Emissions of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) in the Shing Mun Tunnel, Hong Kong

K. F. Ho, Steven Sai Hang Ho, Shuncheng Lee, Y. Cheng, Judith C. Chow, John G. Watson, P. K.K. Louie, Linwei Tian

Research output: Journal article publicationJournal articleAcademic researchpeer-review

137 Citations (Scopus)


Real-world vehicle emission factors for seventeen gas and particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in the Shing Mun Tunnel, Hong Kong during summer and winter 2003. Naphthalene, acenaphthylene, and acenaphthene were the most abundant gas PAHs while fluoranthene and pyrene were the most abundant in the particle phase. Most (98%) of the gas PAHs consisted of two- and three-aromatic rings whereas most of the particle-phase PAHs were in four- (∼60%) and five-ring (∼17%) for fresh exhaust emissions. Average emission factors for the gas- and particle PAHs were 950-2564 μg veh-1 km-1and 22-354 μg veh-1 km-1, respectively. Good correlations were found between diesel markers (fluoranthene and pyrene; 0.85) and gasoline markers (benzo(ghi)perylene and indeno(1,2,3-cd)pyrene; 0.96). Higher PAH emission factors were associated with a higher fraction of diesel-fueled vehicles (DV) passing through the tunnel. Separate emission factors were determined from diesel and non-diesel exhaust by the regression intercept method. The average PAH emission factor (i.e., sum of gas and particle phases) from DV (3085 ± 1058 μg veh-1 km-1) was ∼5 times higher than that from non-diesel-fueled vehicles (NDV, 566 ± 428 μg veh-1 km-1). Ratios of DV to NDV emission factors were high for diesel markers (>24) and low for gasoline markers (<0.4).
Original languageEnglish
Pages (from-to)6343-6351
Number of pages9
JournalAtmospheric Environment
Issue number40
Publication statusPublished - 16 Oct 2009


  • Emission factor
  • Gas- and particle PAHs
  • Hong Kong
  • PAH
  • Tunnel

ASJC Scopus subject areas

  • General Environmental Science
  • Atmospheric Science


Dive into the research topics of 'Emissions of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) in the Shing Mun Tunnel, Hong Kong'. Together they form a unique fingerprint.

Cite this