Study On The Nexus Between Urbanization And PM_2.5Related Health Impacts In China

In recent years,China is experiencing serious air pollution characterized by extremely high concentration of fine particulate matter(PM2.5).Rich evidence has proved that PM2.5 was significantly associated with negative mental health as well as a range of negative physical health symptoms especially mortality.Meanwhile,as an important driving force,new type urbanization in China would have complex and dynamic impacts on PM2.5 related health effects through different pathways,including scaled effects of energy consumption,population migration,infrastructure improvement,promotion of medical services.However,due to the lack of both historical PM2.5 data and localized associations between air pollution and mental Health in China,prior studies on evaluating the chronic health burdens attributable to long-term PM2.5 exposures are controversial and the studies on evaluating PM2.5 related mental health are also extremely lacking.This greatly limits the quantitative study of the dynamic associations between urbanization and PM2.5 related health effects.In this context,this thesis assesses the chronic health burdens and wellbeing losses attributable to PM2.5 exposures in China during 2004-2012,on the basis of which Stochastic Impacts by Regression on Population,Affluence,and Technology(STIRPAT)model was applied in estimating the marginal PM2.5 related deaths caused by urbanization.The main conclusions are as follows.In the aspect of PM2.5 related premature deaths,this thesis estimates the temporal and spatial distribution of premature deaths attributable to historical PM2.5 in China using the relative risk model based on high-resolution satellite-based PM2.5 concentrations.Results showed that national PM2.5 related deaths increased from approximately 807 thousand cases in 2004 to 1250 thousand cases in 2012,which partly supported the recent findings in Global Burden of Diseases Study.As consequences of the interactions of air quality change,population growth and migration;premature deaths attributable to PM2.5 in China increased significantly before 2007 and then showed a slightly decreased trend with some flunctuations.This finding enriches the existing knowledge body based on PM10 data or inconsecutive PM2.5 data.In addition,the health burden attributable to PM2.5 exhibited strong spatial variations,with high attributable deaths concentrated in regions including the Beijing-Tianjin Metropolitan Region,Yangtze River Delta,Pearl River Delta;Sichuan Basin,Shandong,Wuhan Metropolitan Region,Changsha-Zhuzhou-Xiangtan,Henan,and Anhui.The priority areas of air pollution prevention and control delineated from the point of pollution control failed to fully cover the spatial hotspots of PM2.5 related deaths.Therefore,we recommended that the priority areas should be adjusted in the future to better reflect the hotspots of health burdens.In the aspect of PM2.5 related mental health losses,this thesis firstly constructed a structural equation model to quantify the pathways through which air pollution and income affect self-reported wellbeing based on the questionnaire data at individual level in Nanjing and then calculated the marginal substitution rates between PM2.5 and income for different income groups,which could be seen as the corresponding monetized values of wellbeing brought by 1?g/m3 PM2.5 increase in these groups.Based on historical PM2.5 in 31 provinces of China,we modified the monetized values of wellbeing brought by 1?g/m3 PM2.5 increase at provincial level using the income distribution data and then applied the valuation results in assessing the monetized wellbeing losses caused by PM2.5 change during the period of 2004-2012.Results showed that objective air pollution had indirect effects on self-reported wellbeing through risk perception,but had no direct effects.This challenged the traditional approaches that usually directly linked objective air pollution and wellbeing.We also found that on the national average,1 ?g/m3 annual pM2.5 increase was associated with 0.45-1.70 Yuan wellbeing losses per capita per day.From 2004 to 2012,the year-by-year newly increased monetized wellbeing losses attributable to PM2.5 in China increased significantly before 2007 and then showed a slightly decreased trend with some flunctuations.Overall,the accumulated newly increased monetized wellbeing losses attributable to PM2.5 in China from 2004 to 2012 were approximately equal to 58.4 billion Yuan,accounting for 0.02%of accumulated gross domestic productions.The accumulated newly increased monetized wellbeing losses attributable to PM2.5 exhibited strong spatial variations with the high values in Henan,Shandong and Hebei,which overlapped with the spatial hotspots of PM2.5 related deaths.Therefore,we recommended the government paied more attention to those areas.Based on refined estimates of PM2.5 related deaths in China and panel data on urbanization rates,population,income,share of secondary industries for 339 prefecture-level cities during the period of 2004-2012,this thesis adopted both fixed-effects model and random-effects model to measure the marginal PM2.5 related deaths caused by urbanization under the framework of STIRPAT model.Results showed that a 1%increase in urbanization rates was associated with a 0.32%,0.14%,and 0.50%increase in PM2.5 related deaths of lung cancer,stroke,and ischemic heart disease.Income level has non-linear modification effects on the associations between urbanization and PM2.5 related deaths with an inverted U shape.Specifically,in four income groups(low to high)a 1%increase in urbanization rates was associated with a 0.12%,0.72%,0.37%and 0.30%increase in PM2.5 related deaths of lung cancer,respectively.Moreover,we also found that one of the effective ways to reduce PM2.5 related mortality brought by urbanization in Chinese cities,was to decouple the income improve-ment and the expansion of secondary industry in the urbanization process.The findings in this study provides a scientific basis for to rgeted air quality management strategies in China from the perspective of public health protection;and promote the efforts in incorporating the concept of wellbeing into the framework of cost-benefits analysis of air pollution control policies.The quantitative descriptions on the dynamic associations between urbanization and PM2.5 related health effects provide important policies implications for avoiding the potential adverse health effects in the future urbanization process.