0.95
10 −1
10
0
10
1
10
2
10 −1
10 0
10 1
10 2
0.96
0.97
0.98
0.99
1
1.001
1.002
1.003
1.004
1.005
−0.04
−0.02.
0
0.02
Kelvin term
Raoult term
Total
0.04
0.06
S c
r c
Droplet Diameter μm
Saturation Ratio
50 nm (NH 4 ) 2 SO 4
100 nm (NH 4 ) 2 SO 4
200 nm (NH 4 ) 2 SO 4
200 nm (NH 4 ) 2 SO 4 , 50% insol
50 nm NaCl
100 nm NaCl
200 nm NaCl
200 nm NaCl, 50% insol
wet droplet radius, r,μm
Supersaturation % = 100 (S−1)
Aerosol in Global Atmosphere, Fig. 13 Top: The Kőhler equation can be envisaged as the competition between
the curvature (Kelvin) and solute (Raoult) terms. Bottom:
Activation curves for a range of dry diameter of salt
((NH 4 ) 2 SO 4 – solid, NaCl – dashed) particles (red, green
and blue curves) and for 200 nm particles containing 50%
by mass insoluble core (magenta). (Copyright European
Geophysical Union 2006. Reprinted from [73])
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Aerosol in Global Atmosphere