Lipfert F W, Wyzga R E
Electric Power Research Institute, Palo Alto, California, USA.
J Air Waste Manag Assoc. 1997 Apr;47(4):517-23. doi: 10.1080/10473289.1997.10464417.
In a previous paper, we showed that the mean effects on daily mortality associated with air pollution are essentially the same for gases and particulate matter (PM) and are invariant with respect to particle size and composition, based on 27 statistical studies that had been published at that time. Since then, a new analysis reported stronger mortality associations for the fine fractions of PM obtained from dichotomous samplers, relative to the coarse fractions. In this paper, we show that differential measurement errors known to be present in dichotomous sampler data preclude reliable determination of such statistical relationships by particle size. Further, it is necessary to consider gaseous pollutants simultaneously with particles to provide robust estimates of the responsibilities for the implied daily mortality gradients. Finally, certain regression model specifications may be sensitive to differences in frequency distribution characteristics according to particle size.
在之前的一篇论文中，基于当时已发表的27项统计研究，我们表明，与空气污染相关的每日死亡率的平均影响对于气体和颗粒物（PM）基本相同，并且相对于粒径和成分是不变的。从那时起，一项新的分析报告称，相对于粗颗粒部分，二分采样器获得的细颗粒部分的PM与死亡率的关联更强。在本文中，我们表明，二分采样器数据中已知存在的差异测量误差妨碍了通过粒径可靠地确定此类统计关系。此外，有必要同时考虑气态污染物和颗粒物，以便对隐含的每日死亡率梯度的成因提供可靠的估计。最后，某些回归模型规范可能对根据粒径的频率分布特征差异敏感。
