Analysis On The Spatial And Temporal Distribution Of PM_2.5/PM₁₀ Ratio And Its Influencing Factors In Hebei Province

In recent years,the problem of air pollution in Hebei Province has attracted much attention.The characteristics of air pollution in this area are as follows:first,the pollution is mainly caused by particles;second,there is a great change in time and space.Under the background that the grid-based accurate monitoring platform has been almost fully covered,this paper uses the big data platform of air quality of Hebei Province,applies statistics and geographic information technology,takes PM_2.5/PM₁₀0 ratio as the main index to reflect the characteristics of regional air particle pollution,compares and analyzes the spatial characteristics of air particle pollution in the ecological areas of northern Hebei Province in 2019,and define the pollution characteristics from two aspects of human activities and meteorological factors.The main research results are as follows:?1?The spatial heterogeneity of PM_2.5/PM₁₀0 ratio in Hebei Province is very significant,which generally shows the spatial distribution characteristics of high in the east and low in the west,high in the south and low in the north.The PM_2.5/PM₁₀0 ratio is the highest in Coastal Plain?0.559?,the second in Central and Southern Hebei?0.542?,and the lowest in Bashang Plateau?0.439?.The PM_2.5/PM₁₀0 ratio in Hebei Province has obvious seasonal variation,which is highest in winter,followed by summer and autumn,and lowest in spring.The monthly variation characteristics of PM_2.5/PM₁₀0 ratio in each ecological region are also very obvious,showing a"W"type change,with peaks in February,July and December,and valleys in May and September.The PM_2.5/PM₁₀0 ratio in Hebei Province has obvious weekly variation,The Bashang Plateau and Northwest Hebei Province show a fluctuating and rising state from Sunday to Monday,The other five ecological areas show a"V"trend,with a typical high weekend and a low ratio of weekdays.?2?Different from the spatial distribution characteristics of PM_2.5/PM₁₀0 ratio,the spatial distribution trend of PM₁₀0 and PM_2.5.5 in each ecological area is higher in the south and lower in the north,and does not show a trend of high in the east and low in the west.The pollution of PM₁₀0 and PM_2.5.5 in Taihang Mountain and piedmont plain of south central Hebei is high,while the pollution of PM₁₀0 and PM_2.5.5 in the coastal plain in the East of Hebei is low.Seasonal changes are also slightly different,with the highest pollution levels in winter,followed by spring and autumn,and the lowest in summer.The monthly variation of PM₁₀0 and PM_2.5.5 mass concentrations in Hebei Province is more obvious.The monthly variation of PM₁₀0 and PM_2.5concentrations is mainly V-shaped,with two peaks and a low valley,the peak value mainly occurs in January March and October December,while the low value mainly occurs in August.Same as the PM_2.5/PM₁₀0 ratio,PM_2.5.5 and PM₁₀0 have obvious week rule,the PM mass concentration is high on weekends and low on weekdays.?3?The spatial distribution of wind speed in Hebei Province is high in the north and low in the south,and relative humidity is high in the east and low in the west.Regardless of the ecological area,the PM_2.5/PM₁₀0 ratio is lower when the wind speed is larger,and the opposite when the wind speed is smaller.The wind speed is higher in April-May and November,and lower in February,July-September.The time variation of relative humidity in Hebei Province is basically consistent with the PM_2.5/PM₁₀0 ratio,the higher the relative humidity,the higher the PM_2.5/PM₁₀0 ratio.The high relative humidity is mainly concentrated in summer,while the low relative humidity is mainly concentrated in spring.?4?The regional difference of economic density in Hebei Province is very obvious,and its spatial distribution has strong consistency with PM_2.5/PM₁₀0 ratio.The economic density of the eastern coastal plain and the eastern Plain Hebei is the highest,followed by the south central Hebei and Taihang Mountains,and the three ecological regions in the north are the lowest.Compared with PM_2.5.5 or PM₁₀,PM_2.5/PM₁₀0 ratio can better reflect the degree of anthropogenic air pollution emissions in Hebei Province.?5?Hebei Jidong Plain and Coastal Plain have the largest anthropogenic pollution emissions and PM_2.5/PM₁₀0 ratio,but the particulate pollution is relatively light.The man-made pollution emissions and the PM_2.5/PM₁₀0 ratio in Central and Southern Hebei are relatively large,and the particulate pollution is also very serious.The man-made pollution emissions and the PM_2.5/PM₁₀0 ratio in Taihang Mountains province are relatively small,but the degree of particulate pollution is comparable to that in Central and Southern Hebei.The pollution levels are lightly polluted in the three ecological regions of Northern Bashang Plateau,Yanshan Mountain in North Hebei and Northwest Hebei,among which the natural sources of PM₁₀0 are prominent in in Bashang Plateau and Northwest Hebei...