The effects of size-resolved mineralogical composition
on heterogeneous chemistry on dust particle surfaces
Advisor: Prof. Irina N. Sokolik
Gill-Ran Jeong
The 4th Earth and Atmospheric Sciences Graduate Symposium, November 10th, 2006
The roles of dust aerosols in atmospheric chemistry
Chemical effect
O3, SO2, NO2, HNO3
Radiative effect
Dust properties
Direct impact
Radiative
radiative forcing at TOA
radiative forcing at the sfc
heating/cooling
actinic flux
Chemical
heterogeneous chemistry
on dust surface
Indirect impact
photolysis
The role of heterogeneous reaction on dust aerosols
in the chemistry-climate system
•Size
•Composition
•Shape
•Mixing with other aerosols
such as BC, OC, sulfate,
nitrate, and sea-salt
O3
SO2
NO2
HNO3
Dust properties
Direct impact
Indirect impact
Radiative
radiative forcing at TOA
radiative forcing at the sfc
heating/cooling
actinic flux
cloud properties
heterogeneous chemistry
on dust surface
photolysis
Chemical
Hygroscopic
CCN
Limitations of past studies and motivation of this study
•
•
•
•
 Size distributions
commonly-known dust size distributions,
a single mode size distribution,
a few size bins [D’Almeida, 1987; Jaenicke et al., 1993; Kopke et al., 1997; Zhang
et al., 1999; Liao et al., 2003; Bian and Zender, 2003; Tang et al., 2004; Bauer et
al., 2004, 2005; Martin et al., 2003].
•
•
 Uptake coefficients
one uptake coefficient of a particular chemical element or mineral species based
on laboratory measurement and modeling [Bauer et al., 2004, 2005; Zhang and
Carmichael, 1999; Dentener et al., 1996; Bian and Zender, 2003; Martin et al.,
2002, 2003; Liao et al., 2003, 2004; Usher et a;., 2002].
•
•
 A mixture of mineralogy of dust
Because the mineralogy of dust particles varies even though the similar chemical
elements consist of dusts [Berry et al., 1983; Anthony ]
The abundance of minerals also varies with dust source region or transportation
or aging of dust [Glaccum and Prospero, 1980].
•
The importance of size and compositions of mineral dust in modeling and
measurement study. (Usher et al., 2002).
Therefore, we need to construct size-resolved mineral composition of
dust aerosols in order to investigate the effects of dust size
distribution and compositions on the heterogeneous loss rates.
Objectives
1. To construct size-resolved mineralogical composition of dust particles
by selecting the range of mass fraction of the three main mineralogical compositions,
particularly considering the alkalinity from carbonate-containing species and iron oxide
contents in clay aggregates, pursuing consistent treatment of mineral dust aerosols in
both chemistry and radioactive modeling.
2. To calculate heterogeneous loss rates on dust particles by integrating
a gas-to-particle diffusion rate constant using the Fuchs-Sutugin approximation
in the transition regime. The recent data on uptake coefficients of individual minerals
and authentic dust and several dust size distributions reported from field and
laboratory experiments were used.
Goals of this study
To investigate how size and mineralogical compositions of dust affect
heterogeneous loss rates (khet) of gaseous species on particle surfaces and
implication for the tropospheric photochemistry.
Approach
kj 
Mass transfer on dust particles and chemical properties of dust particles
r2
 F(r, γ )n(r)dr
j
r1
O3, SO2, NO2, HNO3
1. Alkalinity  Uptake acidic gases
2. Adsorption:
4rD jV
SO2 (g)+ O2-  SO32F (r ,  ) 
SO2 (g)+ OH-  HSO31  Kn f (Kn , j )
3. Oxidation:
SO32-(a)+ O3(g) SO42-(a)+ O2(g)
HSO3-(a)+ O3(g) HSO4-(a)+ O2(g)
4. Solubility
2HNO3 + CaCO3 
Ca(NO3)2 + H2O + CO2
(Krueger et al., 2003)
changes in morphology, solubility,
scattering
Ni
(log r  log Ri )2
3
dN
n(log r ) 
 
exp[
]
2
d log r i 1 log  2
2
(log

)
i
i
Approach
The overall heterogeneous loss rates of a gaseous species j, kj
O3 dust
 1.5O2
L
kj   kp,j
p 1
L is the number of types of mineral
compounds.
