马学虎

个人信息Personal Information

教授

博士生导师

硕士生导师

性别:男

毕业院校:大连理工大学

学位:博士

所在单位:化工学院

学科:化学工程. 工程热物理

办公地点:化工学院 化工实验楼 D-309

联系方式:辽宁省大连市凌工路2号 大连理工大学化环生学部化工学院 116024

电子邮箱:xuehuma@dlut.edu.cn

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Analysis of atmospheric visibility degradation in early haze based on the nucleation clustering model

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论文类型:期刊论文

发表时间:2021-01-30

发表刊物:ATMOSPHERIC ENVIRONMENT

卷号:193

页面范围:205-213

ISSN号:1352-2310

关键字:Early haze; Initial nucleation process; Heterogeneous cluster; Visible-light absorption

摘要:The initial nucleation of ultrafine particle recently attracts more attention as a key factor in visibility degradation during early haze. In this study, we have performed Density Functional Theory (DFT) calculation to investigate the particle-induced initial nucleation process during early haze. Our calculation results show that the water molecules aggregate surrounding nuclei to form heterogeneous cluster under a certain RH, the synergistic effect of multiple-bonding interactions makes heterogeneous cluster incline to form and stably exist with lower total energy as well as approximately 3-10 times expansionary volume, the hygroscopic growth of aerosol particles would play an important role in affecting the atmospheric visibility. The electron cloud density transferring from the exterior H2O molecule to the interior nuclei in the cluster is characterized by migration effect or nonuniform distribution. The decreasing energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the heterogeneous cluster would lead to a red-shifted absorption wavelength lambda(max). It exerts the blue, indigo and violet visible-light absorption of corresponding wavelength for NO, NO2, NO3- and O-3 heterogeneous clusters to enhance light extinction, thus contributing to visibility degradation, during early haze periods. It helps to intensify the color-enhancing effect of visible light with longer wavelength, such as red, orange as well as yellow light, to promote the evolution of early haze in clean weather period. This study shows that one of the important mechanisms of atmospheric visibility degradation in haze event is the heterogeneous cluster formation in the size range of about 2-4 nm during initial nucleation stage. Our results highlight that prevention of gas-phase chemical species (NO, NO2 and SO2) emission, and also regulatory controls of the concentrations of NO3-, O-3 in atmosphere are necessary to prevent deterioration of the air quality in future.