No abstract

The most prevalent pollutant, polycyclic aromatic hydrocarbons (PAHs) is now plenteously distributed in the global atmosphere. We recently quantified 36 polycyclic aromatic hydrocarbons (PAHs) associated with aerosols (particulate matter: PM) in five Asian cities: Tokyo (Japan), Beijing (China), Kolkata (India), Hanoi (Vietnam), and Kuala Lumpur (Malaysia). Average atmospheric PAH concentrations (∑12 PAHs-ng m -3 ) increased in the order of Kuala Lumpur (2.99) ≈ Tokyo (3.95) < Hanoi (7.99) << Kolkata (63.5) << Beijing (142.8). The most abundant PAHs in PM samples in these cities were chrysene, benz [a]anthracene, benzofluoranthenes, benzo[a]pyrene, and benzo[e]pyrene. We used the PAH compositions, especially the relative abundances of alkylated PAHs, and hopanes to determine vehicle exhaust-derived PAHs, and levoglucosan as a tracer for biomass burning, especially from wood combustion. Vehicle exhaust contributed to atmospheric PAHs in all cities, indicated by higher ratios of (C 30 17α)/total PAHs and MPAHs/PAHs than coal and wood combustion products. Coal combustion contributed also in winter aerosols in Beijing, indicated by higher abundance of β isomers i.e., 17β21β (H)-C 30 hopane (C 30 17β) and 17β21β (H)-C 29 hopane (C 29 17β) signifying mass use of coal for heating. The ratio of levoglucosan/PAHs was high in Kuala Lumpur and Hanoi, suggesting greater inputs of PAHs from biomass burning there.