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Detailed Reference Information |
Pirjola, L., Korhonen, H. and Kulmala, M. (2002). Condensation/evaporation of insoluble organic vapor as functions of source rate and saturation vapor pressure. Journal of Geophysical Research 107: doi: 10.1029/2001JD001228. issn: 0148-0227. |
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Condensation growth of atmospheric particles by insoluble organic vapors was studied by a monodisperse aerosol dynamics model MONO32 including atmospheric chemistry mechanism. The source rate of the vapor and its saturation vapor density at a particle surface were varied. The initial particle number size distribution was assumed to be bimodal, and aerosol was initially an internal mixture of particles consisting of soluble sulphuric acid and insoluble organic material in a ratio of 1:1. Model simulations predicted that if the ratio of the vapor source rate and the condensation sink of particles, Q/CS, exceeded 108 cm-3 and the vapor was nonvolatile or low volatile, the 10 nm nuclei grew with the growth rates of 2.5--3 nm h-1 and could act as cloud condensation nuclei in supersaturations of 1.6% or lower after 24 h simulation. Then the vapors must have saturation vapor pressures less than 7 ¿ 106 cm-3. However, the higher the ratio of Q/CS, the higher the saturation vapor pressure could be. When the vapor was highly volatile, i.e., the saturation vapor density was high enough, in our simulations greater than 6 ¿ 107 cm-3 the Ostwald ripening was observed. Then the nucleation mode particles were not able to grow but coagulated with larger particles without causing any significant impact on climate. An analytical expression for the saturation vapor density for the Ostwald ripening (cOst) was derived as a function of the ratio of Q/CS. Sensitivity tests for the accommodation coefficient and thermodynamic parameters as well as their effects on cOst were investigated. |
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Abstract |
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Keywords
Atmospheric Composition and Structure, Aerosols and particles (0345, 4801), Atmospheric Composition and Structure, Troposphere--composition and chemistry |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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