银川市大气PM2.5中12种元素污染特征及变化趋势分析

目的 分析银川市大气PM2.5中12种元素(锑、铝、砷、铍、镉、铬、汞、铅、锰、镍、硒、铊)的污染特征及变化趋势,为大气污染进一步治理提供科学依据。方法 2015年1月至2018年2月每月定期在银川市采集大气PM2.5,采用称重法和电感耦合等离子质谱法(ICP-MS)分别测定大气PM2.5及其元素的质量浓度,分析其污染特征及污染趋势。结果 2017年银川市大气PM2.5年均质量浓度较2015年、2016年明显降低,P＜0.05;2015年、2016年呈现明显的季节变化,冬春高、夏秋低,2017年四季变化趋势不明显。银川市大气PM2.5中金属元素Al、Pb、Mn含量较高,其它元素含量相对较低;从2015年到2017年元素Al、Pb、Mn、Sb、Be、Cd、Ni、Tl的质量浓度呈递降趋势。结论 从2015年至2017年,银川市空气质量明显好转,但空气污染的治理仍需要加强。

Pollution characteristics and trends of 12 elements in PM2.5,Yinchuan

Objective To analyze the pollution characteristics and trends of 12 elements including Sb,Al,As,Be,Cd,Cr,Hg,Pb,Mn,Ni,Se and Tl in PM2.5 in Yinchuan,and to provide scientific basis for air pollution control.Methods Atmospheric PM2.5 was collected periodically from January 2015 to February 2018 in Yinchuan City.The mass concentration of PM2.5 and its elements were measured by weight method and inductively coupled plasma mass spectrometry(ICP-MS),and the pollution characteristics and pollution trends were analyzed.Results In 2017,the average annual concentration of atmospheric PM2.5 in Yinchuan was significantly lower than that in 2015 and 2016(P＜0.05).The PM2.5 concentrations were of obvious seasonal differences with highest in winter and spring and lowest in summer and autumn.The concentration changes in seasons of 2017 were not obvious.In 2015 and 2016,the contents of Al,Pb and Mn in atmospheric PM2.5 were high,and other elements were relatively low.From 2015 to 2017,the concentration of Al,Pb,Mn,Sb,Be,Cd,Ni and Tl showed a downward trend.Conclusion The air quality in Yinchuan City has improved significantly from 2015 to 2017,but air pollution control still needs to be strengthened.