Research On The Changes Of Air Pollution In Beijing,Tianjin And Hebei Provinces

Short-term rapid urbanization has triggered a series of ecological and environmental problems,especially the urban and regional air pollution problems represented by fine particulate matter(PM_2.5)in recent years.It not only changes atmospheric visibility,but also potentially exposes the health of the exposed population.influences.In the past,many studies were based on single cities such as Beijing,Xi'an,and Zhengzhou,which were relatively polluted,but lacked comprehensive regional pollution research on urban agglomerations.Therefore,this study used the Beijing-Tianjin-Hebei urban agglomeration as the research area and selected the PM_2.5.5 concentration data,land cover classification data,population data,and basic geographic information data of 2000,2005,2010 and 2015 which were studied according to the“pattern-effect-regulation”theory.The main research results obtained were as follows:?1?Based on the inversion of PM_2.5.5 concentration data,the spatial distribution pattern of PM_2.5.5 concentration in Beijing-Tianjin-Hebei urban agglomeration was analyzed by GIS technology.The conclusions are as follows:The concentration of PM_2.5.5 in Beijing-Tianjin-Hebei urban agglomeration is low in the northwest,and high in the southeast;the average concentration showed an increasing trend;the proportion of PM_2.5.5 in the area above 70?g/m³ showed an increasing trend;among the average concentrations of different land cover types,the average concentration of PM_2.5.5 on the artificial surface was higher.?2?Based on the spatial distribution pattern of PM_2.5.5 concentration in Jing-Jin-Ji,Establishing GIS buffer zone analysis and an assessment model for the impact of urban air pollution on surrounding areas and further exploring the impact of urban PM_2.5.5 pollution on its surrounding areas.The conclusions of the study are as follows:The degree and scope of the impact of urban PM_2.5.5 pollution on its surrounding areas are on the rise,and this effect is manifested in two aspects:distance and direction:?1?the farther the majority of the cities are from the urban area,the greater the potential impact of cities on the surrounding areas;?2?From 2000 to 2015,the directional characteristics of PM_2.5.5 in most cities have significant differences in their directional characteristics.?3?The effect of PM_2.5.5 is not only reflected in the impact on the surrounding areas,but also closely related to the health of the population.According to the WHO Air Quality Guidelines and the combination of GIS technologies,a quantitative approach to the contribution of urbanization to the air pollution population was established.The results showed that from 2000 to 2015,the proportion of people affected by moderate PM_2.5.5 increased from 8%to 54%;The population migration and pollution changes are relatively large.As a result,the spatial differences between the population of PM_2.5.5 pollution-maintained areas and the newly added pollution areas and the natural growth have a significant difference in the contribution rate to the total population exposed to PM_2.5.?4?At the smaller scale of the Beijing-Tianjin-Hebei urban agglomeration,the landscape deployment will reduce the PM_2.5.5 effect,and the effect of improving air pollution will be more obvious.Reducing the area ratio of artificial surface and cultivated land types in landscapes on a single scale,increasing the area ratio of forest land and grassland,reducing the fragmentation of grassland and cultivated land types,and increasing the fragmentation degree of artificial surface and water landscape can reduce PM_2.5.5 air pollution.