SOA Formation through Aqueous Chemistry: - MARAMA

marama.org

SOA Formation through Aqueous Chemistry: - MARAMA

9/10/2012

Organics: 30-70% of PM 2.5

SOA Formation through Aqueous Chemistry:

atmospheric evidence, chemistry, partitioning

and prediction

NASA image

Barbara Turpin, Professor

Dept. of Environmental Sciences

Rutgers University

Zhang GRL 2007

Organic PM is less well understood

Why?

Atmospheric Aerosol

Los Angeles Smog

Dept of Environmental Sciences

Visibility Degradation

Adverse Health Effects

Global Climate

scattering/absorbing

cloud condensation nuclei

Chemical and thermodynamic complexity

Measurement, predict behavior

b sp (M m -1 )

b sp (M m -1 )

Western U.S. Visibility

Visibility Degradation

Adverse Health Effects

New Particle Growth

Global Climate

scattering/absorbing

cloud condensation nuclei

Jimenez et al Science 2010; Goldstein and Galbally, EST 2007; Turpin et al., AE 2000 Zhang et al., 1994; McMurry et al., 1994

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9/10/2012

Atmospheric Aerosol

Dept of Environmental Sciences

Atmospheric Aerosol

Dept of Environmental Sciences

Myocardial infarction

Visibility Degradation

Adverse Health Effects

New Particle Growth

Global Climate

scattering/absorbing

cloud condensation nuclei

Visibility Degradation

Adverse Health Effects

New Particle Growth

Global Climate

scattering/absorbing

cloud condensation nuclei

Fresh “traffic” PM (metals and carbonaceous species)

Secondary organics – largely unstudied

The effect of PM on MI’s is believed to be linked to:

– oxidative stress, systemic inflammation, cardiovascular effects

(e.g., Brauer EHP 2008; Hoek Lancet 2002)

More rapid with the

aid of organics

(e.g., Riipinen ACP 2011; Smith PNAS 2010; Kulmala ACP 2004)

Atmospheric Aerosol

Dept of Environmental Sciences

Visibility Degradation

Adverse Health Effects

New Particle Growth

Global Climate

scattering/absorbing

cloud condensation nuclei

Important contributor to scattering (urban, rural, marine)

Light absorbing brown carbon (e.g., Gelencser 2003; Sareen 2010)

Alters aerosol hygroscopicity and CCN activity (e.g., Suda JGR

2012; Petters ACP 2007)

Earth’s atmosphere is an oxidizing environment

Photochemical reactions produce atmospheric

oxidants (e.g., ozone, OH, NO 3 , H 2 O 2 ).

Sulfate

Nitrate

SO 2

Nitric acid

NOx

NH 3

Water

Organic PM

(SOA)

Organic gases

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9/10/2012

Atmospheric chemistry – high atmos. O/C

O/C vs Vapor Pressure – Atmospheric Organic Aerosol

Atmospheric organic PM - oxidized, hygroscopic

SOA

Aerosol Mass Spectrometer (AMS) O/C ranges:

Aiken EST 2008; Jimenez Science 2009; Ng ACP 2010

Zhang et al., GRL 2007

SOA Formation: Traditional Theory (SOA gas )

Atmospheric chemistry – high atmos. O/C

Precursors >C7

1-2 oxidation steps

Produces SOA

O:C < 0.5

Intermediate H 2 O solubility

SOA gas

SOA

RH ≤ 15 %

Odum et al, ES&T 1996

Aerosol Mass Spectrometer (AMS) O/C ranges:

Aiken EST 2008; Jimenez Science 2009; Ng ACP 2010

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9/10/2012

Water is the most abundant condensed phase species

Aerosol water is 2-3 times dry particle mass, also clouds

Dry

sulfate/nitrate/ammonium

aerosols

Water associated with

sulfate/nitrate/ammonium

aerosols

mg m -2

Liao and Seinfeld, JGR 2005

Organics mostly emitted in the gas phase

CP

fom

⋅760⋅

RT

K

P

= =

o 6

CGTSP

MWom

⋅ζ

om

⋅ pL

⋅10

Carbon Balance

Central Los Angeles, Sept 9, 1993 Pankow 1994

Primary PM 2.5 ∼ 75% of primary OA evaporates

lipid soluble

O/C ∼ 0 - 0.1

AMS: HOA

Fraser et al., EST 1996

Normalized Organic Aerosol

Emission Factor

1.0

0.8

0.6

0.4

0.2

0.0

(A)

