The role of low volatile organics on secondary organic aerosol formation
The role of low volatile organics on secondary organic aerosol formation
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DOI：
10.5194/acp-14-1689-2014
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发表时间：
2013-06
影响因子：
6.3
通讯作者：
H. Kokkola;P. Yli-Pirilä;M. Vesterinen;H. Korhonen;H. Keskinen;S. Romakkaniemi;L. Hao;A. Kortelainen;J. Joutsensaari;D. Worsnop;A. Virtanen;K. Lehtinen
中科院分区：
文献类型：
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作者：
H. Kokkola;P. Yli-Pirilä;M. Vesterinen;H. Korhonen;H. Keskinen;S. Romakkaniemi;L. Hao;A. Kortelainen;J. Joutsensaari;D. Worsnop;A. Virtanen;K. Lehtinen
抽象的。大尺度大气模型通常以室内实验为基础描述二次有机气溶胶(SOA)的形成，它们往往系统性地低估了观测到的有机气溶胶负荷。由于大气层气溶胶是大气气溶胶的重要组成部分，这种差异导致对大气层气溶胶辐射强迫的贡献被低估。在这里，我们表明，被低估的SOA产量可以部分解释为在室内实验中形成化合物的SOA的壁面损失。我们提出了一种室内实验，其中α-Pinene和臭氧被注入到特氟龙室中。当这两种化合物反应时，我们观察到新粒子的快速形成和生长。对这一形成和生长事件的理论分析表明，在燃烧室中迅速形成了挥发性很低的氧化挥发性有机化合物(OVOC)。如果这些被氧化的有机化合物在气相中形成，它们的壁面损失将对它们在气相和颗粒相之间的分配产生重大影响。虽然这些挥发性极低的OVOCs有助于新颗粒的生长，但在实验过程中，它们的质量将几乎完全耗尽到腔壁，而挥发度较高的OVOCs的耗尽效率较低。根据我们的模型模拟，OVOC对新粒子形成事件的贡献可能在10−5μg m−3量级。
Abstract. Large-scale atmospheric models, which typically describe secondary organic aerosol (SOA) formation based on chamber experiments, tend to systematically underestimate observed organic aerosol burdens. Since SOA constitutes a significant fraction of atmospheric aerosol, this discrepancy translates into an underestimation of SOA contribution to radiative forcing of atmospheric aerosol. Here we show that the underestimation of SOA yields can be partly explained by wall losses of SOA forming compounds during chamber experiments. We present a chamber experiment where α-pinene and ozone are injected into a Teflon chamber. When these two compounds react, we observe rapid formation and growth of new particles. Theoretical analysis of this formation and growth event indicates rapid formation of oxidized volatile organic compounds (OVOC) of very low volatility in the chamber. If these oxidized organic compounds form in the gas phase, their wall losses will have significant implications on their partitioning between the gas and particle phase. Although these OVOCs of very low volatility contribute to the growth of new particles, their mass will almost completely be depleted to the chamber walls during the experiment, while the depletion of OVOCs of higher volatilities is less efficient. According to our model simulations, the volatilities of OVOC contributing to the new particle formation event can be of the order of 10−5 μg m−3.