Trade-Induced Atmospheric Mercury Deposition over China and Implications for Demand-Side Controls

Mercury (Hg) is of global concern
because of its adverse effects
on humans and the environment. In addition to long-range atmospheric
transport, Hg emissions can be geographically relocated through economic
trade. Here, we investigate the effect of China’s interregional
trade on atmospheric Hg deposition over China, using an atmospheric
transport model and multiregional input–output analysis. In
general, total atmospheric Hg deposition over China is 408.8 Mg yr–1, and 32% of this is embodied in China’s interregional
trade, with the hotspots occurring over Gansu, Henan, Hebei, and Yunnan
provinces. Interprovincial trade considerably redistributes atmospheric
Hg deposition over China, with a range in deposition flux from −104%
to +28%. Developed regions, such as the Yangtze River Delta (Shanghai,
Jiangsu, and Zhejiang) and Guangdong, avoid Hg deposition over their
geographical boundaries, instead causing additional Hg deposition
over developing provinces. Bilateral interaction among provinces is
strong over some regions, suggesting a need for joint mitigation,
such as the Jing-Jin-Ji region (Beijing, Tianjin, and Hebei) and the
Yangtze River Delta. Transferring advanced technology from developed
regions to their developing trade partners would be an effective measure
to mitigate China’s Hg pollution. Our findings are relevant
to interprovincial efforts to reduce trans-boundary Hg pollution in
China.