珠江三角洲大气细颗粒物的致癌风险及源解析

于2004年4、7、10月和2005年1月对广州、深圳大气细颗粒物(PM2.5)中17种多环芳烃(PAHs)的浓度进行了分析,以苯并a]芘(BaP)为毒性参照物的致癌毒性当量浓度(BaPeq),通过线性剂量-反应模型计算了呼吸致癌风险水平,结合源排放谱和化学质量平衡受体模型(CMB),研究了对致癌风险的各排放源贡献.结果表明,PAHs的浓度为5.87~63.36ng/m3,平均浓度深圳为32.68 ng/m3,广州为28.15ng/m3,且呈冬高夏低的分布规律.BaP和BaPeq日均超标率达到2.78%和5.56%,相对于WHO的日均标准的超标率达到50.0%和61.1%.该地区呼吸致癌风险平均水平为1×10-6~1×10-5,高于日常活动所致风险,低于引起关注的最低风险值.共解析出3种OC及致癌风险的排放源,分别为燃煤排放、机动车排放、生物质燃烧,其中燃煤排放和生物质燃烧贡献最大,对OC及BaPeq的贡献呈现相似规律.

Cancer risk level and source apportionment of ambient fine particulate matter in Pearl River Delta

Ambient fine paniculate matter (PM_(2.5) in Guangzhou and Shenzhen were collected and analyzed during days in April, July, October 2004 and January 2005, and 17 PAHs concentrations and the toxicity equivalence concentrations (BaP_(eq)) using benzo a] pyrene (BaP) as the primary representative of their toxicity were characterized; inhalation cancer risk levels were calculated through linear dose-response model, and then, the sources of cancer risks were studied using Pearl River Delta (PRD) source profile and CMB receptor model. PAHs concentration were 5.87~63.36ng/m~3, with the average 28.15ng/m~3 in Guangzhou, and 32.68ng/m~3 in Shenzhen ambient air, while it was higher in winter and lower in summer; 2.78% and 5.56% samples exceeded GB3095-1996 daily average standard, respectively; and 50% and 61.1% samples exceeded WHO daily average standard. Average inhalation cancer risk level in PRD area was in the range of 1×10~6~1×10~5, which was higher than risks from everyday life, but lower than minimum level for notification. Besides, 3 sources of inhalation cancer risk were apportioned from CMB model, which were coal burning, vehicle emission and biomass burning, among which coal burning made the largest contribution, and biomass burning was much higher in autumn and winter than in spring and summer. The contributions to both OC and Ba_(Pa), were very similar.