Distribution Characteristics Of Major Air Pollutants In Hexi Corridor And Source Analysis

With the deployment of"One Belt,One Road"and the stable promotion of"Western Development",the ambient air quality in the Hexi Corridor region is of great concern.The fragile ecological environment and complex topography of the region make its air environment condition not optimistic.Based on this,in order to clarify the spatial and temporal distribution patterns of major air pollutants in the Hexi Corridor region,explore the meteorological factors affecting the changes of pollutant concentrations,clarify the trajectories of pollutant transport,and determine their potential source areas.In this paper,the common air pollutant monitoring data in the Hexi Corridor region from 2003 to 2021were selected to determine the main air pollutants(PM_2.5,PM₁₀ and O₃)using the integrated pollution index evaluation method,and the spatial and temporal distribution patterns of the main air pollutants in the Hexi Corridor region were compared and analyzed using the statistical analysis method and the kriging interpolation method;by selecting the ground pressure,average air temperature,relative humidity,By selecting meteorological factors such as ground pressure,mean air temperature,relative humidity,mean wind speed and sunshine hours,and using Pearson correlation analysis,the influence of meteorological factors on the concentrations of major air pollutants was explored;then,the transport trajectories and potential source areas of major air pollutants were simulated by combining the meteorological data of the Global Data Assimilation System（GDAS）with backward trajectory clustering analysis and potential source contribution factor（PSCF）analysis.The main work and research results are as follows:（1）In terms of temporal variation,PM_2.5 and PM₁₀ show highly consistent interannual trends from 2003 to 2021,with large interannual fluctuations and maximum concentration increases of 37.36%and 34.24%,respectively,while O₃concentrations show moderate fluctuations and stable trends,with a maximum concentration difference of 6.74μg·m^-3.The seasonal average concentrations of the three pollutants vary significantly,with PM_2.5concentration varies as follows:spring>autumn>summer>winter,PM₁₀ concentration varies as follows:spring>summer>autumn>winter,with the lowest value in January and the highest value in April;O₃ concentration varies as follows:summer>spring>winter>autumn,with a gentle change in monthly average concentration.（2）In terms of spatial distribution,the spatial distribution patterns of PM_2.5 and PM₁₀on interannual,seasonal,and monthly time scales are clearly consistent,showing a latitudinal band distribution from southwest to northeast,with the median area following the same direction as the foothills of the Qilian Mountains,and clearly delineating the areas of high and low concentrations.The spatial distribution of O₃ concentrations on interannual and monthly scales is clearly opposite to the distribution of particulate matter,and there are great differences in the seasonal spatial distribution patterns.（3）Among the meteorological factors,average temperature,average wind speed and sunshine hours were positively correlated with the three major air pollutants,while air pressure and relative humidity were negatively correlated with pollutant concentrations.Among them,relative humidity and wind speed are the main meteorological factors affecting the variation of PM_2.5 concentration,relative humidity,wind speed and sunshine hours are the main meteorological factors affecting the variation of PM₁₀ concentration,and air pressure and sunshine hours are the main meteorological factors affecting the variation of O₃ concentration in the Hexi Corridor.（4）The results of backward trajectory clustering analysis and potential source contribution factor analysis show that PM_2.5 and PM₁₀ concentrations are mainly influenced by the western airflow,northwest airflow,northeast airflow and hourly southeast airflow,and the main potential source areas are western source area,northwest source area,north source area,local source area and a small area of southeast source area.O₃ concentrations are mainly influenced by the western airflow,northwest airflow,and the main potential source areas are western source area,northwest source area,north source area and south source area.The main potential source areas are the western source area,the northwestern source area,the northern source area and the southern source area.The air pollution problems in the Hexi Corridor region are mainly caused by particulate matter and ozone.This study analyzes the temporal and spatial distribution patterns,meteorological factor analysis,pollutant transport trajectories and potential source areas of three major air pollutants,with a view to providing a scientific and realistic basis for air pollution prevention and ecological environmental protection in the Hexi Corridor and the entire northwest arid region.