Relating hygroscopicity and composition of organic aerosol particulate matter
Relating hygroscopicity and composition of organic aerosol particulate matter
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DOI：
10.5194/acp-11-1155-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Baltensperger, U.
中科院分区：
文献类型：
--
作者：
Duplissy, J.;DeCarlo, P. F.;Baltensperger, U.
采用吸湿性串联微分迁移率分析仪（HTDMA）对烟雾室内有机前体物化学和光化学氧化过程中形成的二次有机气溶胶（SOA）的吸水性进行了测量。用气溶胶质谱仪（AMS）同时测定了非难降解亚微米气溶胶的电子电离质谱，并研究了两种不同信号之间的相关性。发现SOA吸湿性与表示为总有机信号的分数的离子信号m/z 44的相对丰度（f（44））强烈相关。m/z 44主要是由于所有类型的SOA系统研究的离子碎片CO2+，并已被证明与环境和室OA的有机O/C强烈相关。还对来自偏远地点少女峰-乔赫和大城市墨西哥城的两个现场实验的环境OA进行了分析，在那里发现了类似的结果。在亚饱和RH下OA的吸湿性之间的简单经验线性关系，如由吸湿生长因子（GF）或“kappa（org）"参数给出的，并且f（44）由kappa（org）= 2.2 × f（44）-0.13确定。随着AMS和HTDMA测量数据库在世界各地不断扩大，这种近似值可以得到进一步验证和改进。由于f（44）与气团的光化学年龄相关，因此使用这种近似值可以在大气模式中对OA的吸湿性参数化进行重要简化。
A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f(44)). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfrau-joch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "kappa(org)", parameter, and f(44) was determined and is given by kappa(org) = 2.2 x f(44) - 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f(44) is correlated with the photochemical age of an air mass.