Within a short period, rapid urbanization has reshaped China's eco-environment, especially at the beginning of the new century. Many studies have focused on the changes in certain physical indicators of eco-environments; however, these indicators cannot directly explain or only slightly consider the eco-environmental benefits of urban residents. Therefore, we analysed location-based population-weighted eco-environmental changes with indicators of the vegetation index and fine particulate matter (PM2.5) concentration at each pixel in China's prefectures and combined the changes with urban expansion to provide an expanded understanding of the transformation of China's urbanization and its eco-environmental dynamics. We discovered that China's urban areas expanded by 38,350 km2 from 2000 to 2015 with an increase in the population-weighted vegetation and PM2.5 concentration, but the changes varied among different periods. From 2005 to 2010, urban areas expanded by 20,970 km2 with an increase in the population-weighted vegetation and PM2.5 concentration. The period from 2000 to 2005 was a key transforming period that experienced an urban expansion of 9081 km2 with a decrease in the population-weighted vegetation and an increase in the population-weighted PM2.5 concentration. An urban expansion of 8299 km2 with an increase in the population-weighted vegetation and a decrease of the population-weighted PM2.5 concentration occurred from 2010 to 2015. The results of this research indicate that China's urbanization and environmental changes have facilitated eco-environmental improvements.
Keywords: Ecological quality; Environmental quality; Trade-off; Urbanization.