kp,j is the overall heterogeneous loss
rate of gaseous species j
on the surface of material compound p
SO2 dust
 sulfate
NO2 dust
 0.5nitrite  0.5nitrate
HNO3 dust

 nitrate
r2
kp, j   F(r,γ p.j )n p (r)dr
r1
γp,j, : uptake coefficient of gaseous species j
by mineral compound p
np(r) is the size distribution of mineral
compound p
F(r, γp,j) is mass transfer coefficient
whereby the Fuchs-Sutugin
approximation is applied to
the gas-to-particle diffusion in the
transition regime.
Iron-oxide clay aggregates
Calcite (carbonate-containing
minerals)
Quartz: a non-absorbing and
inactive mineral of gaseous uptake.
Approach
Type of size-resolved mineral composition of dust aerosols
1) Composition
(uptake coefficient)
REF (reference dust)
2) Size distribution
3) Mass fraction of
mineralogical species
BULK (bulk dust)
4) Mass partitioning of
mineralogical species
in fine and coarse modes
1 2 3 4
REF (khet_ref)
X X
BULK (khet_bulk)
X X X
FAC (khet_fac )
X X X X
FAC (fine and coarse dust)
1) Uptake coefficients by main mineralogical compositions
Table 1. Uptake coefficients
(a )O3 dust
 1.5O2
Mineral species or
alternative
chemical elements
Kaolinite
γ
References
3.0 ± 1.0 × 10-5
Hanisch and Crowley, 2003
(Atmos. Chem. Phys.)
Dentener et al., 1996 refer to Garland,
1974 usnig deposition velocity,
γ = 4υdep/c
Mitchel et al., 2002 (GRL)
Mitchel et al., 2002 (GRL)
Michel et al., 2003 (Atmos. Environ)
Mitchel et al., 2002 (GRL)
Michel et al., 2003 (Atmos. Environ)
Calcite
1.0E-5 ~ 2.0E-4
(5.0 x 10-5) best guess
SiO2
Saharan sand
5.0 ± 3.0 × 10-5
6.0 ± 3.0 × 10-5
Chinese loess
2.7 ± 0.9 × 10-5
(b ) SO2 dust
 sulfate
Three main
mineral groups
Mineral species or
Alternative
chemical elements
Clay aggregates
Kaolinite
Illite
Montrollinite
α-Al2O3
α-Fe2O3
Calcite
Calcite
Dolomite
CaCO3
CaO
MgO
Quartz
SiO2
Authentic dust
α-Al2O3
α-Al2O3
CaCO3
SiO2
Saharan dust
Chinese loess
-4
1.6 ± 0.5 x 10
9.5 ± 0.3 x 10-5
~ 1.0 x 10-4
1.4 ± 0.7 x 10-4
< 1 x 10-7
(3.9~4.6) x 10-3
(4.1~5.0) x 10-7
3.0 ± 1 x 10-5
Usher et al., 2002 (JGR)
Goodman et al., 2001 (J. Phys. Chem.)
Usher et al., 2002 (JGR)
Usher et al., 2002 (JGR)
Ullerstam et al., 2002 (Phys. Che.
Chem. Phys.)
Usher et al., 2002 (JGR)
1) Uptake coefficients by main mineralogical compositions
Table 1. Uptake coefficients
(c ) NO2 dust
 0.5nitrite  0.5nitrate
Mineral species
or alternative
chemical elements
α-Al2O3
CaO
SiO2
Saharan dust
Chinese loess
γ
9.1 x 10-6
8.5 x 10-5
2.2x10-5
5.4 x 10-5
Too low (4.0x10-10)
RG*1.0 x 10-6
~ 2.0 x 10-5
2.1 x 10-6
4.4 x 10-5
Three main
mineral groups
Mineral species or
Alternative
chemical elements
Clay aggregates
Kaolinite
Illite
Montrollinite
α-Al2O3
α-Fe2O3
Calcite
Calcite
Dolomite
CaCO3
CaO
MgO
Quartz
SiO2
References
Underwood et al., 2001 (JGR)
Underwood et al., 2001 (JGR)
Underwood et al., 2001 (JGR)
Underwood et al., 2001 (JGR)
Underwood et al., 2001 (JGR)
Authentic dust
(d ) HNO3  nitrate
dust
Kaolinite
(11 ± 1.6) x10-2
CaCO3
(18 ± 4.5) x 10-2
SiO2
Saharan sand
(2.9 ± 0.2) x 10-5
1.36x10-1
Chinese loess
1.71x10-1
Hanisch and Crowley, 2001 (Phys.
