The effects of size-resolved mineralogical composition

on heterogeneous chemistry on dust particle surfaces

Advisor: Prof. Irina N. SokolikGill-Ran Jeong

The 4th Earth and Atmospheric Sciences Graduate Symposium, November 10th, 2006

The roles of dust aerosols in atmospheric chemistry

Direct impact Indirect impact

Radiative radiative forcing at TOA radiative forcing at the sfcheating/coolingactinic flux

Chemicalheterogeneous chemistryon dust surface

photolysis

Dust properties

O3, SO2, NO2, HNO3 Radiative effect

Chemical effect

The role of heterogeneous reaction on dust aerosols in the chemistry-climate system

O3

SO2

NO2

HNO3

•Size•Composition•Shape•Mixing with other aerosols such as BC, OC, sulfate, nitrate, and sea-salt

Direct impact Indirect impact

Radiative radiative forcing at TOA radiative forcing at the sfcheating/coolingactinic flux

cloud properties

Chemicalheterogeneous chemistryon dust surface

photolysis

Hygroscopic CCN

Dust properties

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].

Limitations of past studies and motivation of this study

The importance of size and compositions of mineral dust in modeling andmeasurement 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

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.

1. To construct size-resolved mineralogical composition of dust particlesby 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 integratinga gas-to-particle diffusion rate constant using the Fuchs-Sutugin approximationin the transition regime. The recent data on uptake coefficients of individual mineralsand authentic dust and several dust size distributions reported from field andlaboratory experiments were used.

Approach Mass transfer on dust particles and chemical properties of dust particles

]3

1 2)(log2

2)log(logexp[

2loglog)(log

ii

iRr

i

iN

rd

dNrn

O3, SO2, NO2, HNO3

1. Alkalinity Uptake acidic gases

2. Adsorption: SO2 (g)+ O2- SO3

2- SO2 (g)+ OH- HSO3

-

3. Oxidation: SO3

2-(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

2

1

j

r

r

j )n(r)drγF(r,k

),(1

4),(

jnn

j

KfK

VrDrF

L

1pjp,j kk

2r

1rpp.jjp, (r)dr)nγF(r,k

The overall heterogeneous loss rates of a gaseous species j, kj

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

γp,j, : uptake coefficient of gaseous species j by mineral compound pnp(r) is the size distribution of mineral compound pF(r, γp,j) is mass transfer coefficient whereby the Fuchs-Sutugin approximation is applied to the gas-to-particle diffusion in the transition regime.

23 5.1 OO dust

sulfateSO dust 2

nitrateHNO dust3

nitratenitriteNO dust 5.05.02

Calcite (carbonate-containingminerals)

Iron-oxide clay aggregates

Quartz: a non-absorbing andinactive mineral of gaseous uptake.

Approach

Type of size-resolved mineral composition of dust aerosols

REF (reference dust)

BULK (bulk dust)

FAC (fine and coarse dust)

Approach

1 2 3 4

REF (khet_ref) X X

BULK (khet_bulk)

X X X

FAC (khet_fac ) X X X X

1) Composition(uptake coefficient)

2) Size distribution

3) Mass fraction ofmineralogical species

4) Mass partitioning ofmineralogical species

in fine and coarse modes

1) Uptake coefficients by main mineralogical compositions

sulfateSOb dust 2)(

23 5.1)( OOa dust

Three mainmineral groups

Mineral species orAlternativechemical elements

Clay aggregates KaoliniteIlliteMontrolliniteα-Al2O3

α-Fe2O3

Calcite CalciteDolomiteCaCO3

CaOMgO

Quartz SiO2

Authentic dust

Table 1. Uptake coefficients

Mineral species or alternative chemical elements

γ References

Kaolinite

3.0 ± 1.0 × 10-5 Hanisch and Crowley, 2003 (Atmos. Chem. Phys.)

