• 关键词：多环芳烃  气固两相  大气  来源解析  健康风险评价

• 基金项目：陕西自然科学基金项目(No.2007D20); 陕西省教育厅专项科研基金项目(No.06JK268); 宝鸡文理学院院级重点项目(No.ZK0797)

• 周变红
• 1. 西安建筑科技大学环境与市政工程学院,西安 710055;
  2. 宝鸡文理学院地理科学与环境工程系,宝鸡 721013

• 张承中
• 西安建筑科技大学环境与市政工程学院,西安 710055

• 王格慧
• 中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室,西安 710075

• 摘要：利用大流量主动采样器于2008年8月至2009年7月采集了西安城区大气样品,研究了大气中多环芳烃(PAHs)的季节变化特征.结果表明,西安大气中16种美国EPA优控的PAHs(∑PAHs)气固两相总浓度为37~620 ng·m^-3(年平均为195 ng·m^-3),具有明显的季节差异,依次为夏季(74 ng·m^-3)＜春季(106 ng·m^-3)＜秋季(213 ng·m^-3)＜冬季(360 ng·m^-3).气态PAHs以3~4环为主,颗粒态PAHs以5~6环为主.分子组成表明西安大气PAHs主要来自于燃煤和机动车尾气及生物质燃烧的复合源.应用BaP毒性当量因子及健康风险评价模型对西安城区成人和儿童进行PAHs健康风险评价,结果显示成人和儿童的日均暴露剂量分别为24.3×10^-6 mg·kg^-1·d^-1和5.6×10^-6 mg·kg^-1·d^-1,终身致癌超额危险度分别为7.5×10^-5和1.7×10^-5,可能造成成人和儿童的预期寿命损失分别约为467.6 min和107.5 min.

• Abstract：Gaseous samples and total suspended particles (TSP) in the atmosphere of Xi'an city were collected from August 2008 to July 2009. The sixteen U.S. EPA priority PAHs were characterized to investigate their seasonal variation in concentration and composition. Human health risk caused by the PAHs was also assessed. The results showed that total concentration of the sixteen PAHs (∑PAHs) in the urban air ranged from 37 to 620 ng·m^-3 with an average of 195 ng·m^-3 during the sampling period. The highest concentration of PAHs was found in winter (360 ng·m^-3 in average), followed by autumn (213 ng·m^-3), spring (106 ng·m^-3) and summer (74 ng·m^-3). Molecular compositions indicated that the gaseous PAHs were mainly composed of 3~4 rings congeners, while the particulate PAHs were largely composed of 5~6 rings. Diagnostic ratios of the PAHs revealed that coal burning, motor vehicle exhaust and biomas burning emission were the major sources in the city. Health risk assessment of PAHs for adults and children in Xi'an was conducted by means of the health risk assessment model and benzo(a)pyrene (BaP)-toxic equivalent factor. The results showed that average daily exposure dose was 24.3×10^-6 mg·kg^-1·d^-1 and 5.6×10^-6 mg·kg^-1·d^-1 for adults and children, respectively. The excess risks for lifelong carcinogenic disease of adults and children were separately 7.5×10^-5 and 1.7×10^-5, possibly exceeding the acceptable levels. The expected loss of lifetime caused by the PAHs would be 467.6 and 107.5 min for adults and children, respectively.

• Key words：PAHs  gas -and particle-phase  atmosphere  source identification  health risk assessment

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