resolution framework. This research, based on bottom-up approach reflecting vehicular traffic characteristics, suggested an improved approach to estimating emission level, by using a traffic model with a total of vehicular mileage revised by surveyed value and atmosphere model. Summing up, using the method proposed, the improvement of the reliability of the emissions inventory from the mobile pollutions sources is expected by the proposed integrated paradigm of transportation and atmosphere modeling approach as a new alternative.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.92-99
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• 2011

To measure the traffic pollutants with high temporal and spatial resolution under real conditions, a mobile emission laboratory (MEL) was designed. The equipment of the mini-van provides gas phase measurements of CO, NOx, $CO_2$, THC (Total hydrocarbon) and number density & size distribution measurements of fine and ultra-fine particles by a fast mobility particle sizer (FMPS) and a condensation particle counter (CPC). The inlet sampling port above the bumper enables the chasing of different type of vehicles. This paper introduces the technical details of the MEL and presents data from the car chasing experiment of diesel bus equipped with aftertreatment system. The dilution ratio was calculated by the ratio of ambient NOx and tail-pipe NOx. Most particles from the diesel bus were counted under 300 nm and the peak concentration of the particles was located between 30 and 60 nm. The total PM number emission from diesel bus equipped with DPF was 10 orders of magnitude lower compared to those emitted from base diesel bus. And the total PM number emission from diesel bus equipped with SCR was comparable to the particle emission from base diesel bus.

• Journal of Urban Science
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• v.11 no.2
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• pp.45-54
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• 2022

Recently, regulations on automobile exhaust gas emission are being strengthened. Accordingly, automobile exhaust gas emissions are expected to decrease and continue to decrease. On the other hand, many countries do not yet consider the emission of non-exhaust air pollutants from automobiles as important. Automobile non-exhaust substances are classified into three categories: tire dust emissions, brake wear emissions, and road scattering dust. In particular, in the case of tire dust, research results exist that pollutant emissions increase as the weight of a vehicle increases. Since the weight of trucks varies according to the load and the load along the axles is also different, it can be expected that the emission of PM10 from the tire dust will be different depending on the loading method. Therefore, this study was conducted on the amount of PM10 generated in tire dust considering the axle load of the truck according to the loading method. However, it was confirmed that the total amount of PM10 was less than that all loads are loaded in the front or rear when the load was evenly distributed in the front and rear of the cargo compartment. In particular, if the load is distributed evenly in the front and back of the cargo compartment and the load in the front part is divided into 2 to 6 and loaded, as the number of divided loading increases the amount of PM10 generated decreases. And when the load is divided into 6 pieces, the total amount of PM10 generated is 0.3952g, the minimum value. If the load is divided into 6 or more and loaded evenly, the total PM10 generated continuously increases and converges to about 0.3964g.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.737-744
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• 2012

A mobile emission laboratory (MEL) was designed to measure the amount of traffic pollutants, with high temporal and spatial resolution under real conditions. Equipment for the gas-phase measurements of CO, NOx, $CO_2$, and THC and for the measurement of the number, concentration, and size distribution of fine and ultra-fine particles by an FMPS and CPC was placed in a minivan. The exhausts of different types of vehicles can be sampled by an MEL. This paper describes the technical details of the MEL and presents data from the experiment in which a car chases passenger vehicles fuelled by diesel and gasoline. The particle number concentration in the exhaust of the diesel vehicle was higher than that of the gasoline vehicle. However, the diesel vehicle with a DPF emitted fewer particles than the vehicle equipped with a gasoline direct injection engine, with particle diameters over 50 nm.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.37-49
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• 2017

This study proposes an analysis methodology for air quality improvement effect of transport and environment policy that are used for mobile pollution sources. The methodology considers the changes of traffic of road transport sources and air pollutant emission, the changes of atmospheric dispersion of air pollutants and the effects on the health of local residents in response to policy implementation. Especially, the changes to traffic flow must be considered in evaluating the effects on atmospheric environment as it has a direct connection to the effects of the policy in this study. We used bottom-up approach (BUA) based on the travel demand model to reflect the changes of travel behavior in detail in response to the policy implementation compared to the top-down approach (TDA) when calculating the changes of emission level of road transport. We showed the applicability of the proposed analysis methodology through a policy scenario analysis, and the analysis method can be effectively applied to the cases in which travelers' behavior changes are expected.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.90-101
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• 2009

An objective of this study is to suggest a procedure to evaluate vehicle emissions regardless of the driving pattern. Field experiments using portable emission measurement system were conducted under the real world driving cycle. Standardized average for NOx, $CO_2$ emission and fuel consumption rates were calculated while the vehicle specific power distribution within each vehicle speed bin was taken into consideration. Composite emission factor and fuel economy, which were obtained based on the standardized average results and traffic statistics, showed good similarity to those acquired through the conventional chassis dynamometer tests qualitatively as well as quantitatively. Considering that a conventional method obviously has a limitation to reflect various characteristics of the real world, the new approach suggested in this study can be used as an alternative procedure to collect more specific data to establish the mobile emission factors.