Dilution Ratio

10,000 1,000 100 10

Ambient

Conditions

Measured

Fit of data

95% CI

2

1

Organic Aerosol

Emission Factor (g kg-fuel -1 )

0

10 0 10 1 10 2 10 3

C OA

(µg m -3 ) Robinson et al, Science 2007

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9/10/2012

Gas-phase photochemistry fragments and oxidizes

O/C vs. Log P 0 for n-butane

Thus, water-soluble vapors are ubiquitous and abundant

1.0

Example: n-butane + OH radicals

0.8

Gas-phase photochemistry fragments and oxidizes

1.2

1.0

0.8

Example: isoprene + OH radicals

OH

Recycling

O OH

Glycolaldehyde

2 nd G Products

O O

GLY

1-3 days

O/C

0.6

0.4

0.2

0.0

O

2 nd G Products

OH

1 st G Products

O

28.4 days

O

+ OH

OH O

6.0 days

+ OH

Lifetime = 2.2 days

O/C

0.6

0.4

0.2

0.0

1.3 days

OH

O

OH

OOH

HO

Epoxide OrgPerox

C5 Hydroxy

carbonyl

O O

MGLY

3hrs

O

1 st G Products OH (Fragmentation)

1 st G Products

HO

O

O 10-14hrs

OH

MVK Methacrolein

(Oxidation)

OH (Fragmentation)

3hrs

Isoprene

-5 -4 -3 -2 -1 0

Log [P 0 (atm)]

-7 -6 -5 -4 -3 -2 -1 0

Log [P o atm]

Photochemistry fragments and oxidizes

Compound abundance (ppt)

Henry's

Constant

(M/atm)

glyoxal 780 3.50E+05

methylglyoxal 1,040 3.71E+03

formaldehyde 5,300 3.00E+03

acetic acid 6,570 5.50E+03

Phenol ? 3.00E+03

Methanol 3,760 2.20E+02

acetone 900 - 7000 30

MEK 200 – 3,000 20

Acetaldehyde 500 – 7,000 14

propanal 800 – 2,000 13

MVK 80 1-10 (?)

butanal 410 9.6

Methacrolein 80 5

benzene 4,000 0.18

toluene 300 – 8,000 0.15

isoprene 300 0.028

ethane 16405 0.0019

propane 3,000 – 19,000 0.0015

n-butane 1,300 – 11,000 0.0011

isopentane 10,000 - 11,363

20 most abundant

measured organic

gases (2 studies)

Los Angeles and

Pittsburgh

Lurmann et al. 1992

Grosjean et al. 1996

Millet et al. 2005

Nolte et al. 1997

Fraser et al. 1998

secondary

primary

Water-soluble vapors are ubiquitous and abundant

CMAQ model result (Carlton, in preparation)

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9/10/2012

Water-soluble vapors are ubiquitous and abundant

CMAQ model result (Carlton, in preparation)

OH

O

OH

OH

O

Isoprene

OH

SOA

Cloud

evaporation

OH

NOx

O

O3

O

NO x ,

alkenes,

aromatics

“aqueous” SOA (SOA aq )

Potential

Precursors Products

Aldehydes Diacids

Ketones

HMWC

Monoacids Oligomers

Alcohols N and S containing

Epoxides

Organic peroxides

N and S containing

Blando and Turpin, AtmosEnv, 2000

Gelencser and Varga, ACP, 2005

SOA through Aqueous Chemistry:

