Hydrocarbon condensation in heavy-duty diesel exhaust

J. Ristimäki, Kati Vaaraslahti, Maija Lappi, Jorma Keskinen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

47 Citations (Scopus)


The semivolatile mass fraction of diesel exhaust particles was studied using size-resolved on-line techniques (DMA-ELPI; TDMA-ELPI).
The average density of the semivolatile liquid on the particles was measured to be approximately 0.8 g/cm3. The measured size resolved values of mass transfer imply that condensation, or diffusion-limited mass transfer, plays a major role in driving the volatile matter to the diesel exhaust particles.
The measured mass change values correspond to highly size dependent mass fractions for the semivolatile component, ranging from approximately 20−80%. Integrated over particle size distribution, the volatile mass fractions were 25 and 45% for the two load points studied.
Calculation, based on the measured particle properties, indicates that only 10% volatile mass fraction could be explained by monolayer adsorption.
The size resolved changes in particle effective density, fractal dimension, volatile mass fractions and mass are all in agreement with theoretical considerations of condensation.
Original languageEnglish
Pages (from-to)6397-6402
JournalEnvironmental Science & Technology
Issue number18
Publication statusPublished - 2007
MoE publication typeA1 Journal article-refereed


  • diesel
  • diesel engine exhaust
  • diesel exhaust
  • diesel exhaust emission control
  • heavy-duty vehicles


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