Study On The Temporal-spatial Correlation Of Air Quality And Socio Economic Factors In Major Cities Along The Yellow River

The improvement of ambient air quality in cities along the Yellow River is an important link to promote ecological protection and high-quality development of its watershed.This paper is based on the air quality index(AQI)of 71 major prefecturelevel cities(states and leagues)along the Yellow River from 2015 to 2019 and the data of 6 constituent pollutants,using statistical analysis,inverse distance weighting method,and empirical orthogonal function method(EOF)And the exploratory spatial data analysis method(ESDA),etc.,combined with two-dimensional and three-dimensional visualization to explore the temporal and spatial distribution,abnormal changes,and spatial agglomeration characteristics of air quality.Taking the 61 major prefecture-level cities along the Yellow River in 2016 and 2017 as examples,based on the city’s AQI and socio-economic data,a social and economic impact indicator system for the air quality of major cities along the Yellow River was constructed.BP neural network was introduced to improve the DEMATEL model,and identified and analyzed The key socio-economic influencing factors of air quality and the relationship between the factors;the introduction of OLS and GWR models combined with two-dimensional and three-dimensional visualization,explored the temporal and spatial correlation characteristics of air quality and key socio-economic influencing factors.Based on the research results,effective measures to improve air quality in cities along the Yellow River were discussed.The main conclusions are as follows:(1)From 2015 to 2019,the air quality in the study area improved year by year,and O3 gradually replaced PM10 as the annual primary pollutant.The air quality has a seasonal characteristic of "good autumn and bad winter,middle spring and summer",and there is a trend of getting better in winter and getting worse in summer.The monthly average value of AQI presents a "W" distribution,with the worst air quality in January and the best air quality in September;the O3 concentration presents an "inverted V" distribution.The key control months are from May to July,with PM2.5,PM10,and SO2.The five pollutants,such as,NO2 and CO,are distributed in a "U" shape,and the key control months are January and December.(2)The overall air quality is characterized by the spatial distribution of "the West is good and the East is poor".The average value of AQI in various regions has decreased to varying degrees with the change of the year,and the decline is most obvious in the downstream areas.The air pollution areas show the characteristics of "big winter and small autumn,middle spring and summer",the smallest in August and September,the largest in December,the key control months are 1,2,5,November,and December,and the key control areas are Henan,Shandong,and Shanxi In May,most cities in Shaanxi and some cities in Gansu and Ningxia need to focus on controlling some cities in Inner Mongolia at the junction of the upper and middle reaches.(3)The local characteristics of annual abnormal changes in air quality are obvious,and there is a pattern of mutual transport of air pollution in different years at the upper,middle reaches and the middle and lower reaches of the junction.The seasonal and monthly abnormal changes are similar,and there are two patterns of change: "consistent throughout the region" and "southeast-northwest".Air pollution is transported from the southeast to the northwest from March to July,and the northwest is transported to the southeast during the rest of the month.The law of change.(4)Air quality has a strong positive spatial correlation on the annual,seasonal,and monthly scales.The agglomeration characteristics first weaken and then increase with the change of the year,continue to increase with the seasons,and fluctuate significantly with the monthly changes.The high value of AQI is mainly concentrated in the lower reaches of the east,and the low value is mainly concentrated in the upper reaches of the west.The range of high-value agglomeration varies with the year and seasonal fluctuations.In May,there is a double-center distribution in the northwest-southeast region,and the remaining months are in a single-center distribution in the east.The low-value agglomeration range generally increases with the year and seasonal changes,the smallest in spring,the largest in winter,January and February are double-centered in the west-north region,and the rest of the months are single-centered in the west.(5)Industrial smoke and dust emissions and GDP per capita are strong driving factors for air quality and fundamental factors for regulating air quality.Industrial smoke and dust emissions are positively correlated with AQI.The key control areas are Gansu,Ningxia,and most cities in southern Shaanxi.Per capita GDP and AQI were mainly negatively correlated in 2016,and were mainly positively correlated in 2017.The key control areas are Qinghai and Gansu.,Ningxia and most cities in western Shaanxi.(6)The total industrial electricity consumption and road freight volume are strong characteristic factors of air quality,which are mainly positively correlated with AQI,and are the most direct factors regulating air quality.The regression coefficient of total industrial electricity consumption gradually weakens from north to south,and the key control areas are Gansu,Ningxia,most cities in western Shaanxi,and some cities in Shanxi and northern Inner Mongolia;the regression coefficient of road freight volume gradually weakens from west to east,and the key control areas are Most cities in Gansu,Ningxia,and Shaanxi,and some cities in Shandong and Henan.