Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China.
Proc Natl Acad Sci U S A. 2014 Feb 4;111(5):1736-41. doi: 10.1073/pnas.1312860111. Epub 2014 Jan 21.
China is the world's largest emitter of anthropogenic air pollutants, and measurable amounts of Chinese pollution are transported via the atmosphere to other countries, including the United States. However, a large fraction of Chinese emissions is due to manufacture of goods for foreign consumption. Here, we analyze the impacts of trade-related Chinese air pollutant emissions on the global atmospheric environment, linking an economic-emission analysis and atmospheric chemical transport modeling. We find that in 2006, 36% of anthropogenic sulfur dioxide, 27% of nitrogen oxides, 22% of carbon monoxide, and 17% of black carbon emitted in China were associated with production of goods for export. For each of these pollutants, about 21% of export-related Chinese emissions were attributed to China-to-US export. Atmospheric modeling shows that transport of the export-related Chinese pollution contributed 3-10% of annual mean surface sulfate concentrations and 0.5-1.5% of ozone over the western United States in 2006. This Chinese pollution also resulted in one extra day or more of noncompliance with the US ozone standard in 2006 over the Los Angeles area and many regions in the eastern United States. On a daily basis, the export-related Chinese pollution contributed, at a maximum, 12-24% of sulfate concentrations over the western United States. As the United States outsourced manufacturing to China, sulfate pollution in 2006 increased in the western United States but decreased in the eastern United States, reflecting the competing effect between enhanced transport of Chinese pollution and reduced US emissions. Our findings are relevant to international efforts to reduce transboundary air pollution.
中国是世界上人为空气污染物的最大排放国，可测量数量的中国污染通过大气传输到其他国家，包括美国。然而，中国的大量排放是由于为外国消费制造商品造成的。在这里，我们通过经济排放分析和大气化学输送模型，分析了与贸易相关的中国空气污染物排放对全球大气环境的影响。我们发现，在 2006 年，中国人为排放的二氧化硫、氮氧化物、一氧化碳和黑碳中，分别有 36%、27%、22%和 17%与出口商品生产有关。对于所有这些污染物，约有 21%的出口相关中国排放归因于中国对美国的出口。大气模拟表明，2006 年，出口相关的中国污染传输导致美国西部年平均地表硫酸盐浓度增加 3-10%，臭氧浓度增加 0.5-1.5%。这种中国污染还导致 2006 年洛杉矶地区和美国东部许多地区的臭氧标准超标天数增加一天或一天以上。从每天来看，出口相关的中国污染最多可使美国西部的硫酸盐浓度增加 12-24%。随着美国将制造业外包给中国，2006 年美国西部的硫酸盐污染增加，但美国东部的污染减少，这反映了中国污染传输增强和美国排放量减少之间的竞争效应。我们的研究结果与减少跨境空气污染的国际努力有关。
