Set pair analysis for urban ecosystem health assessment

Set pair analysis (SPA) is introduced to assess the urban ecosystems, through which the approximate degree of urban ecosystem health to the optimal set is calculated to describe the health level of the urban ecosystems by combining multiple health indices. The urban ecosystem health levels of Beijing, Dalian, Shanghai, Wuhan, Xiamen and Guangzhou from 1995 to 2003 are thereafter evaluated using SPA. The results show that the urban ecosystem health states of Xiamen and Guangzhou is the best during the study period, while the health states of the others changes over time. Particularly, the change of Beijing’s urban ecosystem health from 1992 to 2003 is analyzed in detail.