安徽省2017—2018年PM_(2.5)浓度时空分异特征

Spatio-Temporal Differentiation of PM_(2.5) Concentration in Anhui Province from 2017 to 2018

以2017—2018年安徽省133个空气质量监测站(国控点66个,省控点67个)228万条PM_(2.5)质量浓度数据为基础,基于空间自相关和地统计方法对该区PM_(2.5)浓度的时空分异特征进行分析。结果显示:安徽省年平均PM_(2.5)质量浓度为49.63μg/m^(3),88%的监测站点PM_(2.5)质量浓度超过国家环境空气质量标准二级限值;PM_(2.5)浓度呈现明显的冬季高、夏季低、春秋季适中的特征,日变化曲线呈双峰结构,峰值在09:00和22:00前后,低值在16:00—17:00;全省PM_(2.5)浓度全局Moran指数为0.6736,月度指数为0.3896~0.7456,均表现为空间聚集性,且冬季PM_(2.5)浓度的空间聚集性更强;局部空间自相关指数表明全省PM_(2.5)浓度呈西北高-高集聚、东南低-低集聚的特点,低值集聚区稳定在黄山市及其周边;全省PM_(2.5)浓度总体表现为由北向南递减的趋势,但受局部地形的影响,PM_(2.5)浓度在西部大别山和皖南山区出现明显的下降趋势。研究结果综合了国控点和省控点监测数据,更加详细地表征区域PM_(2.5)浓度的时空分异特征,为该区实施有效的环境污染防控提供重要参考。

Based on the 2.28 million pieces of PM_(2.5) concentration data from 133 air quality monitoring stations(66 national monitoring stations and 67 provincial monitoring stations)in Anhui Province from 2017 to 2018,its spatio-temporal differentiation characteristics of PM_(2.5) concentration were analyzed by spatial autocorrelation and geostatistical methods.The results showed that:The annual average PM_(2.5) concentration in Anhui Province was 49.63μg/m^(3),and the PM_(2.5) concentration in 88%of the stations exceeded the national ambient air quality standard secondary limit(35μg/m^(3)).PM_(2.5) concentration in Anhui Province showed obvious characteristics of high in winter,low in summer,and moderate in spring and autumn.The diunal variation curve of PM_(2.5) concentration showed a bimodal distribution,with peaks around 09:00 and 22:00,and low values around 16:00-17:00.Global Moran index of PM_(2.5) concentration across the province was 0.6736,and the monthly index was between 0.3896 and 0.7456,all of which showed spatial clustering pattern,and the clustering of PM_(2.5) concentration in winter was stronger.The local indicators of spatial association(LISA)indicated that PM_(2.5) in northwestern of Anhui was high-high clustering areas and southeast low-low clustering areas,while the low-value clustering areas was stable in Huangshan city and its surroundings.The concentration of PM_(2.5) in the whole province showed a decreasing trend from north to south,affected by the local topography,the concentration of PM_(2.5) in the western Dabie Mountains and southern mountains showed a significant decreasing trend.The spatial-temporal differentiation of PM_(2.5) concentration was characterized in more details by integrating the national control points and provincial control points,which could provide important references for the implementation of effective environmental policies.