重庆市主城区PM2.5时空变化特征研究

Study on the temporal and spatial variation characteristics of PM2.5 in the main urban area of Chongqing

基于2013~2018年监测数据,采用GIS空间重心转移等方法分析了重庆市主城区PM2.5区域空间分布特征。结果表明:重庆主城区PM2.5年均值呈逐年下降趋势,各区PM2.5下降趋势逐渐趋同,平均变化率为-11.29%,下降速率优于全国平均水平;冬季日均值超标率为20.14%,阶段性上升趋势明显;周循环变化特征呈U型,日循环小时变化特征呈W型;主城区PM2.5重心一直在江北区移动,冬季空间整体特征为西北高、东南低、核心区高、郊区低。

Based on the monitoring data from 2013 to 2018,the spatial distribution characteristics of PM2.5 in the main urban area of Chongqing were analyzed using methods such as GIS spatial center of gravity analysis.The results show that the annual average value of PM2.5 in the main urban area of Chongqing shows a downward trend year by year,with an average change rate of-11.29%,which is better than the national average level.The decline trends of PM2.5 concentration in different districts gradually converges.The daily average overwhelming rate in winter is 20.14%,and the upward trend is obvious in stages.The characteristics of the weekly cycle change are"U-shaped"and the characteristics of the daily cycle hour change are"W-shaped".The PM2.5 pollution center in the main urban area has been moving in the Jiangbei District.The overall spatial characteristics in winter are"high in the northwest,low in the southeast"and"high in the core area,and low in the suburbs".