Particle size distribution of polycyclic aromatic hydrocarbons in motorcycle exhaust emissions.
The size distribution of polycyclic aromatic hydrocarbons (PAHs) in emission of a two-stroke carburetor motorcycle was studied. The exhaust gas from the test motorcycle was passed to a dilution tunnel and collected using a 10 cascade micro-orifice uniform deposit impactor (MOUDI) of 0.056-10 microm aerodynamic diameter fitted with aluminum substrates. All MOUDI substrates were analyzed for particulate mass and for PAHs by GC/MS. Most of the 21 analyzed PAHs have two significant modes that peak at <0.1 and 0.18-0.32 microm. For some PAHs, a third peak appears around 1.8 microm. MOUDI impactor samples show that 88.9% particulate and 89.6% PAH mass distributed smaller than 2.5 microm. Mass median diameters of PAHs are about 0.2 microm. Total benzo[a]pyrene toxic equivalency emission factor was 440+/-13.8 ng/km for the test motorcycle. An average of 90.3% of carcinogenicity is observed in particulate smaller than 1.0 microm. The results suggest that submicron particulates predominate in the exhaust from motorcycle and exhibit high carcinogenic potency for these particulate.
Yang
Hsi-Hsien
HH
Department of Environmental Engineering and Management, Chaoyang University of Technology, Wufong, Taichung 41349, Taiwan. hhyang@mail.cyut.edu.tw
Chien
Shu-Mei
SM
Chao
Mu-Rong
MR
Lin
Chi-Chwen
CC
D000393:Air Pollutants / Q000032:analysis; D002274:Carcinogens, Environmental / Q000032:analysis; D009049:Motorcycles; D010316:Particle Size; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*
D000393:Air Pollutants; D002274:Carcinogens, Environmental; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions