Laden F, Neas L M, Dockery D W, Schwartz J
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Environ Health Perspect. 2000 Oct;108(10):941-7. doi: 10.1289/ehp.00108941.
Previously we reported that fine particle mass (particulate matter [less than and equal to] 2.5 microm; PM(2.5)), which is primarily from combustion sources, but not coarse particle mass, which is primarily from crustal sources, was associated with daily mortality in six eastern U.S. cities (1). In this study, we used the elemental composition of size-fractionated particles to identify several distinct source-related fractions of fine particles and examined the association of these fractions with daily mortality in each of the six cities. Using specific rotation factor analysis for each city, we identified a silicon factor classified as soil and crustal material, a lead factor classified as motor vehicle exhaust, a selenium factor representing coal combustion, and up to two additional factors. We extracted daily counts of deaths from National Center for Health Statistics records and estimated city-specific associations of mortality with each source factor by Poisson regression, adjusting for time trends, weather, and the other source factors. Combined effect estimates were calculated as the inverse variance weighted mean of the city-specific estimates. In the combined analysis, a 10 microg/m(3) increase in PM(2.5) from mobile sources accounted for a 3.4% increase in daily mortality [95% confidence interval (CI), 1.7-5.2%], and the equivalent increase in fine particles from coal combustion sources accounted for a 1.1% increase [CI, 0.3-2.0%). PM(2.5) crustal particles were not associated with daily mortality. These results indicate that combustion particles in the fine fraction from mobile and coal combustion sources, but not fine crustal particles, are associated with increased mortality.
我们之前报道过，主要来自燃烧源的细颗粒物质量（粒径小于等于2.5微米的颗粒物；PM₂.₅），而非主要来自地壳源的粗颗粒物质量，与美国东部六个城市的每日死亡率相关（1）。在本研究中，我们利用粒径分级颗粒物的元素组成来识别细颗粒物中几个不同的与源相关的组分，并研究这些组分与六个城市中每个城市每日死亡率的关联。通过对每个城市进行特定的旋转因子分析，我们识别出一个归类为土壤和地壳物质的硅因子、一个归类为机动车尾气的铅因子、一个代表煤炭燃烧的硒因子，以及多达两个其他因子。我们从美国国家卫生统计中心的记录中提取每日死亡人数，并通过泊松回归估计每个源因子与特定城市死亡率的关联，同时对时间趋势、天气和其他源因子进行调整。合并效应估计值计算为特定城市估计值的逆方差加权平均值。在合并分析中，来自移动源的PM₂.₅每增加10微克/立方米，每日死亡率增加3.4%[95%置信区间（CI），1.7 - 5.2%]，来自煤炭燃烧源的细颗粒物等量增加导致死亡率增加1.1%[CI，0.3 - 2.0%]。PM₂.₅地壳颗粒物与每日死亡率无关。这些结果表明，来自移动源和煤炭燃烧源的细颗粒物中的燃烧颗粒物，而非细地壳颗粒物，与死亡率增加相关。
