Ecological Environmental Quality in China: Spatial and Temporal Characteristics, Regional Differences, and Internal Transmission Mechanisms

In recent years, ecological environmental problems such as the greenhouse effect, soil erosion, climate change, and biodiversity reduction have become more and more salient, and ecological environmental quality has gradually become a research hotspot. This paper constructs an index system for evaluating ecological environment quality based on the pressure-state-response (PSR) model, which contains three elemental layers, natural resources, ecological environment, and government inputs, measures the ecological environment quality index by using the "vertical and horizontal layer by layer" scatter degree method, and discusses the spatial and temporal evolution trends of ecological environment quality in each province and six regions in China during 2005-2020. This paper further measures the regional ecological environment quality differences by using the Thiel index and analyzes the transmission mechanism within the pressure-state-response model by using the mediation models. The results show that the ecological environment quality of all Chinese provinces and six regions has improved significantly during the period under study, the response system and state system scores have improved significantly, the unbalanced development of ecological environment quality within north China has improved the most, and there are significant direct and mediation effects among the subsystems within the ecological environment quality with high system transmission efficiency. Therefore, the government should improve the quality of the ecological environment by seeking cross-provincial linkage development, improving the level of pollution control, and formulating relevant standards and laws and regulations.