中美贸易间隐含的大气污染物排放估算

随着中国能源消耗和国际贸易的快速增长,中国国际贸易尤其是中美贸易对气候变化的影响受到了广泛关注,但国际贸易对于大气污染的影响却鲜见系统研究. 基于环境投入产出法和结构分解分析法,采用基于技术的、自下而上的大气污染物排放清单,探讨了中美贸易隐含的大气污染物排放问题. 结果表明:由于中国对美国出口贸易顺差较大且商品污染物排放强度较高,造成了中国对美国的出口贸易隐含着较大的污染物排放逆差. 2007年中国对美国出口贸易隐含的SO₂、NO_x和PM_2.5的排放逆差分别为174.26×104、131.15×104和46.88×104t. 有行业针对性的污染物减排措施可以降低中美贸易隐含的污染物排放量；1997—2007年污染物燃烧排放因子和非燃烧直接排放强度的下降就可使出口贸易隐含的SO₂和PM_2.5排放量降低96.41%和226.26%. 占出口份额最高的机械类制造品的SO₂、NO_x和PM_2.5排放强度分别为72.63、58.38和20.74t/108元,低于所有出口商品的污染物排放强度的平均值, 中国应加强这种高附加值、低污染物排放的商品出口. 

Air Pollutant Emissions Embodied in China-US Trade

Export-based domestic energy use and related CO_2emissions in China have been widely argued in the scientific publications. About 20% of domestic China's CO_2emissions are caused by international exports, and such a large amount of emissions plays an influential role in the policy making of the international climate. Meanwhile, China's international trade also has a significant impact on other air pollutants besides CO₂. However, there was no comprehensive study about this important issue. The high levels of air pollutants caused by China's production intense domestic industry have a severe impact on human health as well as on ecosystems and biosphere. This is important to understand their drivers. Based on Environmental Extended Input-output Analysis (EEIO) and Structural Decomposition Analysis (SDA), as well as an updated bottom-up emission inventory of China, air pollutant emissions embodied in trade between China and the USA were estimated. Results showed that, in 2007, SO₂, NO_x and PM_2.5 embodied in China's exports to the USA were 178.46×104,7.22×104and 47.15×104t, respectively, while those embodied in China's imports from the USA were only 4.20×104,6.07×104and 0.27×104t, respectively. China had an emission deficit, and this is mainly because of its huge trade surplus and higher emission intensity. From 1997to 2007, SO₂, NO_x and PM_2.5 embodied in export from China to the USA grew by 159%, 244% and 94% respectively. Trade quantity scale-up accounted for most of the emission growth, although energy use was also improved. Besides, Owing to the sector-specific pollution control technologies. Owing to the pollution control technology of power plant and cement industry, SO_2and PM_2.5 embodied in China's export to the USA decreased by 96.41% and 226.26% from 1997to 2007respectively, when other driving forces remained constant. In 2007, emission intensities of manufactured goods, the main export from China to the USA, were 72.63t/108yuan for SO₂,8.38t/108yuan for NO_x, and 20.74t/108yuan for PM_2.5, lower than the average emission intensities of all China's export to US. The China's economy will continue to be driven by a large amount of international exports. Based on the results, we recommend China to further expand its sector-specific pollution control measures, to enlarge the export share of high value-added goods with lower emission-intensity and to implement emission tax or emission-intensive-export quota. This will not only help to reduce China's local air pollution and benefit its people but can also reduce the pollutants emissions embodied in China's export which will make its products for the international export market more attractive to foreign consumers.