2014年-2019年杭州市主城区大气,PM2.5及金属含量监测分析

Monitoring and analysis of atmospheric PM 2.5 concentration and metal content in main urban areas of Hangzhou from 2014 to 2019

目的监测大气颗粒物PM2.5浓度及其金属含量,探索PM2.5及金属分布特征。方法 2014年9月-2019年12月每月定期连续采样7 d~8 d,每日23 h。样品称重后检测金属元素含量。结果 2015年-2017年大气PM2.5浓度逐年下降,冬春季高于夏秋季。2015年-2017年金属总浓度呈逐年下降趋势,并存在季节性,冬春季浓度高于夏秋季。2015年-2018年,铝(Al)、铅(Pb)、锰(Mn)、砷(As)、硒(Se)、锑(Sb)、铬(Cr)、铊(Tl)浓度呈逐年下降趋势;除汞外其他各元素平均浓度冬春季高于夏秋季。2015年-2018年金属总质量占比呈平稳下降趋势,春、夏、冬3个季节占比基本持平,秋季相对较低。结论主城区大气PM2.5浓度、金属总含量、大多数金属元素含量、金属总质量占比呈逐年下降趋势;大气PM2.5浓度、金属总浓度、大多数金属元素含量存在季节差异,总体表现为浓度冬春季大于夏秋季;金属元素总质量占比在春、夏、冬季基本持平,高于秋季。

Objective To monitor the concentration of atmospheric particulate matter PM2.5 and the content of metal in the main urban areas of Hangzhou,and to explore their distribution characteristics.Methods From September 2014 to December 2019,the sampling lasted for 7-8 consecutive days in the middle of each month and 23 hours per day.After weighing and pretreatment,the contents of antimony,aluminum,arsenic,beryllium,cadmium,chromium,mercury,lead,manganese,nickel,selenium and thallium were determined.Results From 2015 to 2017,the concentration of atmospheric PM2.5 decreased year by year,the average concentration in winter and spring were higher than those in summer and autumn.From 2015 to 2017,the total concentration of metal decreased year by year,which was seasonal.The concentration in winter and spring were higher than those in summer and autumn.From 2015 to 2018,the concentrations of Al,Pb,Mn,As,Se,Sb,Cr and TI decreased year by year.Except for mercury,the average concentration of metal elements in winter and spring were higher than that in summer and autumn.From 2015 to 2018,the proportion of total mass of metal elements decreased steadily.The proportion of spring,summer and winter were basically the sam e,and the proportion of metal elements were relatively low in autumn.Conclusion The concentration of atmospheric PM2.5,the total concentration of metal elements,the concentration of most metal elements and the proportion of the total mass of metal elements in the main urban areas decreased year by year.The concentration of atmospheric PM2.5,the total concentration of metal elements and the content of most metal elements were different from season to season.In spring,summer and winter,the total mass ratio of metal elements were the same,while in autumn those were relatively lower.