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[Characteristics and seasonal variations and influence factors on polycyclic aromatic hydrocarbons in Guangzhou city].

Weekly particulate and gas phase polycyclic aromatic hydrocarbons (PAHs) were sampled by a modified high-volume sampler in Guangzhou city from April 2001 to March 2002. The average total gas and particulate concentrations (sigma PAHs) were 312.9 ng/m3 and 23.7 ng/m3, respectively. The predominant PAHs in the air were 2 to approximately 4-ring compounds in vapor phase. Clear seasonal trends were observed, with higher concentration in summer and lower in winter for gas phase PAHs and adversely for particulate phase PAHs. Ambient temperature was predominating factor influencing the variation of gas phase PAHs concentrations and temperature together with wind speed and relative humidity were main meteorological parameters affecting the fluctuations of particle phase PAHs.