Sensitivities of the absorptive partitioning model of secondary organic aerosol formation to the inclusion of water
Sensitivities of the absorptive partitioning model of secondary organic aerosol formation to the inclusion of water
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DOI：
10.5194/acp-9-2919-2009
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发表时间：
2008-12
影响因子：
6.3
通讯作者：
M. Barley;D. Topping;M. Jenkin;G. Mcfiggans
中科院分区：
文献类型：
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作者：
M. Barley;D. Topping;M. Jenkin;G. Mcfiggans
半挥发性有机组分的预测分布之间的气相和冷凝相作为环境相对湿度的函数和所使用的分配模型的具体形式进行了研究。一个基于摩尔分数的模型，修改，以便不使用摩尔质量在计算中，被发现预测相同的RH依赖性的组分分配的传统质量为基础的分配模型，使用摩尔质量平均根据在凝聚相的摩尔数预测。最近报道的第三个版本的分区模型，使用单个组件的摩尔质量被证明给其他两个模型显着不同的结果。进一步的敏感性，假设预先存在的颗粒负荷和参数化的有机成分的非理想性进行了探讨，并显着的贡献，cantly预测的二次有机颗粒负荷的变化。是水蒸气可能与环境气溶胶相互作用的许多可能方式。环境相对湿度将直接决定亚饱和潮湿大气中平衡水含量和气溶胶粒子的大小。Swietlicki等人（2008年）对这种吸湿性进行了广泛研究，并对大气测量进行了审查。当粒子遇到过饱和时，云滴可能在那些在当时条件下能够表现为云凝结核的粒子上成核和生长。影响这种气溶胶“活化”的性质已在McFiggans等人（2006）中总结。类似地，当将空气团暴露于适当的温度状态和相关的冰过饱和时，表现为冰核的气溶胶颗粒上的冰晶成核，或先前已激活为液滴的气溶胶的冻结可能会发生。这种行为已被审查，
The predicted distribution of semi-volatile organic components between the gaseous and condensed phase as a function of ambient relative humidity and the specific form of the partitioning model used has been investigated. A mole fraction based model, modified so as not to use molar mass in the calculation, was found to predict identical RH depen- dence of component partitioning to that predicted by the con- ventional mass-based partitioning model which uses a mo- lar mass averaged according to the number of moles in the condensed phase. A recently reported third version of the partitioning model using individual component molar masses was shown to give significantly different results to the other two models. Further sensitivities to an assumed pre-existing particulate loading and to parameterised organic component non-ideality are explored and shown to contribute signifi- cantly to the variation in predicted secondary organic par- ticulate loading. are a number of possible means by which water vapour may interact with the ambient aerosol. Ambient relative humidity will directly determine the equilibrium water content and size of aerosol particles in the sub-saturated moist atmosphere. This hygroscopicity has been widely investigated and atmo- spheric measurements reviewed in Swietlicki et al. (2008). As particles encounter supersaturation, cloud droplets may nucleate and grow on those which are able to behave as cloud condensation nuclei under the prevailing conditions. Properties affecting such aerosol "activation" have been sum- marised in McFiggans et al. (2006). Similarly, nucleation of ice crystals on aerosol particles behaving as ice nuclei, or freezing of aerosol that had previously activated into liquid droplets may occur when exposing an air parcel to the ap- propriate temperature regime and associated supersaturation with respect to ice. Such behaviour has been reviewed by