Geoscience Reference
In-Depth Information
The expressions for the ion density profile n.r/ and the ion flux
J
in
r
,
E
,
L
variables are as follows:
Z
dE
Z
m
2
r
X
s
dL
2
p
L
2
.r/
L
2
f
s
.r;E;L/
n.r/
D
(3.28)
and
s
Z
dE
Z
dL
2
f
s
.r;E;L/:
m
3
X
s
4
2
J
D
(3.29)
The ion flux is independent of
r
.
The boundary conditions to the kinetic equation should be formulated individu-
ally for each concrete case.
3.3
Condensation
Trace gases are commonly recognized to react actively with the aerosol component
of the Earth's atmosphere. Substantial changes to atmospheric chemical cycles
resulting from the presence of aerosol particles in the atmosphere make us look more
attentively at the nature of the processes depending on the activity of the atmospheric
aerosols (Seinfeld and Pandis
2006
). The processes of gas-particle interactions are
usually the first-order chemical reactions going along the route:
.A/
C
.P/
!
.AP/;
(3.30)
where (A), (P), and (AP) stand, respectively, for a reactant molecule, an aerosol
particle, and the final product resulting from the reaction Eq.
3.30
.
As an example we refer to ozone, a key substance for the Earth atmosphere
protecting living systems on our planet against the sun UV radiation. Since the
discovery of the ozone hole in the mid-1970s (Farman et al.
1985
), it has been well
established that ozone is subject to periodical large depletion events at the Poles
and to continuous decay in the global stratosphere. The amplitudes of ozone level
variations are partly driven by heterochemical reactions occurring on the surfaces of
polar stratosphere cloud particles that transform the stable reservoir molecules into
radical precursors (see Lohman and Feichter
2005
and references therein). Processes
such as Eq.
3.30
are also of importance in the aerosol catalysis (Weber et al.
1999
;
Feng et al.
2001
).
The interconnection between uptake and mass accommodation efficiencies was
studied by several groups (Kulmala and Wagner
2001
; Finlayson-Pitts and Pitts
2000
; Davidovits et al.
1991
,
1995
; Natanson et al.
1996
; Laaksonen et al.
2005
;
Davis
1983
; Shi and Seinfeld
1991
; Zagaynov et al.
1976
). The condensational
