Analysis Of Distribution Characteristics And Influencing Factors Correlation Of PM_2.5 In Shanghai

Since the reform and opening up,China has been committed to economic development.Economic growth will inevitably pollute the environment.Air pollution is one of the main forms of environmental pollution.PM_2.5 is the main pollutant of air pollution.As a fine particle with extremely small particle size,PM_2.5 has a very significant impact and effect on human health,atmospheric environment and even climate change,so it has gradually attracted the attention of the state and the research of relevant scholars.Firstly,this paper outlines the main ways of PM_2.5 entering indoor environment and its impact mechanism on human health and outdoor atmosphere.Secondly,taking Shanghai,a representative city in eastern China,as the research area,using the data from automatic monitoring of air environmental quality monitoring points in Shanghai and the meteorological data in Shanghai,firstly,the variation characteristics of PM_2.5 concentration from 2017 to 2018 in Shanghai were studied.then through the construction of regression model,taking into account meteorological factors and socio-economic factors,the variation characteristics of PM_2.5 concentration in Shanghai and the correlation of influencing factors are studied and discussed respectively.The conclusions are as follows:（1）The concentration of PM_2.5 in Shanghai has a relatively obvious rule or trend in the time dimension,which is mainly manifested as: in interannual variation,compared with 2017,the average annual concentration of PM_2.5 at each monitoring point in 2018 in Shanghai has been significantly reduced,and the average concentration at each station has decreased by 25.77%;In terms of seasonal variation,compared with 2017,the average PM_2.5 mass concentration in the four seasons of 2018 in Shanghai has been significantly reduced,with significant seasonal variation characteristics.The regularity is that the air pollution degree of PM_2.5 in winter is the most serious in the four seasons,and its average concentration is much higher than that in other seasons,while it is the lowest in summer.The average concentration in spring and autumn is between winter and summer,and the average concentration in these two seasons is roughly the same;In terms of monthly changes,compared with 2017,except March,July,August and October,the average mass concentration of PM_2.5 in other months of 2018 in Shanghai has been significantly reduced.The months with lower average concentration of PM_2.5 in 2018 are July to September,with concentrations of 25.4μg/m³,24μg/m³ and 21.3μg/m³ respectively;In terms of intra-week changes,the analysis starts from the longitudinal direction.Compared with 2017,the average concentration of PM_2.5 in 2018 decreased,with anaverage decrease of 44.31% in the whole week.Horizontally,the change of the concentration of PM_2.5 generally goes through the following processes: the first process shows an increasing trend from Monday to Tuesday,the second process shows no obvious change rule from Tuesday to Wednesday,the third stage shows a decreasing trend from Wednesday to Friday,the fourth stage shows an increasing trend from Friday to Saturday,and the last stage shows a decreasing trend from Saturday to Sunday;In terms of intra-day changes,compared with 2017,Shanghai has significantly decreased in all periods in 2018,with a decrease of 37.65%.The diurnal variation of PM_2.5 concentration in Shanghai from 2017 to 2018 showed wavy characteristics,and the time points corresponding to peak and valley points were basically the same.（2）Based on the main daily meteorological data（temperature,relative humidity,average air pressure,average wind speed and precipitation）,air quality index（AQI）and six indicators of air pollutants in 2018 in Shanghai,as well as socio-economic data,a multiple regression model is established to study the correlation between air pollutants,meteorological factors,socio-economic factors and PM_2.5 respectively.In the correlation analysis and regression analysis between the concentration of PM_2.5 and atmospheric pollutants,there is a significant correlation between PM_2.5 and SO₂,CO,NO₂ and O₃;In the correlation analysis between PM_2.5 concentration and meteorological factors,except that there is no obvious correlation between average wind speed and PM_2.5,other meteorological parameters have significant correlation with PM_2.5;In the regression analysis of PM_2.5 concentration and social and economic factors,only environmental protection investment is the significant influencing variable through stepwise regression.