PMB 2.5 B aerosols were collected in Nanjing, a typical mega-city in China, during 1 summer and winter 2004 and were characterized for aromatic and cyclic compounds using a 2 GC/MS technique to understand the air pollution problem. They include polycyclic aromatic 3 hydrocarbons (PAHs), hopanes, phthalates and hydroxy-PAHs (OH-PAHs). PAHs, hopanes and 4 OH-PAHs presented higher concentrations in winter 3 due to an enhanced evaporation from 9 plastics during the hot season and the subsequent deposition on the pre-existing particles. 10Generally, all the identified compounds are more abundant in nighttime than in daytime due to 11 inversion layers and increased emissions from heavy-duty trucks at night. PAHs, hopanes and 12 phthalates in Nanjing aerosols are 5−100 times more abundant than those in Los Angeles, USA, 13 indicating a serious air pollution problem in the city. Concentrations of OH-PAHs are 1−3 orders 14 of magnitude less than their parent PAHs and comparable to those reported from other 15 international cities. Source identification using diagnostic ratios of the organic tracers suggests 16 that PAHs in Nanjing urban area are mainly derived from coal burning, whereas hopanes are 17 more attributable to traffic emissions. 18

No abstract

No abstract