Size distribution and chemical composition of secondary organic aerosol formed from Cl-initiated oxidation of toluene

Secondary organic aerosol (SOA) formed from Cl-initiated oxidation of toluene was investigated in a home-made smog chamber. The size distribution and chemical composition of SOA particles were measured using aerodynamic particle sizer spectrometer and the aerosol laser time-of-flight mass spectrometer (ALTOFMS), respectively. According to a large number of single aerosol diameter and mass spectra, the size distribution and chemical composition of SOA were obtained statistically. Experimental results showed that SOA particles created by Cl-initiated oxidation of toluene is predominantly in the form of fine particles, which have diameters less than 2.5 pm (i.e., PM2.5), and glyoxal, benzaldehyde, benzyl alcohol, benzoquinone, benzoic acid, benzyl hydroperoxide and benzyl methyl nitrate are the major products components in the SOA. The possible reaction mechanisms leading to these products are also proposed.

在自制的烟雾箱中对甲苯经氯引发氧化形成的二次有机气溶胶（SOA）进行了研究。分别使用空气动力学粒径谱仪和气溶胶激光飞行时间质谱仪（ALTOFMS）测量了SOA颗粒的粒径分布和化学成分。根据大量单个气溶胶的粒径和质谱数据，对SOA的粒径分布和化学成分进行了统计分析。实验结果表明，甲苯经氯引发氧化产生的SOA颗粒主要以细颗粒形式存在，其直径小于2.5μm（即PM2.5），乙二醛、苯甲醛、苯甲醇、苯醌、苯甲酸、苄基过氧化氢和硝酸苄基甲酯是SOA中的主要产物成分。还提出了产生这些产物的可能反应机理。