西安市大气污染物时空特征及其与土地利用因素的关系

Temporal and spatial characteristics of air pollutants in Xi’an city and their relationship with land use factors

为了解西安市空气质量时空变化特征,探讨大气污染物质量浓度与土地利用类型的关系。使用2017年西安市空气质量监测数据和土地利用数据,基于经验正交函数(empirical orthogonal function,EOF)、空间插值和泰森多边形(Thiessen polygon)法分析西安市空气质量指数和主要大气污染物质量浓度时空变化特征,探讨土地利用类型对其的影响。结果表明:西安市大气污染物质量浓度在空间分布上呈现西北高、东南低的特征,在时间变化上呈现冬季>春秋季>夏季的“U”型特征;土地利用类型的变化会对大气污染物质量浓度产生一定的影响,其中PM_(2.5)、PM_(10)等污染物与耕地、林地、草地及水体的比例呈正相关,与建设用地及裸土地的比例呈负相关。根据大气污染物质量浓度回归模型显示,模型R2值均在0.65以上,拟合度较好。研究结果可为西安市大气污染物质量浓度预测、大气污染防治及今后的城市规划提供科学合理的建议。

To understand the spatial and temporal variation characteristics of air quality in Xi’an city,based on the air quality monitoring data and land use data of Xi’an city in 2017,also based on empirical orthogonal function(EOF),spatial interpolation and Thiessen polygon method,the spatial and temporal variation characteristics of air quality index and main air pollution concentration in Xi’an city were analyzed,the impact of land use types were explored,and the relationship between air pollutant concentration and land use was discussed,too.The results show that the spatial distribution of air pollutant concentration in Xi’an city is higher in northwest and lower in southeast,and the“U”shape is winter>spring and autumn>summer in time variation;the change of land use type will have a certain impact on air pollution concentration,among which PM_(2.5),PM_(10)and other pollutants are positively correlated with the proportion of cultivated land,woodland,grassland and water bodies,and negatively correlated with the proportion of construction land and bare land.According to the regression model of air pollutant concentration,R2 of the model is above 0.65,and the fitting degree is good.The results can provide scientific and reasonable suggestions for Xi’an city air pollutant concentration prediction,air pollution prevention and future urban planning.