Duan Jingchun, Bi Xinhui, Tan Jihua, Sheng Guoying, Fu Jiamo
State Key Laboratory of Organic Geochemistry, Guangzhou Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Chemosphere. 2007 Mar;67(3):614-22. doi: 10.1016/j.chemosphere.2006.08.030. Epub 2006 Dec 12.
Size distribution aerosol samples were collected at an urban location of Guangzhou in four seasons of 2003-2004 by a MOUDI (Micro-orifice Uniform Deposit Impactor). The particle loading (PM10: 80-397 microg m(-3)) was comparable with some other Asia cities; however, much higher than that of Western Europe and North America. Polycyclic aromatic hydrocarbons (PAHs) were measured by gas chromatography with mass selective detector (GC-MS). Seasonal effects on the size distribution of PAHs are presented. Bimode (accumulation and coarse mode) and unimode (accumulation mode) distributions were observed for low-molecule-weight and high-molecule-weight PAHs. A slight shift to larger particles was found for the accumulation mode in autumn and winter, compared with that of spring and summer. One explanation is that the longer aging process of PAHs in autumn and winter would result in volatilization from finer particles followed by condensation onto coarser particles. Another is there was mixing process of local emission with long-range transported aerosol in autumn and winter. The relative higher value of IcdP/(BghiP+IcdP) and lower value of BghiP/BeP in winter also give evidences to the mixing process. The level of PAHs concentration has been much elevated in recent years. This can be attributed to the fast growth of motor vehicle and energy consumption.
2003年至2004年四季期间，在广州的一个城市地点使用微孔均匀沉积冲击器（MOUDI）收集了气溶胶样本的粒径分布。颗粒物负荷（PM10：80 - 397微克/立方米）与其他一些亚洲城市相当；然而，远高于西欧和北美的水平。采用带质量选择检测器的气相色谱法（GC - MS）测定多环芳烃（PAHs）。给出了多环芳烃粒径分布的季节效应。观察到低分子量和高分子量多环芳烃呈现双峰（积聚和粗模态）和单峰（积聚模态）分布。与春季和夏季相比，秋冬季节积聚模态向较大颗粒有轻微偏移。一种解释是，秋冬季节多环芳烃较长的老化过程会导致其从较细颗粒挥发，随后凝结在较粗颗粒上。另一种解释是，秋冬季节存在本地排放与长距离传输气溶胶的混合过程。冬季IcdP/（BghiP + IcdP）的相对较高值和BghiP/BeP的较低值也为混合过程提供了证据。近年来多环芳烃浓度水平大幅升高。这可归因于机动车和能源消耗的快速增长。
