Sungwoon Jung1, Sunhee Mun1, Taekho Chung1, Sunmoon Kim1, Seokjun Seo1, Ingu Kim1, Heekyoung Hong 1, Hwansoo Chong1, Kijae Sung2, Jounghwa Kim1, Youdeog Hong1

Transportation Pollution Research Center, National Institute of Environmental Research, Incheon 22689, Korea
HORIBA Korea Ltd., Seoul 06259, Korea

Received: June 25, 2018
Revised: October 10, 2018
Accepted: October 11, 2018
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Cite this article:
Jung, S., Mun, S., Chung, T., Kim, S., Seo, S., Kim, I., Hong, H., Chong, H., Sung, K., Kim, J. and Hong, Y. (2019). Emission Characteristics of Regulated and Unregulated Air Pollutants from Heavy Duty Diesel Trucks and Buses. Aerosol Air Qual. Res. 19: 431-442.


  • Heavy-duty diesel trucks and buses emitted regulated and unregulated pollutants.
  • Reduction for regulated emissions was affected by engine start conditions.
  • Alkanes emissions were higher than those of alkenes, cycloalkanes, and aromatics.
  • Formaldehyde was the major NMHC component, and PAHs were hardly detected.
  • Low exhaust gas temperature during urban driving cycle causes heavy air pollution.


Due to the common stop-and-go driving style, the low temperature of vehicular exhaust gas in the urban driving cycle is a major cause of air pollution in the Seoul Metropolitan Area. We herein investigate the characteristics of regulated (NOx, PM, CO, and non-methane hydrocarbons (NMHC)) and unregulated (volatile organic compounds (VOCs), aldehydes, and polycyclic aromatic hydrocarbons (PAHs)) air pollutants emitted from heavy duty diesel trucks and buses equipped with different after-treatment systems (diesel particulate filter (DPF) + exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) in urban conditions. NOx emissions depended on the combustion and working temperature of the SCR catalysts, and PM emissions were low. Alkanes dominated the non-methane volatile organic compound (NMVOC) emissions, 43–59% of which resulted from the low efficiency of the oxidation catalyst for alkane. The after-treatment system and the engine start conditions influenced the chemical components of the NMVOC emissions due to incomplete combustion and the evaporation of liquid fuel. Formaldehyde comprised the largest portion of the aldehydes, whereas PAH emissions remained largely undetected. Furthermore, formaldehyde was the largest contributor to the NMHCs, forming 14–29%. The results of this study will aid in establishing a system for calculating hazardous air pollutants emitted by vehicles in Korea.

Keywords: Volatile organic compounds; Aldehydes; Polycyclic aromatic hydrocarbons; Heavy duty diesel trucks and buses; After-treatment systems.


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