Dry Deposition of Airborne Particles and Characteristics of Polycyclic Aromatic Hydrocarbons in Urban Kaohsiung, Taiwan

The concentrations of twenty-one individual polycyclic aromatic hydrocarbons (PAHs) and total suspended particles (TSP) were measured using high-volume air samplers at two sites (Tzuo-Yin and Hsiung-Kong) in Kaohsiung City, Taiwan for during four seasons from 2005 to 2006. The gaseous and particulate phases of individual PAHs were identified using a gas chromatograph with a flame-ionization detector (GC/FID). The deposition fluxes of airborne particles at the two sites were measured with dry deposition plates. The results show that the concentrations of total (gas + particulate) PAHs generally followed the seasonal variations of the concentrations of TSP (107.18-117.09 mu g/m super(3)), being the highest in winter (143.9-182.9 ng/m super(3)) and lowest in summer (81.4-95.2 ng/m super(3)) at both sites. The differences in the results at the two sites are mainly attributed to the different industries at each site. The mean deposition fluxes of airborne particles were between 182.2 and 195.3 mg/m super(2)-day, with a dry deposition velocity of 2.00-2.04 cm/s. Most PAH species were low-weight PAHs (approximately 80.8-82.0%), followed by high-weight PAHs (10.5-14.6%) and medium-weight PAHs (6.5-6.8%). The fractions of gaseous PAHs decreased with molecular weight or ring number. The particle phase (60.2-73.5%) dominated the high-weight PAHs.