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首页> 外文会议>ACS Symposium Series 890; Symposium on Nanotechnology and the Environment: Applications and Implications; ; >Recent Insights into the Formation and Chemical Composition of Atmospheric Nanoparticles from the Aerosol Nucleation and Realtime Characterization Experiment
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Recent Insights into the Formation and Chemical Composition of Atmospheric Nanoparticles from the Aerosol Nucleation and Realtime Characterization Experiment

机译：气溶胶成核和实时表征实验对大气纳米颗粒形成和化学组成的最新见解

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Recent atmospheric observations have provided important insights into conditions that lead to new particle formation from gas phase precursors, or nucleation. Nucleation sometimes follows regular diurnal patterns, with peak particle production rates occurring in midday when solar radiation is most intense1. Nucleation can also occur in response to atmospheric perturbations, such as the removal of pre-existing aerosol by cloud processin2 or the addition of gas phase reactants from a surface source3, but almost always occurs during daylight hours. Nucleation has been observed on mountains4, in the boreal forests of Finland5, in polluted urban centers6, and in the marine boundary layer7. Impactor measurements of freshly nucleated aerosol in a Finnish boreal forest suggest that these particles are enriched with dimethyl amine8, while other measurements in a variety of locations suggest an important role for sulfuric acid vapor9. Another interesting observation is that the appearance of new particles is sometimes preceded by the continuous growth of ions from small sizes (mobilities between 3.2 and 0.32 cm2V-1s-1 corresponding to diameters between 0.4 and 2.5 nm) up to large sizes (mobilities as low as 0.01 cm2V-1s-1 corresponding to a 50 nm diameter panicle) 10. While nucleation under a wide range of circumstances is now well documented, we do not yet have accurate models for predicting nucleation rates. Observed rates are occasionally consistent with the predictions of the binary theory of sulfuric acid and water11, but rates of panicle formation are often orders of magnitude higher than can be explained by binary theory 12. A ternary process involving sulfuric acid, water, and ammonia 13 (or possible an organic compound such as an amine) may explain these high rates of particle production, but additional atmospheric observations are needed to verify this. Theories exist that describe nucleation on ion centers (ion induced nucleation) 14, yet there have been no measurements of the composition of atmospheric ions during nucleation events to validate these. The Aerosol Nucleation and Realtime Characterization Experiment (ANARChE), was a multi-investigator study that focused primarily on understanding the nucleation and growth of atmospheric aerosols. The study took place in midtown Atlanta, GA, from July 22 to September 4, 2002. This site was chosen because three years of continuous measurements at this site have shown that nucleation occurs regularly in August6. ANARChE brought together, for the first time, gas phase measurements of important precursors to new particle formation with several unique instruments for studying the composition of nanoparticles and ambient ions. We present below a review of the most important observations from this study.
机译：最近的大气观测为导致气相前驱物形成新颗粒或成核的条件提供了重要见识。成核有时遵循规律的昼夜模式，在太阳辐射最强烈的正午1出现峰值粒子生产率。成核也可能是由于大气扰动而发生的，例如通过云处理2清除已存在的气溶胶2或从表面源3添加气相反应物3，但几乎总是在白天进行。在山脉4，芬兰的北方森林5，污染的城市中心6以及海洋边界层7都观察到了成核现象。芬兰北方森林中新鲜成核气溶胶的撞击器测量结果表明，这些颗粒中富含二甲基胺8，而其他位置的其他测量结果也表明，硫酸蒸汽具有重要作用9。另一个有趣的观察结果是，有时在新粒子出现之前，离子会从小尺寸（迁移率介于3.2至0.32 cm2V-1s-1之间，对应于直径介于0.4至2.5 nm之间）连续增长，直至大尺寸（迁移率低至（0.01 cm2V-1s-1对应于直径为50 nm的圆锥花序）。10.虽然目前已经广泛记录了成核条件下的成核现象，但我们尚没有用于预测成核速率的准确模型。有时观察到的速率与硫酸和水的二元理论的预测相一致11，但是穗形成的速率通常比二元理论12所解释的高几个数量级。涉及硫酸，水和氨的三元过程13 （或可能的有机化合物，例如胺）可以解释这些高的颗粒产生速率，但是需要其他大气观测来验证这一点。存在描述离子中心上的成核（离子诱导的成核）14的理论，但是还没有测量成核过程中大气离子的组成的量度来验证这些。气溶胶成核和实时表征实验（ANARChE）是一项多研究者研究，主要致力于了解大气气溶胶的成核和生长。该研究于2002年7月22日至9月4日在佐治亚州亚特兰大市中心地区进行。之所以选择该站点，是因为对该站点进行了连续三年的测量，结果显示成核在8月6日定期发生。 ANARChE首次使用几种独特的仪器来研究新颗粒形成的重要前体的气相测量，以研究纳米颗粒和环境离子的组成。我们在下面介绍了这项研究中最重要的观察结果。

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