Equilibrium Composition of Aerosol Particles

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Equilibrium Composition of Aerosol Particles
Equilibrium What are xX, xY, and xZ?
Some time scale
Z
X
New particle
Y
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Ideal and Non-Ideal Behavoir of Solutions
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Question
Consider an air parcel at T 300 K and 30 RH
with 20 ppb HNO3 and 20 ppb NH3 in the gas-phase.
Will NH4NO3 particles form? If so, what is the
NH4NO3 aerosol mass concentration if no other
particulate matter exists? Assume only solid
particles (no aqueous solutions).
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Deliquescence Efflorescence of a Single
Component System (NaCl)
efflorescence
deliquescence
Tang, JGR-D 1997
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Free Energy of Deliquescence - Efflorescence
Gibbs Free Energy
RH
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Evolution of Water Activity in Atmospheric
Particle
Often requires knowledge of RH-histroy
RHgt80
RHlt40
RH70
RH80
Ocean
Land
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Deliquesence-Efflorescence of Complex Compositions
Lightstone, et al. JPC 2000
Schlenker, et al. JPC 2005
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Kelvin Effect Physical Cartoon
Equilibrium vapor pressure is higher over a
curved surface than a flat one. Important for
nucleation of new particles, lifetime of small
droplets.