利用SPAMS研究南宁市冬季单颗粒气溶胶化学成分

Chemical Composition of the Single Particle Aerosol in Winter in Nanning Using SPAMS

利用单颗粒气溶胶飞行时间质谱仪（SPAMS）对南宁市2015年冬季2月15~24日期间大气PM2.5进行观测.SPAMS所测得大气PM2.5数浓度与PM2.5质量浓度线性相关系数为0.76,在一定程度上颗粒物数浓度可反映大气污染状况.利用自适应共振神经网络分类方法（Art-2a）对PM2.5化学成分进行分类,确定PM2.5化学成分主要为元素碳、有机元素碳混合颗粒、有机碳、富钾颗粒、矿物质、富钠颗粒、二次无机颗粒、左旋葡聚糖以及其它重金属共9类.成分占比最高的是元素碳,其次是有机碳和富钾颗粒.监测到80%以上的PM2.5粒径主要集中在0.2~1.0μm之间,峰值出现在0.62μm处,各化学成分的粒径分布特征与总颗粒数粒径分布特征相似.各化学成分数浓度与PM2.5质量浓度随时间变化趋势较一致,化学成分数浓度占比变化在一定程度上可反映瞬时的污染来源.

Single Particle Aerosol Mass Spectrometry（ SPAMS） was performed to characterize the PM2. 5in Nanning from 15 to 24 February 2015. The correlation（ R2） between the PM2. 5number concentration and the mass concentration of PM2. 5obtained using SPAMS was 0. 76. The particle number concentration could reflect the atmospheric pollution situation to some degree. The Art-2a classification method was used to classify the chemical composition of PM2. 5. The results showed that the principal chemical constituents were elemental carbon,organic elements carbon hybrid particles,organic carbon,rich potassium particles,mineral substance,rich sodium particles,second inorganic particles,levoglucosan and other heavy metals. Among them,the composition of elemental carbon was the highest,followed by organic carbon and rich potassium particles. The particle size of 80% of PM2. 5was mainly concentrated in the range of 0. 2 μm to 1. 0 μm with a peak value occurring at 0. 62 μm. The particle size distribution characteristics of different chemical components were similar. The number concentration of the chemical components in PM2. 5had the same variation tread with the mass concentration of PM2. 5over time. To a certain extent,the change in chemical composition could reflect the instantaneous pollution source.