Polycyclic aromatic hydrocarbons in air of Harbin City

Air samples were collected using an improved high volume active air sampler in May 7 to 20, 2008 in Harbin City. Concentrations of polycyclic aromatic hydrocarbons (PAHs) in both gas and particle phases were measured. Total PAHs concentration ranged from 8.1 to 37.2 ng/m³, with an average of 18.2 ng/m³ for all samples. Sources of PAHs were identified by diagnostic ratios of some individual PAHs, which indicated that the dominant source in Harbin was coal combustion. Lower ring PAHs dominated in the gas phase, while the major higher ring PAHs were adsorbed on particle phase. While good correlation was found between gas-particle partition coefficients of PAHs and the respective sub-cooled vapor pressures, non-equilibrium between gas and particle phases was obtained possibly due to the new produced PAHs from coal combustion in winter.