Analysis Of The Relationship Between Air Pollution And Economic Development Based On Phase Difference

Since the reform and opening up,rapid economic growth,industrial output has gradu-ally risen,and the accompanying air pollution problems have gradually become a widespread concern.During the study of air pollution,researchers exploring the relationship between air pollution and economic activities have mostly considered only the impact of economic development on air pollution.A key assumption here is that the spread of air pollution between cities is negligible.Whether there are statistical evidences for this assumption has become an urgent question to be answered.In this thesis,the Sichuan basin,Yangtze River Delta and North China are selected as the study areas.The question is investigated through the phase difference analysis of the time series of air pollutants.The impact of spatial spread of pollutants on air quality is further analysed along with the study of other factors affecting air pollution.In thesis,we first make some statistical inferences about the phase difference,includ-ing the estimation method,asymptotic distribution and test method.Based on the seasonal periodicity characteristic of the pollutant series,we fit the series to a trigonometric function to estimate the phase difference.Then,we prove that the initial phase estimates asymp-totically obey a normal distribution,so the phase differences calculated from the initial phase also asymptotically obey the same distribution.The Bootstrap method is used to re-peatedly sample the residuals of pollutant series.Then multiple sequences with the same properties as the original pollutant series are constructed.The newly generated series are brought into the test statistic to test the statistical significance of the phase difference.Sub-sequently,simulation experiments are designed to study the test performance.The phase differences of cities within the three regions are estimated by the above estimation method.After testing,the results show that the phase difference are statistically significant and can be used as air pollution indicators.Finally,by regression analysis of phase differences within the three regions,we find that economic activities and weather conditions are the main causes of air pollution.In ad-dition,in heavily polluted regions,the spread of pollutants between cities can significantly affect air quality.We also confirm that the relationship between urban GDP and PM_2.5in all three regions is consistent with the Environmental Kuznets Curve.Meanwhile,the rel-ative decrease in urban pollution emissions due to the increasing share of tertiary sector year by year is one of the reasons for the emergence of this curve.