Partitioning driven by water solubility

oligomerization

Cloud

droplet

OH

Partitioning

SOA

Cloud Droplet Evaporation

low volatility

products

~µM

Glyoxal (C2)

glyoxal evaporation

Volatile but

glyoxal uptake

Highly water soluble

O/C = 1 OH Partitioning

~0.1-

10M

Implications

•different precursors

(Volkamer, ACP, 2009)

•higher O/C

•organic PM loading

•vertical distribution

OH

Wet aerosol

oligomerizationSOA

Aerosol water

(LWC)

Organic/

inorganic

constituents

Goal: Validate/Refine Aqueous Chemistry Model

rate constants known in many cases

(Herrmann, Monod, Stefan, Ervens)

isoprene

Modeling: Warneck AE 2003; Ervens et al. JGR 2004; Lim et al. EST 2005

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9/10/2012

Aqueous-Phase Reactions with Product Analysis

Goal: Validate/Refine Aqueous Chemistry Model

Goal: Validate/Refine Aqueous Chemistry Model

rate constants known in many cases

(Herrmann, Monod, Stefan, Ervens)

Experiments

10 - 5000 µM ORG

H 2 O 2 +hν ·OH (10 -12 - 10 -13 M)

2-5 pH

± H 2 SO 4 , HNO 3 , (NH 4 ) 2 SO 4

ORG: glyoxal, methylglyoxal,

glycolaldehyde, pyruvic acid, acetic

acid

Controls

ORG+Prod+UV

ORG+Prod+H 2 O 2

UV+H 2 O 2

± H 2 SO 4 ,…

± H 2 SO 4 ,…

Catalase to stop reactions

ESI-MS; IC-ESI-MS; FT-ICR MS; ESI-MS-MS,

UV or IC for organic acids, DOC for mass balance, H2O2

Dilute aqueous chemistry model (Lim et al 2005) reproduces oxalic,

pyruvic acid and total organic carbon at 30 µM in presence and

absence of sulfuric acid, nitric acid, ammonium sulfate

Oxalate (µM)

Total Carbon (µM)

Concentration (µM-C)

Oxalic Acid Concentration (µM)

35

30

25

20

15

10

5

0

250

200

100

150

80

100

60

50

40

0

20

1000

0

800

600

600

400

450

(a)

Glyoxal + OH

30 µM glyoxal

0 50 100 150 200

(b)

300 µM glyoxal

0 30 µM 50 glyoxal 100 150 200

(c)

Time (min)

Model Prediction

No H 2 SO 4

280 µM H 2 SO 4

840 µM H 2 SO 4

TOC measured by TOCAN

Expected TOC

Expected TOC + larger acids

0 10 20 30 40 50 60

Time (min)

Oxalic acid (µM)

10

8

6

4

2

0

100

80

60

40

20

0

400

300

200

Methylglyoxal + OH

30 µM methylglyoxal +

0.15 mM H 2O 2

Cloud relevant

~30 µM

300 µM methylglyoxal

+ 1.5 mM H 2O 2

Tan et al., EST 2009; AE 2010

without H 2

SO 4

Time (min)

0

5

10

15

20

25

30

35

40

0 10 20

H

F

But not at higher concentrations

Conductivity (µS)

unknown 2

E

unknown 3

I

A+B+C

Abundance

3 mM methylglyoxal + OH

87

4x10 4 A+B+C

2x10 4 75 131

161

175

0

6x10 5 unknown 2 177

3x10 5

0

6x10 5 177 E

3x10 5 117

0

1x10 5 103 133

F

5x10 4

177

0

2x10 4 119

177 H

1x10 4

0

2x10 5 89

I

1x10 5

0

unknown 3 235

249

3x10 4

221 263

0

0 100 200 300

Formation of

products with higher

C# than precursors

6x10 4 m/z - Higher-MW ions

Tan AE, 2010

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9/10/2012

O O 2 H 2O HO OH

H +

HO OH

glyoxal glyoxal

(hydrated)

OH

H 2O

HO

HO

R* 1

OH

OH

O 2

HO

HO

OH

OO

OH

HO

HO

OH

O

OH

+ O 2

decomposition

decomposition RO 2 HO

OH

+ O

HO OH

Glyoxal (3mM) + OH

Methylglyoxal (2mM) + OH

R* 2 4

(hydrated)