Calcite

1.0E-5 ~ 2.0E-4 (5.0 x 10-5) best guess

Dentener et al., 1996 refer to Garland, 1974 usnig deposition velocity, γ = 4υdep/c

SiO2 5.0 ± 3.0 × 10-5 Mitchel et al., 2002 (GRL) Saharan sand

6.0 ± 3.0 × 10-5 Mitchel et al., 2002 (GRL) Michel et al., 2003 (Atmos. Environ)

Chinese loess

2.7 ± 0.9 × 10-5 Mitchel et al., 2002 (GRL) Michel et al., 2003 (Atmos. Environ)

α-Al2O3 1.6 ± 0.5 x 10-4 Usher et al., 2002 (JGR) α-Al2O3 9.5 ± 0.3 x 10-5

~ 1.0 x 10-4 Goodman et al., 2001 (J. Phys. Chem.) CaCO3 1.4 ± 0.7 x 10-4 Usher et al., 2002 (JGR) SiO2 < 1 x 10-7 Usher et al., 2002 (JGR) Saharan dust (3.9~4.6) x 10-3

(4.1~5.0) x 10-7 Ullerstam et al., 2002 (Phys. Che. Chem. Phys.)

Chinese loess 3.0 ± 1 x 10-5 Usher et al., 2002 (JGR)

1) Uptake coefficients by main mineralogical compositions

nitrateHNOd dust 3)(

nitratenitriteNOc dust 5.05.0)( 2 Three mainmineral groups

Mineral species orAlternativechemical elements

Clay aggregates KaoliniteIlliteMontrolliniteα-Al2O3

α-Fe2O3

Calcite CalciteDolomiteCaCO3

CaOMgO

Quartz SiO2

Authentic dust

Table 1. Uptake coefficients

Mineral species or alternative chemical elements

γ References

α-Al2O3 9.1 x 10-6 8.5 x 10-5 Underwood et al., 2001 (JGR)

CaO

2.2x10-5 5.4 x 10-5 Underwood et al., 2001 (JGR)

SiO2 Too low (4.0x10-10) - Underwood et al., 2001 (JGR)

Saharan dust RG*1.0 x 10-6

~ 2.0 x 10-5 Underwood et al., 2001 (JGR) Chinese loess 2.1 x 10-6

4.4 x 10-5 Underwood et al., 2001 (JGR)

Kaolinite

(11 ± 1.6) x10-2 Hanisch and Crowley, 2001 (Phys. Chem.Chem.Phys.)

CaCO3 (18 ± 4.5) x 10-2 Hanish and Crowley, 2001 (J. Phys. Chem.)v

SiO2 (2.9 ± 0.2) x 10-5 Underwood et al., 2001 (JPC) Saharan sand 1.36x10-1 Hanisch and Crowley, 2001 (Phys.

Chem.Chem.Phys.) Chinese loess

1.71x10-1 Hanisch and Crowley, 2001 (Phys. Chem.Chem.Phys.)

2) Dust size distribution

2.5μm of SMD

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))

Table 2. dust size distribution

Dust Size Distribution / Reference

Size mode Mode1 Mode2 Mode3 Mode4 Mode5

C04 rg m) 0.345 0.885 4.335

Clarke et al. [2004] σg 1.46 1.85 1.5

Mass fraction 1.80% 69.40% 28.80% GMD 0.69 1.77 8.67 SMD 0.92 3.77 12.05 MMD 1.06 5.51 14.20

D87 rg m) 0.08 0.70 4.99

D’Almeida [1987] σg 2.1 1.9 1.6

Mass fraction 1.00% 95.30% 3.70% GMD 0.16 1.40 9.98 SMD 0.48 3.19 15.52 MMD 0.83 4.82 19.36

O98 rg m) 0.07 0.39 1.9

Hess et al. [1998] σg 1.95 2.00 2.15

Mass fraction 3.40% 76.10% 20.50% GMD 0.14 0.78 3.80 SMD 0.34 2.04 12.27 MMD 0.53 3.30 22.04

