Study On The Impact Of Urban Sprawl On Air Quality In Rapid Urbanization

Since the early 1980s,China's rapid growth has been accompanied by a rapid urbanization.This Growth in such a short period has not only led to an improvement in material wealth and a higher standard of living,but also caused severe environmental pollution,particularly air pollution,in many urbanized regions of China.Under the background of economic development,while focusing on the ecological protection in the city,research the relationship between urban sprawl and air quality,not only help to improve the urban sprawl mode,improve the quality of urban environment,for urban development policy,urban planning of the establishment and implementation in the future has important reference significance.This paper analyze the relationship between urban sprawl and air quality in the process of urbanization from regional and urban aspect,chooses Yangtze River Delta as the research object in the regional scale to identify the space-time characteristic of the regional air pollution during the period 2001-2012,choose economic development,population,land use,industrial structure,transportation and other factors,analyze the curve of the relationship between urban sprawl and air quality combine with Kuznets hypothesis,choose the land use regression model to analyze the linear relationship between urban land use and air quality,simulate urban spatial distribution characteristics of air pollution.The conclusions are as follows:In recent years the city primary pollutants are particulate matter in Yangtze River Delta,reducing the concentration of particulate matter(PM10)is the top priority of air pollution control.Air quality of Yangtze River Delta is in a state of improvement during 2001-2012,better air quality in the first four cities of Zhoushan,Ningbo,Taizhou and Shanghai,poor air quality in four cities of Nanjing,Taizhou,Hangzhou and Changzhou,the center of gravity shifting form northwest to southeast.16 cities in Yangtze River Delta can be divided to four types through air quality changes:stability,fluctuating,falling and lowered after.The analysis results showed that the existence of a U-shaped curve between urban development and air quality in Yangtze River Delta,and the turning point for the per capita GDP reached 115303.The growth of secondary industries and civilian car ownership had strong positive relationship with the air pollution index,the coefficient of secondary industry structure is higher than the civilian car ownership.Variables which related to PM2.5 of the highest in the land use regression model are industrial land area within 2km of the air quality monitoring sites,green space area within 2km of the air quality monitoring sites,public services area within 5km of the air quality monitoring sites,residential land area within 300m of the air quality monitoring sites.The validation test showed that spatial distribution map of PM2.5 predicted extremely well with an error rate less than 1%.And the return map results showed Nanjing high concentration of PM2.5 region into a continuous distribution trend,rendering ring Purple dumbbell-like distribution from Hexi-the main city area-Xianlin.PM2.5 concentrations of high value area will be significantly reduced with the implementation of 2020 urban land use planning,especially for the improvement of the main city area and Xianlin campus city,but air quality for the Hexi district surrounding Olympic center is not significantly improved,but has deteriorated.