Particulate organic compounds emitted from motor vehicle exhaust and in the urban atmosphere

Matthew P. Fraser, Glen R. Cass, Bernd R.T. Simoneit

Research output: Contribution to journalConference articlepeer-review

131 Scopus citations


The emission rate of particle-phase petroleum biomarkers in vehicular exhaust compared to the concentrations of these biomarkers in ambient air is used to determine the particulate organic compound concentration due to primary particle emissions from motor vehicles in the southern California atmosphere. A material balance on the organic particulate matter emitted from motor vehicle traffic in a Los Angeles highway tunnel first is constructed to show the proportion which is solvent-extractable and which will elute from a GC column, the ratio of resolved to unresolved compound mass, the portion of the resolved material that can be identified as single organic compounds, and the contribution of different classes of organic compounds to the overall identified fraction. It is shown that the outdoor ambient concentrations of the petroleum biomarkers track primary emissions measured in the highway tunnel, confirming that direct emissions of these compounds from vehicles govern the observed ambient petroleum biomarker concentrations. Using organic chemical tracer techniques, the portion of fine organic particulate matter in the Los Angeles atmosphere which is attributable to direct particle emissions from vehicle exhaust is calculated to vary from 7.5 to 18.3% at different sites throughout the air basin during a summertime severe photochemical smog episode. A similar level of variation in the contribution of primary motor vehicle exhaust to fine particulate organic matter concentrations during different times of day is seen. While peak atmospheric concentrations of fine particulate organic carbon are observed during the 1200-1600 PDT afternoon sampling period, only 6.3% of that material is apportioned to the directly emitted particles from vehicle exhaust. During the morning traffic peak between 0600-1000 PDT, 19.1% of the fine particulate organic material is traced to primary emissions from motor vehicles.

Original languageEnglish (US)
Pages (from-to)2715-2724
Number of pages10
JournalAtmospheric Environment
Issue number17
StatePublished - Aug 1999
Externally publishedYes
EventProceedings of the 1997 6th International Conference on Carbonaceous Particles in the Atmosphere - Vienna, Austria
Duration: Sep 22 1997Sep 24 1997


  • Motor vehicle emissions
  • Organic particulate matter
  • Petroleum biomarkers

ASJC Scopus subject areas

  • Environmental Science(all)
  • Atmospheric Science


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