Chem.Chem.Phys.)
Hanish and Crowley, 2001 (J. Phys.
Chem.)v
Underwood et al., 2001 (JPC)
Hanisch and Crowley, 2001 (Phys.
Chem.Chem.Phys.)
Hanisch and Crowley, 2001 (Phys.
Chem.Chem.Phys.)
2) Dust size distribution
Table 2. dust size distribution
Dust Size Distribution
/ Reference
C04
Clarke et al. [2004]
Size mode
D87
D’Almeida [1987]
rg m)
σg
Mass fraction
GMD
SMD
MMD
O98
Hess et al. [1998]
rg m)
σg
Mass fraction
GMD
SMD
MMD
B02
Dubovik et al. [2002]
rg m)
σg
Mass fraction
GMD
SMD
MMD
2.5μm of SMD
Mode1
rg m)
σg
Mass fraction
GMD
SMD
MMD
0.08
2.1
1.00%
0.16
0.48
0.83
0.07
1.95
3.40%
0.14
0.34
0.53
0.088
1.52
9.10%
0.18
0.25
0.30
Mode2
Mode3
0.345
1.46
1.80%
0.69
0.92
1.06
0.885
1.85
69.40%
1.77
3.77
5.51
0.70
1.9
95.30%
1.40
3.19
4.82
0.39
2.00
76.10%
0.78
2.04
3.30
Mode4
Mode5
4.335
1.5
28.80%
8.67
12.05
14.20
4.99
1.6
3.70%
9.98
15.52
19.36
1.9
2.15
20.50%
3.80
12.27
22.04
0.832
1.84
90.90%
1.66
3.50
5.08
Where GMD indicates geometric medium diameter.
SMD is surface medium diameter. SMD=GMD*exp(3*ln2(GSD))
MMD is mass medium diameter. MMD=GMD*exp(2*ln2(GSD))
3) Mass fraction and mass partitioning in size-resolved mineralogical species
Table 3. mass fraction and mass partitioning
(a) Reference dust
REF
(b) Bulk dust
BULK
(c) Fine and coarse dust
FAC
Size-resolved
REF
REF
nick name
Exp_saharan
Exp_chinese
magg
N/A
N/A
mcal
N/A
N/A
mqtz
N/A
N/A
Size-resolved
BULK exp1
BULK exp2
BULK exp3
BULK exp4
BULK exp5
BULK exp6
BULK exp7
nick name
No calcite
No quartz
No clay
All the three
Calcite
Clay
Quartz
magg
50
50
0
25
0
100
0
mcal
0
50
50
50
100
0
0
mqtz
50
0
50
25
0
0
100
Size-resolved
nick name
fine
magg,f
FAC_exp1A
FAC_exp1B
FAC_exp1C
FAC_exp2A
FAC_exp2B
FAC_exp2C
FAC_exp3A
FAC_exp3B
FAC_exp3C
FAC_exp4A
FAC_exp4B
FAC_exp4C
FAC_A
FAC_B
5
25
45
5
25
45
0
0
0
2.5
12.5
22.5
Coarse mode dominant
10
Equal in fine and coarse
50
FAC_C
Fine mode dominant
90
coarse
mcal,f
mqtz,f
0
0
0
5
25
45
5
25
45
5
25
45
magg,c
5
25
45
0
0
0
5
25
45
2.5
12.5
22.5
45
25
5
45
25
5
0
0
0
22.5
12.5
2.5
90
50
10
mcal,c
mqtz,c
0
0
0
45
25
5
45
25
5
45
25
5
45
25
5
0
0
0
45
25
5
22.5
12.5
2.5
Results
(a)
Reference Run (REF) : the effect of size distribution
O 3 + dust
C04
D87
O98
(b)
SO 2 + dust
C04
B02
D87
O98
B02
1.0E-04
1.0E-04
1.0E-05
k_het (/s)
k_het (/s)
Chinese
1.0E-05
1.0E-06
Sahara
calcite
1.0E-07
clay
quartz
1.0E-08
1.0E-06
1.0E-09
size distribution
(c)
size distribution
NO 2 + dust
C04
D87
O98
(d)
HNO 3 + dust
B02
C04
1.0E-04
•The values of khet varies
by factor of 5 to 10 due to
dust size distrubution.
