Wu Chang-Fu, Wu Szu-Ying, Wu Yi-Hua, Cullen Alison C, Larson Timothy V, Williamson John, Liu L-J Sally
Department of Public Health, National Taiwan University, Taipei, Taiwan.
Environ Int. 2009 Apr;35(3):516-22. doi: 10.1016/j.envint.2008.09.009. Epub 2008 Nov 8.
The risk estimates calculated from the conventional risk assessment method usually are compound specific and provide limited information for source-specific air quality control. We used a risk apportionment approach, which is a combination of receptor modeling and risk assessment, to estimate source-specific lifetime excess cancer risks of selected hazardous air pollutants. We analyzed the speciated PM(2.5) and VOCs data collected at the Beacon Hill in Seattle, WA between 2000 and 2004 with the Multilinear Engine to first quantify source contributions to the mixture of hazardous air pollutants (HAPs) in terms of mass concentrations. The cancer risk from exposure to each source was then calculated as the sum of all available species' cancer risks in the source feature. We also adopted the bootstrapping technique for the uncertainty analysis. The results showed that the overall cancer risk was 6.09 x 10(-5), with the background (1.61 x 10(-5)), diesel (9.82 x 10(-6)) and wood burning (9.45 x 10(-6)) sources being the primary risk sources. The PM(2.5) mass concentration contributed 20% of the total risk. The 5th percentile of the risk estimates of all sources other than marine and soil were higher than 110(-6). It was also found that the diesel and wood burning sources presented similar cancer risks although the diesel exhaust contributed less to the PM(2.5) mass concentration than the wood burning. This highlights the additional value from such a risk apportionment approach that could be utilized for prioritizing control strategies to reduce the highest population health risks from exposure to HAPs.
通过传统风险评估方法计算出的风险估计值通常是针对化合物的，为特定来源的空气质量控制提供的信息有限。我们采用了一种风险分配方法，该方法是受体模型和风险评估的结合，来估计选定有害空气污染物的特定来源终生超额癌症风险。我们使用多线性引擎分析了2000年至2004年期间在华盛顿州西雅图市灯塔山收集的特定种类的PM（2.5）和挥发性有机化合物（VOCs）数据，首先从质量浓度方面量化源对有害空气污染物（HAPs）混合物的贡献。然后将暴露于每个源的癌症风险计算为源特征中所有可用物种癌症风险的总和。我们还采用了自抽样技术进行不确定性分析。结果表明，总体癌症风险为6.09×10^(-5)，背景风险（1.61×10^(-5)）、柴油（9.82×10^(-6)）和木材燃烧（9.45×10^(-6)）源是主要风险源。PM（2.5）质量浓度贡献了总风险中的20%。除海洋和土壤之外的所有源的风险估计值的第5百分位数高于1×10^(-6)。还发现，尽管柴油废气对PM（2.5）质量浓度的贡献低于木材燃烧，但柴油和木材燃烧源呈现出相似的癌症风险。这突出了这种风险分配方法的额外价值，可用于确定控制策略的优先级，以降低因接触HAPs而带来的最高人群健康风险。
