Jaehyun Lim, Cheolsoo Lim, Sungwoon Jung This email address is being protected from spambots. You need JavaScript enabled to view it. 

Division of Global Environment Research, Department of Climate and Air Quality Research, National Institute of Environmental Research, Incheon 22689, Korea

Received: June 28, 2020
Revised: October 20, 2020
Accepted: November 29, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.200356  

Cite this article:

Lim, J., Lim, C., Jung, S. (2021). Characterizations of Size-segregated Ultrafine Particles in Diesel Exhaust. Aerosol Air Qual. Res. 21, 200356. https://doi.org/10.4209/aaqr.200356


  • A medium-duty diesel engine dynamometer with the 13-mode were investigated.
  • Organic compounds (76.6%) including alkanes (67.0%) were emitted in the range of 170–1000 nm.
  • Among all PAHs in the DEPs (< 1 µm), the concentration of phenanthrene was the highest.
  • Two TEQ peaks were identified in the size range of 34–66 nm and 170–330 nm.


Size-segregated ultrafine particles (UFPs) in diesel exhaust were investigated to characterize carbonaceous substances, metals, and organic compounds originating from a medium-duty diesel engine dynamometer using the 13 driving mode. Organic carbon (OC) and elemental carbon (EC) peaked at 330–550 nm, but the OC/EC ratio showed two peaks in the ultrafine and accumulation modes. The distribution trend of metal elements was opposite to that of the size-segregated OC/EC ratio. The amounts of toxic Pb, As, and Cd were less than 0.03–2.5% in diesel exhaust particles (DEPs), but their cumulative fractions in the ultrafine mode exceeded 50%. Most organic compounds (76.6%) and alkanes (67.0%) were emitted in the accumulation mode (170–1000 nm). More than 70% of the identified polycyclic aromatic hydrocarbons (PAHs) were emitted in the accumulation mode (94–1000 nm), with phenanthrene being the most abundant. Two significant size ranges of toxicity equivalent quantity peaks in the ultrafine (34–66 nm) and accumulation (170–330 nm) modes were observed for the size-segregated DEPs. Contrary to the trends for PAHs and organic compounds, the identifiable nitrogen-containing polycyclic aromatic compounds were more abundant in the ultrafine mode. Overall toxicity was high as UFPs can be deposited with high efficiency throughout the human respiratory tract.

Keywords: Diesel exhaust particles, Organic carbon, Elemental carbon, Metal elements, Polycyclic aromatic hydrocarbons, Nitrogen-containing polycyclic aromatic compounds, Toxicity

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