B02 rg m) 0.088 0.832

Dubovik et al. [2002] σg 1.52 1.84

Mass fraction 9.10% 90.90% GMD 0.18 1.66 SMD 0.25 3.50 MMD 0.30 5.08

3) Mass fraction and mass partitioning in size-resolved mineralogical species

(a) Reference dustREF

(b) Bulk dust BULK

(c) Fine and coarse dust FAC

Table 3. mass fraction and mass partitioningSize-resolved nick name magg mcal mqtz REF Exp_saharan N/A N/A N/A REF Exp_chinese N/A N/A N/A Size-resolved nick name magg mcal mqtz BULK exp1 No calcite 50 0 50 BULK exp2 No quartz 50 50 0 BULK exp3 No clay 0 50 50 BULK exp4 All the three 25 50 25 BULK exp5 Calcite 0 100 0 BULK exp6 Clay 100 0 0 BULK exp7 Quartz 0 0 100 Size-resolved nick name fine coarse magg,f mcal,f mqtz,f magg,c mcal,c mqtz,c FAC_exp1A 5 0 5 45 0 45 FAC_exp1B 25 0 25 25 0 25 FAC_exp1C 45 0 45 5 0 5 FAC_exp2A 5 5 0 45 45 0 FAC_exp2B 25 25 0 25 25 0 FAC_exp2C 45 45 0 5 5 0 FAC_exp3A 0 5 5 0 45 45 FAC_exp3B 0 25 25 0 25 25 FAC_exp3C 0 45 45 0 5 5 FAC_exp4A 2.5 5 2.5 22.5 45 22.5 FAC_exp4B 12.5 25 12.5 12.5 25 12.5 FAC_exp4C 22.5 45 22.5 2.5 5 2.5 FAC_A Coarse mode dominant 10 90

FAC_B Equal in fine and coarse

50 50

FAC_C Fine mode dominant

90 10

Results

Reference Run (REF) : the effect of 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.

•The values of khet variesby factor of 5 to 10 due to dust size distrubution. •khet by authentic dustsample 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.

(a) O3 + dust

1.0E-06

1.0E-05

1.0E-04

C04 D87 O98 B02

size distribution

k_

he

t (/

s)

(b) SO2 + dust

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

C04 D87 O98 B02

size distributionk_h

et

(/s)

Chinese

Sahara

calcite

clay

quartz

(c) NO2 + dust

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

C04 D87 O98 B02

size distribution

k_

he

t (/

s)

(d) HNO3 + dust

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

1.0E-01

C04 D87 O98 B02

size distribution

k_h

et

(/s)

Sensitivity of k_het to factorscontrolling size-resolved mineral

compositions

0.0

0.1

0.2

0.3

0.4

0.5

0.6

O3 SO2 NO2 HNO3

heterogeneous reactions

sen

sit

ivit

y (

aved

ev/m

ean

)

size Chinese

size_Saharan

Results

BULK Run (BULK)

Figure 3. The values of khet of BULK size-resolved mineralogical species with different mass fractions of mineralogical compositions for C04 size distribution.

(a) O3 + dust(BULK)

0.0E+00

1.0E-06

2.0E-06

3.0E-06

4.0E-06

5.0E-06

6.0E-06

7.0E-06

8.0E-06

9.0E-06

BULK C04_exp

k_h

et (

/s)

k_qtz(O3) k_cal(O3) k_agg(O3)

(b) SO2 + dust (BULK)

0.0E+00

2.0E-06

4.0E-06

6.0E-06

8.0E-06

1.0E-05

1.2E-05

BULK C04 exp

k_h

et (

/s)

k_qtz(SO2) k_cal(SO2) k_agg(SO2)

(c ) NO2 + dust

0.0E+00

1.0E-06

2.0E-06

3.0E-06

4.0E-06

5.0E-06

6.0E-06

7.0E-06

8.0E-06

BULK C04 exp

k_h

et (

/s)

k_qtz(NO2) k_cal(NO2) k_agg(NO2)

(d) HNO3 + dust

0.0E+00

5.0E-04

1.0E-03

1.5E-03

2.0E-03

2.5E-03

3.0E-03

3.5E-03

4.0E-03

BULK C04 exp

k_h

et (

/s)

k_qtz(HNO3) k_cal(HNO3) k_agg(HNO3)

The sensitivity of khet to mass fraction depends on the relative contribution of each mineral species to k_het.

: the effect of mass fraction of mineralogical species

Sensitivity of k_het to factorscontrolling size-resolved mineral

compositions

0.0

0.1

0.2

0.3

0.4

0.5

O3 SO2 NO2 HNO3

heterogeneous reactions

sen

siti

vity

(av

edev

/mea

n)

BULK_C04

BULK_D87

BULK_O98

BULK_B02

Results FAC Run (FAC) : the effect of mass partitioning of mineralogical species

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.

