武汉市地铁站空气PM_(10)中化学元素的污染特征及来源

Pollution characteristics and sources of chemical elements in PM_(10)at Wuhan subway stations

目的探讨武汉市地铁站空气PM_(10)中铍(Be)、硼(B)、钪(Sc)、镉(Ge)、钼(Mo)、银(Ag)、铟(In)、汞(Hg)、铊(Tl)、铋(Bi)10种化学元素的污染特征及来源。方法于2018年冬季至2019年秋季,采用中流量空气总悬浮粒采样器对武汉市17个地铁进站口及地下一层大气PM_(10)进行样品采集,并对其中10种化学元素进行连续测定。结果武汉市地铁PM_(10)中10种元素在秋季的浓度高于其他季节,秋季在进站口和地下一层金属总浓度分别为10489.35μm/m^(3)和7809.73μm/m^(3)。Sc、Ge、In、Bi这4种元素在进站口和地下一层的浓度均高于其他元素,最高值分别达到98.9、100.4、100.7、117.6μm/m^(3)。富集因子分析显示,Be主要来自燃煤源,B、Mo受矿业开采和燃煤的共同作用,Sc、Ge、In、Bi受矿业开采和交通运输的共同作用,Ag主要来自矿业开采和废弃物排放,Hg、Tl受交通运输和废弃物排放的共同作用。结论武汉市地铁PM_(10)中10种元素主要来自矿业开采源、燃煤源、交通运输源、废弃物排放源。对武汉市地铁PM_(10)的质量监测结果可用于研究化学元素在大气中的来源及变化规律,为制定更加科学的环境保护政策提供依据。

Objective To understand the pollution characteristics and sources of 10 kinds of chemical elements in PM_(10),beryllium(Be),boron(B),scandium(Sc),cadmium(Ge),molybdenum(Mo),silver(Ag),indium(In),mercury(Hg),thallium m(Tl)and bismuth(Bi)at Wuhan subway stations.Methods In the four seasons of spring,summer,autumn and winter,medium-flow air total suspended particulate samplers were used to collect atmospheric PM_(10)samples at 17 subway entrances and the underground layer in Wuhan City,10 trace elements were measured continuously at subway entrances and the first basement level.Results The concentration of ten elements in PM_(10)in autumn was significantly higher than that in other seasons.At the entrance and the first basement floor in autumn,the total concentrations of metals were 10489.35μm/m^(3)and 7809.73μm/m^(3)respectively.The concentrations of the four elements Sc,Ge,In,and Bi at the entrance and the first basement floor were higher than those of other elements,with the maximum values reaching 98.9μm/m^(3),100.4μm/m^(3),100.7μm/m^(3),and 117.6μm/m^(3)respectively.The enrichment factor analysis indicated that Be mainly originated from coal combustion sources;B and Mo were influenced jointly by mining and coal combustion.Sc,Ge,In,and Bi were affected jointly by mining and transportation.Ag mainly derived from mining and waste emissions.Hg and Tl were influenced jointly by transportation and waste emissions.Conclusion PMF source analysis shows that the 10 elements in Wuhan subway PM_(10)mainly come from mining sources,coal burning sources,transportation sources and waste emission sources.Pollution from coal burning sources in autumn and winter results in significantly higher Hg content.In spring and winter,lower temperatures and weaker air circulation are not conducive to the diffusion of pollutants,making waste emissions the main source.The quality monitoring results of PM_(10)in Wuhan subway can be used to study the sources and changes of trace elements in the atmosphere,providing a reliable basis for formulating more scientific environmental protection policies.