Department of Physics and Atmospheric Science , Dalhousie University , Halifax , Nova Scotia B3H 4R2 , Canada.
Smithsonian Astrophysical Observatory , Harvard-Smithsonian Center for Astrophysics , Cambridge , Massachusetts 02138 , United States.
Environ Sci Technol. 2019 May 7;53(9):5071-5079. doi: 10.1021/acs.est.8b06875. Epub 2019 Apr 24.
Accurate data concerning historical fine particulate matter (PM) concentrations are needed to assess long-term changes in exposure and associated health risks. We estimated historical PM concentrations over North America from 1981 to 2016 for the first time by combining chemical transport modeling, satellite remote sensing, and ground-based measurements. We constrained and evaluated our estimates with direct ground-based PM measurements when available and otherwise with historical estimates of PM from PM measurements or total suspended particle (TSP) measurements. The estimated PM concentrations were generally consistent with direct ground-based PM measurements over their duration from 1988 onward ( R = 0.6 to 0.85) and to a lesser extent with PM inferred from PM measurements from 1985 to 1998 ( R = 0.5 to 0.6). The collocated comparison of the trends of population-weighted annual average PM from our estimates and ground-based measurements was highly consistent (RMSD = 0.66 μg m). The population-weighted annual average PM over North America decreased from 22 ± 6.4 μg m in 1981, to 12 ± 3.2 μg m in 1998, and to 7.9 ± 2.1 μg m in 2016, with an overall trend of -0.33 μg m yr (95% CI: -0.35, -0.31).
准确的数据对于评估长期暴露和相关健康风险至关重要。我们首次通过结合化学输送模型、卫星遥感和地面测量，估计了 1981 年至 2016 年期间北美的历史细颗粒物（PM）浓度。我们在有直接地面 PM 测量值的情况下对这些估计值进行了约束和评估，在没有这些测量值的情况下，我们使用 PM 测量值或总悬浮颗粒物（TSP）测量值的历史 PM 估计值来评估。在 1988 年及以后的时间段内，这些估计的 PM 浓度与直接的地面 PM 测量值通常是一致的（R 值为 0.6 到 0.85），与 1985 年至 1998 年期间从 PM 测量值推断出的 PM 值（R 值为 0.5 到 0.6）的一致性要稍差一些。从我们的估计值和地面测量值中得出的人口加权年平均 PM 趋势的对比高度一致（RMSD = 0.66 μg m）。北美的人口加权年平均 PM 从 1981 年的 22 ± 6.4 μg m 下降到 1998 年的 12 ± 3.2 μg m，再下降到 2016 年的 7.9 ± 2.1 μg m，总体趋势为-0.33 μg m yr（95% CI：-0.35，-0.31）。
