2000-2018年黄河流域县域尺度PM_(2.5)污染时空格局

Analysis of Temporal and Spatial Patterns of PM_(2.5) at County-level in the Yellow River Basin from 2000 to 2018

近年来,与PM_(2.5)有关的大气污染状况和改善问题成为公众关注的焦点.基于2000-2018年黄河流域县域PM_(2.5)浓度数据,采用空间自相关分析和标准差椭圆法对黄河流域PM_(2.5)浓度的时空格局演变特征进行分析.结果表明:(1)2000-2018年黄河流域地区PM_(2.5)年均浓度总体上呈现波动变化,其中2000-2013年呈现波动增长趋势,平均增长率达到2.02%,2014-2018年PM_(2.5)浓度逐年下降,但研究期内黄河流域PM_(2.5)年均浓度值均高于年均限值(35μg·m^(-3)).(2)黄河流域PM_(2.5)浓度的地区差异较大,形成西南部和内蒙古中部浓度低,中东部的山西、山东和河南省浓度高的空间格局.(3)黄河流域PM_(2.5)污染具有显著空间正相关特征.除2000年高值聚集区分布在甘肃省中南部、内蒙古自治区西部(阿拉善盟)、宁夏回族自治区、陕西省西南部和河南省中西部外,其他年份较为稳定地分布在河南和山东两省.低值集聚区主要分布在青海省、“内陕山”交界地带.PM_(2.5)污染总体上呈现出“西北-东南”方向分布格局,覆盖区域从甘肃省东南部到山东省中西部,从椭圆面积来看,2000-2012年PM_(2.5)污染范围缩小,但2012-2018年有所扩大.

In recent years,the status and improvement of air pollution related to PM_(2.5)have become the focus of public attention.Based on the PM_(2.5)concentration data in the Yellow River Basin from 2000 to 2018,the spatial autocorrelation analysis and standard deviation ellipse method were used to analyze the temporal and spatial pattern evolution characteristics of PM_(2.5)concentration in the Yellow River Basin.The results show that:(1)The annual average concentration of PM_(2.5)in the Yellow River Basin from 2000 to 2018 showed a fluctuating change as a whole,of which,from 2000 to 2013,it showed a fluctuating growth trend,with an average growth rate of 2.02%.From 2014 to 2018,the PM_(2.5)concentration decreased year by year.However,the annual average concentration of PM_(2.5)in the Yellow River Basin was higher than the annual average limit(35μg·m^(-3))during the study period.(2)The regional differences of PM_(2.5)concentration in the Yellow River Basin are relatively large,forming a spatial pattern with low concentrations in southwest and central Inner Mongolia,and high concentrations in Shanxi,Shandong and Henan Provinces in central and eastern parts,and the regional differences in pollution continue to expand.(3)PM_(2.5)pollution in the Yellow River Basin has a significant positive spatial correlation.Except for the high-value clusters in 2000,which were distributed in central and southern Gansu Province,western Inner Mongolia Autonomous Region(Alxa League),Ningxia Hui Autonomous Region,southwestern Shaanxi Province,and central and western Henan Province,other years were relatively stable in Henan and Shandong provinces.The low-value agglomeration areas are mainly distributed in the junction of Qinghai Province and the"Inner Shaanxi Mountains".In general,PM_(2.5)pollution shows a"northwest-southeast"distribution pattern,covering areas from southeastern Gansu Province to central and western Shandong Province.From the perspective of the ellipse area,the PM_(2.5)pollution area shrank from 2000 to 2012,but the main scope of PM_(2.5)pollution expanded from 2012 to 2018.