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Nucleation rate of particles in the lower atmosphere: Estimated time needed to reach pseudo‐steady state and sensitivity to H 2 SO 4 gas concentration
Author(s) -
Yu Fangqun
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017084
Subject(s) - nucleation , steady state (chemistry) , thermodynamics , ternary operation , sensitivity (control systems) , sulfuric acid , kinetic energy , homogeneous , reaction rate constant , kinetics , chemistry , materials science , physics , inorganic chemistry , quantum mechanics , programming language , electronic engineering , computer science , engineering
Using a kinetic model, we estimate the time‐needed ( t 0 ) to establish a pseudo‐steady state nucleation when sulfuric acid concentration ([H 2 SO 4 ]) suddenly increases to a certain fixed level. We find that t 0 is roughly inversely proportional to [H 2 SO 4 ]. The assumption of instantaneously achieved pseudo‐steady state concentration of critical clusters, on which the classical nucleation theories are based, is no longer valid when t 0 is longer than the time period that [H 2 SO 4 ] can be treated as constant. Under the lower marine atmospheric conditions considered in this study, the nucleation rate predicted by ion‐mediated nucleation theory is very sensitive to [H 2 SO 4 ] when [H 2 SO 4 ] is low (<∼7 × 10 6 /cm 3 ) but such a sensitivity reduces significantly as [H 2 SO 4 ] increases, which is quite different from that predicted with classical binary and ternary homogeneous nucleation theories.