Modelling Iodine Particle Formation and Growth from Seaweed in a Chamber
Modelling Iodine Particle Formation and Growth from Seaweed in a Chamber
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模拟室内海藻碘颗粒的形成和生长
DOI：
10.1071/en05075
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发表时间：
2005
影响因子：
4.3
通讯作者：
K. Sellegri
中科院分区：
文献类型：
--
作者：
L. Pirjola;C. O’Dowd;Y. Yoon;K. Sellegri
进一步开发了截面大气化学和气溶胶动力学盒模型（AEROFOR），并用于模拟在用无颗粒大气空气冲洗的室中海藻的超细颗粒形成和生长。在该模型中，热力学稳定的簇是由 OIO 蒸气的二聚体成核形成的，其前体被假定为海藻释放的分子 I2。考虑了颗粒的分形几何形状。对于(0.5-1.5) × 10 9 cm -3 s -1 的I2通量，模型预测强粒子爆发，I2蒸气和大于3 nm的粒子的稳态浓度分别高达4 × 10 9 -1.2 × 10 10 cm -3 和5.0 × 10 6 -9.2 × 10 6 cm -3 。在不到 150 秒内达到稳定状态，并且 3-6 nm 颗粒的预测生长速率在 1.2-3.6 nm min -1 范围内变化。讨论了尺寸分布对 I2O3 团簇形成、额外可凝蒸气、OIO 蒸气光解速率以及 (OIO)n 团簇密度的敏感性。模拟结果与 2003 年 9 月在爱尔兰梅斯海德举行的 BIOFLUX 活动期间进行的室测量非常一致，证实 I2 排放和碘氧化物成核可以在很大程度上解释沿海成核现象。
A sectional atmospheric chemistry and aerosol dynamics box model (AEROFOR) was further devel- oped and used to simulate ultra-fine particle formation and growth from seaweed in a chamber flushed with particle-free atmospheric air. In the model, thermodynamically stable clusters were formed by dimer nucleation of OIO vapour, whose precursor was assumed to be molecular I2 emitted by seaweed. Fractal geometry of particles was taken into account. For the I2 fluxes of (0.5-1.5) × 10 9 cm −3 s −1 the model predicted strong particle bursts, the steady state concentrations of I2 vapour and particles larger than 3 nm were as high as 4 × 10 9 −1.2 × 10 10 cm −3 and 5.0 × 10 6 -9.2 × 10 6 cm −3 respectively. The steady state was reached in less than 150 s and the predicted growth rates of 3-6 nm particles varied in the range of 1.2-3.6 nm min −1 . Sensitivity of the size distribution against I2O3 cluster formation, an extra condensable vapour, the photolysis rate of the OIO vapour as well as against the density of (OIO)n-clusters was discussed. The modelled results were in good agreement with the chamber measurements performed during the BIOFLUX campaign in September, 2003, in Mace Head, Ireland, confirming that I2 emissions and nucleation of iodine oxides can largely explain the coastal nucleation phenomenon.