Aerosols from Overseas Rival Domestic Emissions over North America
Aerosols from Overseas Rival Domestic Emissions over North America
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DOI：
10.1126/science.1217576
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发表时间：
2012-08
期刊：
影响因子：
56.9
通讯作者：
Hongbin Yu;L. Remer;M. Chin;H. Bian;Q. Tan;T. Yuan;Yan Zhang
中科院分区：
文献类型：
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作者：
Hongbin Yu;L. Remer;M. Chin;H. Bian;Q. Tan;T. Yuan;Yan Zhang
无国界的颗粒物
气溶胶对大气成分、空气质量和气候有着重要且往往是不利的影响。然而，气溶胶能够远距离传输，这限制了地方监管的效力。于等人（第566页）利用卫星数据估算了北美上空大气中多少气溶胶负荷源自海外。北美上空大约一半的沙尘和污染物来自亚洲、欧洲、非洲和中东。亚洲沙尘在总量中占比最大。此外，气候变化可能导致沙尘排放增加，这可能会抵消亚洲新兴经济体污染减排的成果。
北美上空空气中大约一半的颗粒物源自海外。许多类型的气溶胶寿命足够长，能够进行洲际传输，这使得它们可能对偏远地区的空气质量和气候变化有重要影响。我们估算，从海外抵达北美海岸的气溶胶质量与国内排放的颗粒物总质量相当。因此，控制国内颗粒物及其前体气体的排放不足以减轻气溶胶对北美的影响。进口的贡献主要来自亚洲的沙尘，而非燃烧产生的颗粒物。因此，即使亚洲新兴经济体减少工业排放，也可能因气象条件变化和潜在的沙漠化导致沙尘排放增加而被抵消。
Particles Without Borders Aerosols have important and often adverse impacts on atmospheric composition, air quality, and climate. However, aerosols can be transported long distances, limiting the efficacy of local regulations. Yu et al. (p. 566) used satellite data to estimate how much of the aerosol load in the atmosphere above North America originates overseas. Approximately half of the dust and pollution over North America comes from Asia, Europe, Africa, and the Middle East. Asian dust is the largest fraction of this total. Furthermore, potential increases in dust emissions in response to climate change might overwhelm any reductions in pollution from emerging Asian economies. Roughly half of all particulate matter found in the air above North America originates from sources overseas. Many types of aerosols have lifetimes long enough for their transcontinental transport, making them potentially important contributors to air quality and climate change in remote locations. We estimate that the mass of aerosols arriving at North American shores from overseas is comparable with the total mass of particulates emitted domestically. Curbing domestic emissions of particulates and precursor gases, therefore, is not sufficient to mitigate aerosol impacts in North America. The imported contribution is dominated by dust leaving Asia, not by combustion-generated particles. Thus, even a reduction of industrial emissions of the emerging economies of Asia could be overwhelmed by an increase of dust emissions due to changes in meteorological conditions and potential desertification.