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Typical and Atypical Morphology of Non-volatile Particles from a Diesel and Natural Gas Marine Engine

Category: Aerosol and Atmospheric Chemistry

Volume: 20 | Issue: 4 | Pages: 730-740
DOI: 10.4209/aaqr.2020.01.0006
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To cite this article:
Baldelli, A., Trivanovic, U., Corbin, J.C., Lobo, P., Gagné, S., Miller, J.W., Kirchen, P. and Rogak, S. (2020). Typical and Atypical Morphology of Non-volatile Particles from a Diesel and Natural Gas Marine Engine. Aerosol Air Qual. Res. 20: 730-740. doi: 10.4209/aaqr.2020.01.0006.

Alberto Baldelli 1, Una Trivanovic1, Joel C. Corbin2, Prem Lobo2, Stephanie Gagné2, J. Wayne Miller3, Patrick Kirchen1, Steven Rogak1

  • 1 Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
  • 2 Metrology Research Centre, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
  • 3 Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA


  • Higher engine loads generate larger aggregates and larger primary particle sizes.
  • Atypical particles are non-uniform primaries, super-aggregates, and compact.
  • Non-uniform primaries are 40 and 15% in diesel and NG exhaust respectively.
  • Particles not composed of soot are spheres, mineral-like, and fibers.
  • Spheres and fibers are found only in diesel and NG emissions respectively.


Non-volatile particle emissions from a marine engine fueled by either diesel or natural gas (NG) blended with diesel pilot gas were investigated via transmission electron microscopy (TEM). The most common particles (> 95% by number) were soot aggregates. These “typical” aggregates exhibited primary particle diameters of 20.7 ± 1.9 and 26.9 ± 1.7 for 100 nm aggregates when diesel and NG fuel were used, respectively. Highly non-uniform aggregates, with distinct groups of smaller and larger monomers, were visible in all of the samples but occurred most frequently with diesel fueling at high loads. The observed “atypical” particles included super-aggregates, small compact aggregates, spheres, mineral-like polyhedral particles, and fibers. Such particles, although rare (averaging 3% by number, as calculated by counting the number of particles for each type depicted in all of the collected images), were found in most of the samples and could have been produced by a variety of mechanisms. For instance, the spheres (approximately 300 nm in diameter) most likely arose from metals within the lubricating oil.


Natural gas Diesel Transmission electron microscope Primary particle diameter Projected-area-equivalent diameter Marine exhaust

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DOI: 10.4209/aaqr.2019.12.0658