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Recent Insights into the Formation and Chemical Composition of Atmospheric Nanoparticles from the Aerosol Nucleation and Realtime Characterization Experiment


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.......

【作者名称】: J. N. Smith, K. F. Moore, F. L. Eisele, A. K. Ghimire, H. Sakurai, P. H. McMurry
【作者单位】: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80305
【关 键 词】: Recent Insights into the Formation and Chemical Composition of Atmospheric Nanoparticles from the Aerosol Nucleation and Realtime Characterization Experiment
【会议名称】: ACS Symposium Series 890; Symposium on Nanotechnology and the Environment: Applications and Implications; ;
【期刊论文数据库】: [DBS_Articles_01]
【期刊论文编号】: 101,777,765
【摘要长度】: 2,795
【会议组织】: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80305
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