Seasonal Variation of Particulate Polycyclic Aromatic Hydrocarbons Associated with PM_(10) in Guangzhou, China

112 PM_(10)(particulates matter with aerodynamic diameter 10?μm) samples were collected at Liwan and Wushan site in Guangzhou between March 2002 and June 2003. Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed with GC/MS. The results showed that PAHs exhibited the distinct from seasonal variation. The concentration of ∑PAHs ranged from 8.11 to 106.26?ng/m~3. The highest concentration of PAHs in PM_(10) was observed in winter, with the lowest level in summer. 5～6 rings of PAHs were the abundant compounds, which accounted for 65%～90% of ∑PAHs. Significantly seasonal variations were also found in the PAHs contribution pattern. 5～6 ring PAHs had a trend of higher relative contribution in summer, while 3～4 ring PAHs tended to have a higher contribution in winter. The temperature was a possible factor influencing on the PAHs distribution pattern. The PAHs concentration and distribution pattern fluctuated greatly in winter due to cold current. Based on the significant difference of temperature in winter, the samples were classified into two groups and the distribution and the abundance of the PAHs in two groups were significantly different. Meteorological conditions had a strong influence on the seasonal variability. The wind speed (when the temperature was less than or equal to 20℃) and the temperature (when the temperature was bigger than 20℃) were main influencing factors of the PAHs concentration. Furthermore, the diagnostic ratios suggested vehicle emission was the predominant sources for particulate PAHs in Guangzhou.