•khet by authentic dust
sample are different by
factor of 5 for O3 loss and
two orders of magnitude for
SO2 loss.  The mineralogical
composition of authentic dust
is different and it can be
represent a mixture of
mineralogical compositions.
D87
O98
Sensitivity of k _he t to factors
controlling s ize-re solve d m ine ral
com positions
B02
1.0E-01
0.6
1.0E-05
1.0E-02
1.0E-06
1.0E-08
1.0E-03
1.0E-04
1.0E-09
1.0E-05
1.0E-10
1.0E-06
1.0E-11
size distribution
size distribution
Figure 2. The values of khet of size-resolved mineral dust in REF for
Saharan soil and China loess and BULK calcite, clay aggregate, and
quartz using four dust size distribution.
sensitivity (avedev/mean)
k_het (/s)
k_het (/s)
0.5
1.0E-07
0.4
0.3
0.2
size Chinese
0.1
size_Saharan
0.0
O3
SO2
NO2
HNO3
hete rogeneous re actions
Results
BULK Run (BULK) : the effect of mass fraction of mineralogical species
(a)
(b)
O3 + dust(BULK)
k_qtz(O3)
k_cal(O3)
The sensitivity of
khet to mass fraction
depends on the
relative contribution
of each mineral
species to k_het.
SO2 + dust (BULK)
k_qtz(SO2)
k_agg(O3)
k_cal(SO2)
k_agg(SO2)
1.2E-05
9.0E-06
8.0E-06
1.0E-05
6.0E-06
8.0E-06
k_het (/s)
k_het (/s)
7.0E-06
5.0E-06
4.0E-06
6.0E-06
3.0E-06
4.0E-06
2.0E-06
2.0E-06
1.0E-06
BULK C04_exp
qu
ar
tz
c la
y
ca
lc i
te
tz
te
/q
ua
r
no
c la
y/
ca
l ci
no
qu
ar
tz
ca
lc i
te
no
qu
ar
tz
c la
y
ca
lc i
te
tz
te
/q
ua
r
c la
y
no
c la
y/
ca
l ci
qu
ar
tz
no
ca
lc i
te
no
c la
y
0.0E+00
0.0E+00
Sensitivity of k_het to factors
controlling size-resolved m ineral
com positions
BULK C04 exp
0.5
k_cal(NO2)
HNO3 + dust
k_qtz(HNO3)
k_agg(NO2)
8.0E-06
4.0E-03
7.0E-06
3.5E-03
6.0E-06
3.0E-03
5.0E-06
2.5E-03
k_het (/s)
4.0E-06
3.0E-06
2.0E-06
1.0E-03
BULK C04 exp
qu
ar
tz
c la
y
ca
lc i
te
tz
te
/q
ua
r
c la
y
no
qu
ar
tz
no
ca
lc i
te
qu
ar
tz
0.3
BULK_C04
0.2
BULK_D87
BULK_O98
0.1
c la
y/
ca
l ci
BULK C04 exp
c la
y
ca
lc i
te
tz
te
/q
ua
r
no
c la
y/
ca
l ci
no
c la
y
5.0E-04
0.0E+00
qu
ar
tz
1.0E-06
ca
lc i
te
0.4
k_agg(HNO3)
1.5E-03
0.0E+00
no
k_cal(HNO3)
2.0E-03
no
k_het (/s)
(d)
NO2 + dust
k_qtz(NO2)
sensitivity (avedev/mean)
(c )
BULK_B02
0.0
O3
Figure 3. The values of khet of BULK size-resolved mineralogical species with different
mass fractions of mineralogical compositions for C04 size distribution.
