Spatio-temporal evolution of ecological environment quality in China from a concept of strong sustainability.

Based on the concept of strong sustainability, this paper builds a dynamic evaluation system on ecological environment quality from the concepts of ecological environment pollution and ecological environment management and puts forward the evaluation indexes including ecological environment pollution index (EPI), ecological environment management index (EMI), and ecological environment quality index (EQI). On this basis, kernel density estimation, Markov chain, Theil index, and dynamic SDM are used to reveal and explain the spatio-temporal evolution of ecological environment quality in China. The results were as follows. Overall, the EPI is decreasing while EMI and EQI are on the rise. In the long run, there is low possibility of upward and cross-level transition for EPI and EQI. The differences of EPI, EMI, and EQI are mainly caused by the regional differences. The regional differences have been reflected in the value of EPI, EMI, and EQI. It has been shown that the internal regional differences are continuously narrowing and the inter-regional differences are expanding. The convergence speeds of EPI, EMI, and EQI are 13.77%, 23.80%, and 9.69%, respectively. In the regional convergence test, different regions have shown different convergence speeds.