A complex network perspective on embodiment of air pollutants from global oil refining industry.

The air pollutants emitted from oil refining industry could be transferred across borders through the increasingly complex global trade network. However, the specific structural features of the network remain unclear. Based on the Multi-regional Input-output method and complex network theory, we make a first attempt to trace six oil refining air pollutants embodied in the international trade. The results show that the overall character of the global oil refining air pollutants flow network exhibits small-world behavior, and each node of the network is strongly connected. Therefore, the refining emissions mitigation measures of one node could efficiently radiate to the other nodes connected to it, which provides essential opportunities for collaborative emissions reduction among countries. Besides, the individual characteristics of each node are distinguished, several key nodes dominate the embodied emissions throughout the global oil refining air-pollutants flow network. For specific countries, the United States, China, Japan, and the United Kingdom are the hub economics in importing embodied pollutants in the network, while Russia and Canada are the key exporters. Similarly, the critical paths with large flow still come from the trade between these key nodes. Our estimated results have great policy implications for reducing air pollutants emitted from oil refining industry and also have profound implications for environmental regulation and protection in the world.