Research On The Factors Affecting Air Quality In Chinese Cities

China has experienced 40 years of reform and opening up,national industrialization and urbanization are developing rapidly,our economic level has risen rapidly,But at the same time,due to the extensive development of China in the long run,urban environment is overwhelmed,China often has problems such as climate anomalies and serious haze.These phenomena indicate that there are problems that cannot be ignored in China's environmental conditions and air quality conditions.,It affects people's normal life and urban development.The government first mentioned the ecological maintenance and environmental protection work to the national strategic height,and proposed the strategic concept of building a "green water and green hills".In this context,the paper uses the indicators of urban air quality,urban development level and urban air self-purification capacity of 332 prefecture-level administrative units in 2017 to study the urban development and air self-purification capacity,explores the spatial layout and spatial influence factors of air pollution in 332 prefecture-level administrative units across the country.First of all,we calculate the daily AQI index and daily precipitation of the various units in the period from 2017.1.1 to 2017.12.31,and obtain the average AQI and the total annual precipitation of the air quality index of each city in the whole year,they respectively characterize their air quality and air self-purification,descriptive statistical analysis of them.,we have identified regional differences and distribution characteristics of air pollution and air self-purification capacity.In order to study the urban development status of local administrative units,we construct an indicator system for measuring urban development status from four aspects: economic urbanization,population urbanization,living service urbanization and environmental urbanization.We conduct principal component analysis to obtain the principal component values of the main information,and then construct a comprehensive score of urban development of local administrative units to represent the comprehensive level of urban development.We use the principal component values of each city and the 2017 AQI index to construct a spatial evolution tree to reveal the spatial distribution of urban development level and air pollution status.Next,we use urban development scores and urban precipitation as the main factors affecting air quality,and construct a spatial measurement model of the overall air pollution indicator AQI and specific six pollutants.After comparing the spatial lag model and the spatial error model,we choose the most suitable model for spatial regression analysis.We conduct an empirical study on the impact of urban development level and air self-purification capacity on air pollution,give practical advice based on the conclusions of the study.Based on the above analysis,our conclusions are as follows: In 2017,air pollution in various administrative units in China was concentrated.Air pollution is radial around the North China region,the degree of pollution gradually weakens to the surrounding areas in North China.Areas with serious air pollution are concentrated in Xinjiang,North China and Central China.The spatial variation of precipitation in various administrative units in China is quite different,and it shows a trend of decreasing from the southeast to the northwest.The areas with higher comprehensive scores of urban development in China are the southeast coastal areas and the provincial capital cities.It shows that China's urban development is now entering the era of "strong provincial capital".The spatial analysis results show that there is a strong positive spatial autocorrelation between the urban air AQI value and the specific six pollutant concentration values.Urban air quality conditions are affected by many aspects.There is a positive correlation between urban development score and air pollution degree.Higher urban development scores will increase air pollution.There is a negative correlation between the degree of urban air pollution and urban precipitation.Precipitation has a significant effect on the concentration of pollutants in urban air.In addition,the number of urban population also has a certain positive impact on the changes of urban air quality.AQI values and most air pollutant concentration values have strong spatial lag.Air quality in adjacent areas severely affects air quality in the region.In the top-level design of urban development,we should fully consider the self-purification ability of urban air,adjust the structure and layout of urban development in a timely manner.We can't bury our heads and cross the bottom line of the environment and the air.