Quantitatively evaluate the environmental impact factors of the life expectancy in Tibet, China.

Life expectancy is influenced by both innate human self-factors and external environmental factors. Due to the individual difference of self-factors, the external environment impacts on life expectancy are especially important under the geoscience perspective. However, few studies discussed impacts of various socioeconomic and environmental factors comprehensively, and quantitative analysis of multi-factors is lacking. We chose 13 potential factors of socio-economy, ecological environment, geological environment and geographical environment to quantitatively analyze their impacts and their interactive influences on Tibet's life expectancy in 2010 by using geographical detector (Geodetector) algorithm, and figure out their suitable ranges or types. Our results indicated that the high life expectancy at birth in Tibet are distributed like a strip; the main control factor of life expectancy in Tibet is socioeconomy, followed by geological environment; furthermore, the highest range of socioeconomic factors and the igneous rock exposed areas correspond to the maximum value of life expectancy at birth; factors of ecological environment have a certain impact on the life expectancy of Tibetan residents, while factors of geographical environment have few effects on the life expectancy. Lower radiation, moderate temperature and rainfall may have favorable effects on the increase in the life expectancy. The life expectancy of Tibet is mainly affected by socioeconomy, geological and ecological environment; interactions between these factors can increase the impact on the life expectancy of Tibet. Consequently, this study can better understand the impact factors of the life expectancy in Tibet and could provide a reference basis for local government's policy making of relocation and population management.