SO2
NO2
HNO3
heterogeneous reactions
Results
FAC Run (FAC) : the effect of mass partitioning of mineralogical species
(a)
O3 + dust (FAC_C04)
k_agg(O3)
k_cal(O3)
(b)
k_qtz(O3)
k_cal(SO2)
k_qtz(SO2)
5.0E-05
2.5E-05
4.0E-05
2.0E-05
k_het (/s)
k_het (/s)
SO2 + dust (FAC_C04)
k_agg(SO2)
3.0E-05
The larger mass
fraction in fine
mode, the higher
values of khet
1.5E-05
3.0E-05
2.0E-05
1.0E-05
1.0E-05
5.0E-06
Sensitivity of k_het to factors
controlling size-resolved mineral
compositions
FAC_C04_exp
4C
4b
ul
k
4B
4A
3C
3b
ul
k
3B
3A
2C
2b
ul
k
2B
2A
1C
1b
ul
k
1B
1A
4C
4b
ul
k
4B
4A
3C
3b
ul
k
3B
3A
2C
2b
ul
k
2B
2A
1C
1b
ul
k
0.0E+00
1B
1A
0.0E+00
0.8
FAC_C04_exp
0.7
NO2 + dust (FAC_C02)
k_cal(NO2)
HNO3 + dust (FAC_C04)
k_qtz(NO2)
k_agg(HNO3)
3.0E-05
3.5E-02
2.5E-05
3.0E-02
1.5E-05
1.0E-05
0.6
k_qtz(HNO3)
2.0E-02
1.5E-02
0.5
0.4
0.3
FAC_C04
FAC_D87
0.2
1.0E-02
FAC_O98
0.1
5.0E-06
5.0E-03
0.0E+00
FAC_B02
0.0
FAC_C04_exp
4C
4b
ul
k
4B
4A
3b
ul
k
3C
3B
3A
2b
ul
k
2C
2B
1C
1b
ul
k
2A
1B
1A
4C
4b
ul
k
4B
4A
3b
ul
k
3C
3B
3A
2b
ul
k
2C
2B
2A
1C
1b
ul
k
0.0E+00
1B
1A
k_cal(HNO3)
2.5E-02
2.0E-05
k_het (/s)
k_het (/s)
k_agg(NO2)
(d)
sensitivity (avedev/mean)
(c )
O3
SO2
NO2
HNO3
heterogeneous reactions
FAC_C04_exp
Figure 4. The values of khet of FAC size-resolved mineralogical species with mass partitioning of fine
and coarse modes for BULK_C04_exp as well as BULK model for C04 size distribution.
Results
Sensitivity to controlling factors in heterogeneous loss rates
Sensitivity of k_het to factors
controlling size-resolved
mineral compositions
1.0
REF : Reaction with HNO3 is the most sensitive to dust
size distribution.
ii)
BULK : Reaction with O3 is the least sensitive to mass
fraction of mineralogical species.
iii) FAC : Unlike the mass fraction, mass partitioning is
significantly affected by the dust size distribution.
0.9
D87 has the largest ratio and O98 is the least ratio.
Because the relatively small fine mode in D87 size
distribution, however,
0.8
Average deviation/Mean)
i)
0.7
fine mode distribution occupied in relatively wide range
of size distribution in O98 size distribution, the khet is
not abruptly changed.
0.6
0.5
0.4
0.3
0.2
0.1
0.0
O3
SO2
NO2
HNO3
Dust Size Diistribution
REF Chinese
REF_Saharan
BULK_C04
BULK_D87
BULK_O98
BULK_B02
FAC_C04
FAC_D87
FAC_O98
FAC_B02
iv) For heterogeneous uptake, HNO3 is the most sensitive
to size-resolved mineralogical species. O3 is also the
same trends. Mass partitioning, size distribution, and
mass fraction are important.
v) SO2 and NO2 are similar characteristics in the ensitivity
to the size-resolved mineral species. Mass partitioning,
mass fraction, and size distribution are important.