HO O

O 2 HO 2

+ HO 2

HO OH

O

2formic acid

glyoxylic 1 acid

HO

(hydrated)

(hydrated)

OH HO O O HO O

HO O

8000000

1400000

2

OO

O + O 2

149.00907

177.04022

7000000

HO OH

HO OH

HO OH

1200000

H 2O

R* 3

decomposition

6000000

1000000

decomposition RO 2

HO

O

5000000

O +

800000

HO

OH

4000000

O O

4

+ HO

R* 600000

2

(hydrated) 4

3000000

HO OH

3 oxalic acid

O 2 HO 400000

2

2000000

Glyoxal + OH

Methylglyoxal + OH

oxalic acid

CO 2

CO 1000000

200000

4

OH O O decomposition O

2

+ CO 2

0

0

HO O

HO 4

100 125 150 175 200 225 250 275 300 100 125 150 175 200 225 250 275 300

H 2O

R* 4 Gly – YB Lim et al ACP 2010

m/z-

-

m/z-

-

O 2 HO 2

radical-radical rates from

CO FTICR-MS (Negative (negative Mode: mode) Acid products only)

4 2 Guzman et al JPC 2006

Glyoxal

Aqueous Mechanism

Ion abundance

Signal

Key Radical – Radical Products

Signal

Glyoxal, Methylglyoxal

Can explain formation of higher carbon number products

and reproduce some prominent higher C# products

Tartaric acid production from glyoxal + OH

Measured Tartaric + Malonic Acids

Modeled Tartaric Acid

Model produces oxalate,

pyruvate in clouds –

oligomers in wet aerosols

(OH radical = 10 -12 M)

Clouds: O/C 1 – 2

Aerosols: O/C ~ 1

PA - Guzman et al JPC 2006

Gly – YB Lim et al ACP 2010

MG – YB Lim et al, in prep

Gly – YB Lim et al ACP 2010

MG – YB Lim et al, in prep

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9/10/2012

Glyoxal + OH: Aqueous Oxidation Products

2.5

Methylglyoxal + OH: Aqueous Products

2.5

Oxalic acid

O/C

2.0

1.5

1.0

0.5

0.0

O

OH

OH

O

OH OH

Tartaric acid

O

Ammonium

Oxalate

Oligomers

OH

OH

O

OH

O O

OH

O O

6.7 days

HO OH

Oxalic acid

OH

OH

Cloud

Wet aerosol

OH and Non-radical

Wet aerosol; cloud droplet aqueous-phase

evaporation

OH

gas-phase

O O

GLY

6 min

n-heptane

1.7 days

O/C

2.0

1.5

1.0

0.5

0.0

HO

Oligomers

O

Ammonium

Salt

HO

O

HO

OH O

Pyruvic acid Acetic acid

Photolysis O O

OH

~2 hrs

Wet aerosol

OH

HO O OH

OH Wet aerosol OH Cloud

O O OH and Non-radical

O O 10 min

OH Wet aerosol; cloud droplet aqueous-phase

evaporation

OH

MGLY

OH

O O

OH

OH

n-heptane

gas-phase

O

O

OH

OH

O O

Mesoxalic acid

2 - 7 hrs

OH

1.7 days

-13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1

-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1

Log [P o atm]

Log [P o atm]

Aqueous chemistry helps explain ambient O/C

Condensed (aqueous) chemistry leads to higher O/C ratios

Oligomers (aerosols), organic salts (clouds) – low volatility

SOA aq

SOA

SOA gas

Aerosol Mass Spectrometer (AMS) O/C ranges:

Aiken EST 2008; Jimenez Science 2009; Ng ACP 2010

SOA: rxn with OH radicals in clouds/aerosols

Compound

Henry's

Constant

(M/atm)

Aqueous-phase

OH reaction

rate (M/s)

