SO Emissions in China - Their Network and Hierarchical Structures.

SO emissions lead to various harmful effects on environment and human health. The SO emission in China has significant contribution to the global SO emission, so it is necessary to employ various methods to study SO emissions in China with great details in order to lay the foundation for policymaking to improve environmental conditions in China. Network analysis is used to analyze the SO emissions from power generation, industrial, residential and transportation sectors in China for 2008 and 2010, which are recently available from 1744 ground surface monitoring stations. The results show that the SO emissions from power generation sector were highly individualized as small-sized clusters, the SO emissions from industrial sector underwent an integration process with a large cluster contained 1674 places covering all industrial areas in China, the SO emissions from residential sector was not impacted by time, and the SO emissions from transportation sector underwent significant integration. Hierarchical structure is obtained by further combining SO emissions from all four sectors and is potentially useful to find out similar patterns of SO emissions, which can provide information on understanding the mechanisms of SO pollution and on designing different environmental measure to combat SO emissions.