Study of the impact of regional economic development on ecological environment and its efficiency 并列题名：Study of the impact of regional economic development on ecological environment and its efficiency Research on the impact of urban economic development on environmental air quality in China Study of the effect of foreign direct investment on ecological environment Study on the impacts of urban development to its tourism efficiency 并列题名：Research on the impact of urban economic development on environmental air quality in China 并列题名：Study of the effect of foreign direct investment on ecological environment