成都市夏冬季大气胺颗粒物的单颗粒质谱研究

基于单颗粒气溶胶质谱（SPAMS）对成都市夏冬两季大气胺颗粒进行了综合观测，结合ART-2a算法及人工合并，2个季节大气中的胺颗粒都可分为7类，各类颗粒贡献的季节差异明显，燃烧源颗粒（如EC）在夏季贡献较大，而老化的有机碳颗粒（OCa）贡献在冬季显著升高.两季节平均质谱差减进一步证明夏、冬季分别以燃烧源和老化的胺颗粒为主.因高温分解，夏季胺颗粒占比在正午出现明显的低值，而下午的燃烧活动（如生物质燃烧）对该占比提升作用明显；冬季胺颗粒占比在白天显著高于夜间.随污染加重，胺颗粒数在夏冬两季均快速增加，其中夏季EC颗粒升高最为明显，污染最重时贡献可达47%；冬季升高最明显的是老化程度更高的OCa颗粒，当PM_2.5浓度达到200μg/m³以上时，其贡献比例可达37%.因此，由于污染源和气候条件的差异，成都市大气胺颗粒形成机制和理化特征季节差异巨大.

Single-particle characterization of amine-containing particles during summer and winter in Chengdu

A single particle aerosol mass spectrometer (SPAMS) was deployed in urban Chengdu to analyze atmospheric amine-containing particles during summer and winter. Seven major single particle types were resolved with the ART-2a algorithm and manual merging, and their contribution to the total amine-containing particles presented obviously seasonal difference with particles from burning sources (such as EC particles) exhibiting high contribution in summer while aged organic particles (OCa) in winter. The analysis on the differential mass spectrum between two seasons confirmed that the particles from burning sources and the aged particles dominated amine-containing particles in summer and winter, respectively. In summer, the proportion of amine-containing particles showed low values at noon due to decomposition under high temperature, and increased obviously in the afternoon as a result of biomass burning. However, the proportion of amine-containing particles in daytime was higher than that at night in winter. With the aggravation of pollution, the number of amine-containing particles increased rapidly in the two seasons. EC particles increased most in summer and accounted for 47% of the total amine-containing particles when pollution was most serious. While in winter, the contribution of aged OCa particles increased significantly, reaching 37% when PM_2.5 was higher than 200μg/m³. Therefore, the formation mechanisms and physicochemical characteristics of amine-containing particles in Chengdu are greatly different between seasons due to the variations in sources and climatic conditions.