Department of Physics and Atmospheric Science, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada.
Harvard-Smithsonian Center for Astrophysics , Cambridge, Massachusetts 02138, United States.
Environ Sci Technol. 2017 Oct 3;51(19):11185-11195. doi: 10.1021/acs.est.7b02530. Epub 2017 Sep 21.
We interpret in situ and satellite observations with a chemical transport model (GEOS-Chem, downscaled to 0.1° × 0.1°) to understand global trends in population-weighted mean chemical composition of fine particulate matter (PM). Trends in observed and simulated population-weighted mean PM composition over 1989-2013 are highly consistent for PM (-2.4 vs -2.4%/yr), secondary inorganic aerosols (-4.3 vs -4.1%/yr), organic aerosols (OA, -3.6 vs -3.0%/yr) and black carbon (-4.3 vs -3.9%/yr) over North America, as well as for sulfate (-4.7 vs -5.8%/yr) over Europe. Simulated trends over 1998-2013 also have overlapping 95% confidence intervals with satellite-derived trends in population-weighted mean PM for 20 of 21 global regions. Over 1989-2013, most (79%) of the simulated increase in global population-weighted mean PM of 0.28 μg myr is explained by significantly (p < 0.05) increasing OA (0.10 μg myr), nitrate (0.05 μg myr), sulfate (0.04 μg myr), and ammonium (0.03 μg myr). These four components predominantly drive trends in population-weighted mean PM over populous regions of South Asia (0.94 μg myr), East Asia (0.66 μg myr), Western Europe (-0.47 μg myr), and North America (-0.32 μg myr). Trends in area-weighted mean and population-weighted mean PM composition differ significantly.
我们通过一个化学输送模型（GEOS-Chem，下采样至 0.1°×0.1°）来解释原位和卫星观测结果，以了解细颗粒物（PM）的人群加权平均化学成分的全球趋势。1989-2013 年期间，观测到的和模拟的人群加权平均 PM 组成的趋势在北美地区的 PM（-2.4%/年）、二次无机气溶胶（-4.3%/年）、有机气溶胶（OA，-3.6%/年）和黑碳（-4.3%/年）方面非常一致，以及欧洲的硫酸盐（-4.7%/年）。在 1998-2013 年期间模拟的趋势也与 21 个全球区域中 20 个区域的人群加权平均 PM 的卫星衍生趋势有重叠的 95%置信区间。在 1989-2013 年期间，全球人群加权平均 PM 增加 0.28 μg myr，其中 79%可归因于 OA（0.10 μg myr）、硝酸盐（0.05 μg myr）、硫酸盐（0.04 μg myr）和铵盐（0.03 μg myr）显著增加（p < 0.05）。这四个成分主要驱动了南亚人口稠密地区（0.94 μg myr）、东亚（0.66 μg myr）、西欧（-0.47 μg myr）和北美（-0.32 μg myr）的人群加权平均 PM 趋势。面积加权平均和人群加权平均 PM 组成的趋势有显著差异。
