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[背景]十余年的卫星观测提供了全球细颗粒物(PM2.5)人群暴露趋势和大小的信息。[目的]利用多个卫星的测量值推断的PM2.5浓度,建立和改进大气PM2.5质量和趋势的全球暴露评估。[方法]结合3个卫星反演的PM2.5源数据,得出1998—2012年10 km×10 km尺度上全球PM2.5估计值。对每一个源数据,通过GEOS-Chem化学物运输模型把气溶胶光学厚度总柱反演与近地面PM2.5联系起来,以表示当地的气溶胶光学性能和垂直廓线。从文献中收集210个全球基于地面的PM2.5观测值,用北美和欧洲之外其他地区的测量值来评估基于卫星的估计值。[结果]1998—2012年,全球人口加权的大气PM2.5浓度每年增加0.55μg/m3(95%CI:0.43~0.67)(2.1%/年;95%CI:1.6%~2.6%)。尽管在一些发达地区PM2.5减少,但在一些发展中地区PM2.5的增加推动了这一全球性的变化。在东亚,PM2.5水平高于世界卫生组织(WHO)第一个中期目标35μg/m3的人口比例从1998—2000年的51%上升到2010—2012年的70%。相比之下,北美高于WHO空气质量指南10μg/m3的人口比例,从1998—2000年的62%下降到2010—2012年的19%。北美及欧洲以外地区的卫星反演估计值和地面测量值之间存在关联(r=0.81;n=210;斜率=0.68)。卫星反演的估计值偏低,提示真实的全球浓度可能更高。[结论]卫星观测值提供了大气PM2.5浓度的全球性长期变化的新认识。从这项研究中获得的PM2.5的卫星反演估计值和地面观测值可供公众使用。
Background More than ten years of satellite observations have provided information on the trends and magnitude of exposure to PM2.5 populations worldwide. [Objective] To estimate the global PM2.5 concentration and establish and improve global exposure assessment of atmospheric PM2.5 quality using the measured values of multiple satellites. [Method] Based on the PM2.5 source data retrieved from 3 satellites, the global PM2.5 estimation from 10 km × 10 km from 1998 to 2012 was obtained. For each source data, the total column aerosol optical thickness inversion was correlated with the near-surface PM 2.5 by the GEOS-Chem chemical transport model to represent local aerosol optical properties and vertical profiles. 210 global earth-based PM2.5 observations were collected from the literature and satellite-based estimates were evaluated using measurements from other parts of North America and Europe. [Results] The global population weighted atmospheric PM2.5 concentration increased 0.55 μg / m3 (95% CI: 0.43-0.67) (2.1% / year; 95% CI: 1.6% -2.6%) from 1998 to 2012 respectively. In spite of the reduction of PM2.5 in some developed regions, the increase of PM2.5 in some developing regions has contributed to this global change. In East Asia, the proportion of people with PM2.5 levels above 35 μg / m3, the first target of the World Health Organization (WHO), rose from 51% in 1998-2000 to 70% in 2010-2012. In contrast, the proportion of North American population that is 10 μg / m3 higher than the WHO Air Quality Guidelines decreased from 62% in 1998-2000 to 19% in 2010-2012. There was a correlation between satellite inversion estimates and ground measurements in North America and beyond (r = 0.81; n = 210; slope = 0.68). Estimates for satellite inversion are low, suggesting that true global concentrations may be higher. [Conclusions] Satellite observations provide new insights into the global long-term changes in PM2.5 concentrations in the atmosphere. The satellite inversion estimates of PM2.5 and ground observations obtained from this study are available to the public.