Figure 5. The comparison of (average deviation)/(mean) of
khet when the factors controlling khet considered for four
heterogeneous loss rates.
Results
3
Comparison between khet and J-values
1
J[O3(O P)], J[O3( D)], khet(O3) in C04 size distribution
1.0E-03
J(O(1D))_C04_1%H
J(O(1D))_C04_5%H
J(O(1D))_C04_10%H
J(O(3P))_C04_1%H
J(O(3P))_C04_5%H
J(O(3P))_C04_10%H
1.0E-04
BULK_C04_exp1
BULK_C04_exp2
BULK_C04_exp3
J (/s) or k_het (/s)
BULK_C04_exp4
FAC
BULK_C04_exp5
BULK_C04_exp6
BULK_C04_exp7
1.0E-05
BULK
FAC_exp1A
FAC_exp1B
FAC_exp1C
FAC_exp2A
FAC_exp2B
FAC_exp2C
1.0E-06
FAC_exp3A
FAC_exp3B
FAC_exp3C
FAC_exp4A
FAC_exp4B
FAC_exp4C
1.0E-07
0
3
6
9
12
15
18
21
24
time (hour)
Figure 6. The heterogeneous loss rates and j-values of (a) O3, (b) NO2, and (c) HNO3 when the
dust layer is located 1 km to 2km. C04 size distribution and moderate dust loading 1500 ug/m3
were considered.
J[O3(1D)]and J[O3(3P)] are dominant process during the day.
For NO2, photolysis rates is dominant.
For HNO3 and SO2, heterogeneous loss are a predominant process.
We can asses each process more realistically in terms of size and composition of dust particles.
Conclusions
i) The sensitivity of khet to size distribution is the largest in B02 size distribution
and the smallest in C04 size distribution. In comparison with photolysis study, J-values are the
largest in O98 size distribution and the smallest in C04 size distribution
ii ) The sensitivity of khet to mass fraction of mineral species depends on the relative
contribution of mineralogical species to khet. The O3 loss is the least sensitive to mass
fractions because each mineral species play a role in O3 uptake.
iii) The HNO3 is the most sensitive to the mass partitioning not only because large difference in
uptake coefficients but also the order of uptake coefficients is 1.0 x 10-2~1.0x 10-1 extremely
large.
iv) For controlling factors of khet, the magnitude of uptake coefficients is most important.
khet of O3 and khet of HNO3 are sensitive to mass partitioning, size distribution, and then, mass
fraction in decreasing order.
khet of O3 and khet of HNO3 show similar characteristics in the sensitivity to the size-resolved
mineral species. Mass partitioning, mass fraction, and size distribution are important in
decreasing order.
v) Heterogeneous reaction of HNO3 and SO2 on dust particles are dominant process over
photolysis rates. NO2 uptake is slow process relative to photolysis.
Heterogeneous loss rates of O3 varies over one order of magnitude due to size-resolved
mineral species and its has the same order of magnitude to that of the photolysis.
Appendix REF, BULK, and FAC Run
Chinese
(a)
O3 + dust -->
C04
D87
(b)
O98
SO 2 + dust -->
B02
C04
1.00E-03
D87
Sahara
O98
B02
1.00E-03
BULK_exp1
BULK_exp2
BULK_exp3
1.00E-04
BULK_exp4
BULK_exp5
k_het (/s)
k_het (/s)
1.00E-04
1.00E-05
BULK_exp6
BULK_exp7
1.00E-06
1.00E-05
FAC_1A
FAC_1B
1.00E-07
FAC_1C
FAC_2A
1.00E-06
1.00E-08
FAC_2B
size distribution
size distribution
FAC_2C
FAC_3A
(c)
NO2 + dust -->
C04
D87
(d)
O98
FAC_3B
HNO3 + dust -->
C04
B02
1.00E+00
1.00E-04
1.00E-01
D87
O98
B02
k_het (/s)
k_het (/s)
1.00E-03
1.00E-02
1.00E-05
1.00E-06
1.00E-03
size distribution
size distribution
Figure 5. The values of khet of REF, BULK, and FAC size resolved mineralogical species