在线单颗粒气溶胶质谱在大气重金属铅污染事故中的应用研究

Application of On-Line Single Particle Aerosol Mass Spectrometry on Atmospheric Lead Pollution Accidents

重金属铅由于其对人体健康的影响而广受关注。利用在线单颗粒气溶胶质谱仪对2012年发生在华南地区的一次金属铅污染事故中的含铅颗粒物的质谱特征、粒径分布及排放规律进行了分析。监测发现A、B两个监测点位的含铅颗粒物比例多在夜间或凌晨达到高峰,高峰时刻含铅颗粒物数浓度占比最高可达67%,对比广州市区、鹤山超级站的含铅颗粒物浓度占比,可知该地区含铅颗粒物的污染程度较高。两监测点位的含铅颗粒物质谱特征及粒径分布情况非常相似,可能存在相同的排放源或具有相同的形成机制。质谱中都均含有明显的铅、元素碳、硫、硫酸盐等信号,可能来自于燃煤源的排放。通过进一步对比分析燃煤烟气排放的含铅颗粒物质谱特征,判断其为燃煤源排放。

Lead has attracted wide attention because of its impact on human health. The spectral characterist-istics,size distributions and emission behavior of lead-containing particles in a lead pollution accident,which occurred in the southern region of China in 2012 were analyzed by on-line single particle aerosol mass spectrometer. The study found the ratios of lead-containing particles peaked during the nights and early mornings in A and B sites,the highest proportion of leaded-containing particles number concentration could reach 67%. Comparing the proportions of number concentrations of lead-containing particles in urban Guangzhou and Heshan Atmospheric supersite,higher degree of lead-containing particles were found in this area. The spectral characteristics and size distributions of lead-containing particles in these two monitoring sites were very similar,there might be the similar sources or with the same formation mechanism. Obvious elemental carbon,sulfur ions,sulfate and other signals were observed in the mass spectra,which might come from the emissions from coal-fired sources. By further comparative analysis of spectral characteristics of lead-containing particles emitted from coal-fired flue gas,it is concluded that lead-containing particles are mainly from the emissions of coal-fired sources.