(a) O3 + dust (FAC_C04)

0.0E+00

5.0E-06

1.0E-05

1.5E-05

2.0E-05

2.5E-05

3.0E-05

FAC_C04_exp

k_he

t (/s

)

k_agg(O3) k_cal(O3) k_qtz(O3)

(b) SO2 + dust (FAC_C04)

0.0E+00

1.0E-05

2.0E-05

3.0E-05

4.0E-05

5.0E-05

FAC_C04_exp

k_he

t (/s

)

k_agg(SO2) k_cal(SO2) k_qtz(SO2)

(c ) NO2 + dust (FAC_C02)

0.0E+00

5.0E-06

1.0E-05

1.5E-05

2.0E-05

2.5E-05

3.0E-05

FAC_C04_exp

k_he

t (/s

)

k_agg(NO2) k_cal(NO2) k_qtz(NO2)

(d) HNO3 + dust (FAC_C04)

0.0E+00

5.0E-03

1.0E-02

1.5E-02

2.0E-02

2.5E-02

3.0E-02

3.5E-02

FAC_C04_exp

k_he

t (/s

)k_agg(HNO3) k_cal(HNO3) k_qtz(HNO3)

Sensitivity of k_het to factorscontrolling size-resolved mineral

compositions

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

O3 SO2 NO2 HNO3

heterogeneous reactions

sen

siti

vity

(av

edev

/mea

n)

FAC_C04

FAC_D87

FAC_O98

FAC_B02

The larger mass fraction in fine mode, the higher values of khet

Results Sensitivity to controlling factors in heterogeneous loss rates

Figure 5. The comparison of (average deviation)/(mean) of khet when the factors controlling khet considered for four heterogeneous loss rates.

i) 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.

D87 has the largest ratio and O98 is the least ratio. Because the relatively small fine mode in D87 size distribution, however,

fine mode distribution occupied in relatively wide range of size distribution in O98 size distribution, the khet is not abruptly changed.

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.

Sensitivity of k_het to factorscontrolling size-resolved

mineral compositions

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

O3 SO2 NO2 HNO3

Dust Size Diistribution

Avera

ge d

evia

tio

n/M

ean

)

REF Chinese REF_Saharan

BULK_C04 BULK_D87

BULK_O98 BULK_B02

FAC_C04 FAC_D87

FAC_O98 FAC_B02

Results Comparison between khet and J-values

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(O3P)], J[O3(

1D)], khet(O3) in C04 size distribution

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 3 6 9 12 15 18 21 24

time (hour)

J (

/s)

or k

_h

et

(/s)

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

BULK_C04_exp1

BULK_C04_exp2

BULK_C04_exp3

BULK_C04_exp4

BULK_C04_exp5

BULK_C04_exp6

BULK_C04_exp7

FAC_exp1A

FAC_exp1B

FAC_exp1C

FAC_exp2A

FAC_exp2B

FAC_exp2C

FAC_exp3A

FAC_exp3B

FAC_exp3C

FAC_exp4A

FAC_exp4B

FAC_exp4C

BULK

FAC

J[HNO3] and khet(HNO3] in C04 size distribution

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

0 3 6 9 12 15 18 21 24

time (hour)

J (/

s) o

r k_

het

(/s

)

BULK

FAC

J[NO2] and khet(NO2) in C04 size distribution

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

0 3 6 9 12 15 18 21 24

time (hour)

J (/

s) o

r k_

het

(/s

) BULK

FAC

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

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.

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

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.

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.

(a) O3 + dust -->

1.00E-06

1.00E-05

1.00E-04

1.00E-03

C04 D87 O98 B02

size distribution

k_h

et (

/s)

(b) SO2 + dust -->

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

C04 D87 O98 B02

size distribution

k_h

et (

/s)

Chinese

Sahara

BULK_exp1

BULK_exp2

BULK_exp3

BULK_exp4

BULK_exp5

BULK_exp6

BULK_exp7

FAC_1A

FAC_1B

FAC_1C

FAC_2A

FAC_2B

FAC_2C

FAC_3A

FAC_3B(c) NO2 + dust -->

1.00E-06

1.00E-05

1.00E-04

1.00E-03

C04 D87 O98 B02

size distribution

k_h

et (

/s)

(d) HNO3 + dust -->

1.00E-03

1.00E-02

1.00E-01

1.00E+00

C04 D87 O98 B02

size distribution

k_h

et (

/s)

Appendix

REF, BULK, and FAC Run

Figure 5. The values of khet of REF, BULK, and FAC size resolved mineralogical species.