基于粒径谱分布的南京市区大气颗粒物来源解析？

Source apportionment of aerosols in urban Nanjing based on particle size distribution

2013年8月8日—2013年8月29日期间,于南京市气象局采用扫描电迁移率粒径谱仪(SMPS)连续监测颗粒物粒径谱分布.运用正交矩阵因子分析法(PMF)分析得出了观测期间气溶胶粒径分布的4个源.结合痕量气体数据(NOx)、气溶胶光吸收系数(Babs781)和颗粒物化学成分(SO2-4、NO-3)确认出4个源,即近处交通排放源、远处交通排放源、混合燃烧排放源和二次气溶胶源.同时基于气象数据(风向和风速),通过条件概率函数(CPF)判断出4个源的方位.近、远处交通源与NOx的日变化规律相似,混合燃烧源与Babs781具有较为一致的变化趋势,而二次气溶胶源与SO2-4和NO-3浓度之和有较好的相关性.4个源的贡献率依次分别为14%、24%、37%和25%,表明混合燃烧排放的相对贡献最大.

The size distribution of aerosols was monitored using SMPS during 2013/8/1—2013/8/29 in urban Nanjing. Through Positive Matrix Factorization （ PMF） analysis, four sources were revealed from the particle size distribution. Combined with the data of trace gases （ NOx ） , aerosol absorption coefficient （ Babs781 ） and chemical composition （ SO2-4 , NO-3 ） , the four sources were identified as adjacent traffic emission,long-distance traffic emission,mix combustion emission, and secondary aerosol, respectively. Meanwhile, based on meteorological data, the directions of the four sources were analyzed using Conditional Probability Functions （CPF）. The results show that Factor 1 and factor 2 had diurnal variations similar to NOx , the trend of variation of Factor 3 was very close to that of Babs781, while Factor 4 was well correlated with the sum of SO2-4 and NO-3 concentrations. The contributions of the four sources were 14%,24%, 37% and 25%,respectively, with the mix combustion emission source being the largest contributor to the particle number concentration.