SOAaq

HMWC/

Oligomer

formation

glyoxal 3.50E+05 1 E09 yes yes

methylglyoxal 3.71E+03 6 E08 yes yes

acetic acid 5.50E+03 2 E07 yes no

acetone 30 2 E08 yes yes

methacrolein 5 2 E09 yes yes

MVK 1-10 (?) 8 E08 yes yes

phenol 3.00E+03 7 E09 no no

formaldehyde 3.00E+03 no no

acetaldehyde 14 3 E09 no no

methanol 2.20E+02 9 E08

MEK 20 1 E08

propanal 13 4 E09

butanal 9.6 4 E09

ALSO STUDIED

glycolaldehyde 2 E09 yes yes

pyruvic acid 6 E07 yes yes

Guaiacol and Syringol yes yes

OTHERS TO STUDY

epoxides

organic peroxides

20 MOST ABUNDANT WS MEASURED

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9/10/2012

Also….

Other oxidants:

ozone, nitrate radical?

Droplet Evaporation:

glyoxal

Formation of acetal and aldol condensation oligomers

Wet aerosols: Non-radical chemistry:

acid and ammonium catalyzed oligomerization

orgN formation (ammonium, amines)

light absorbing (brown) carbon (incl. from formaldehyde, MG)

OrgS formation in wet aerosols:

radical rxns, esterification, adducts

Including with IEPOX + acidic sulfate

Questions and Challenges:

•How important is aqSOA? In cloud and/or aerosol water?

Modeling chemistry or yields

• Smog chamber or flow tube experiments

•How do the products partition; volatility of aqSOA?

•What are the major precursors in the real atmosphere?

Abbatt, Anastasio, Claeys, Cocker, Cordova, De Haan, Flagan, Galloway, Grgic, Guzman,

Herrmann, Hoffmann, Jimenez, Kamens, Keutsch, Lee, Liu, Maenhaut, Michaud, McNeill,

Monod, Noziere, Perri, Sareen, Seinfeld, Shapiro, Sun, Surratt, Tolbert, Volkamer, Wortham,

Yasmeen, Q. Zhang, and….

Questions and Challenges:

•How important is aqSOA? In cloud and/or aerosol water?

Modeling chemistry or yields

• Smog chamber or flow tube experiments

•How do the products partition; volatility of aqSOA?

•What are the major precursors in the real atmosphere?

Edney and Cocker papers – no

effect of RH on aromatic SOA

yields

Zhou: toluene SOA yield

depends on liquid water

Liquid water, not RH,

is the important variable

Zhou et al AE, 2011

Gas + condensed phase smog

chamber experiments – several

challenges

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9/10/2012

Volkamer – suggests faster with OH

Questions and Challenges:

SOA formation

faster with OH

radical (light)

SOA yields

increased with

seed LWC not

OM

Volume (µm 3 cm -3 )

WSOC photochemistry of CHOCHO

•How important is aqSOA? In cloud and/or aerosol water?

Modeling chemistry or yields

• Smog chamber or flow tube experiments

•How do the products partition; volatility of aqSOA?

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9/10/2012

Effective vapor pressure: ~ 10 -6 – 10 -7

2.5

Cloud-relevant MG + OH and evaporation

Effective vapor pressure (3-6 x 10 -7 atm)

Oxalic acid

Slopes

QC Check:

Malonic Acid

Measured 6 x 10 -8 atm

Pankow & Asher: 2 x 10 -7 atm

MG + OH pH 7

MG + OH pH 3

3 x 10 -7 atm

6 x 10 -7 atm

Ortiz et al., 2012; Ortiz et al. in prep

O/C

2.0

1.5

1.0

0.5

0.0

HO

Oligomers

O

Ammonium

Salt

OH

O

OH

O

OH

OH

OH

O

OH

O O

OH

-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1

HO

O

HO

Log [P o atm]

O

O

OH

OH

O O

Mesoxalic acid

Pyruvic acid Acetic acid

Photolysis O O

~2 hrs

Wet aerosol HO O OH

OH Wet aerosol OH Cloud

Non-radical

O O 10 min

aqueous-phase

MGLY

OH

gas-phase

2 - 7 hrs

OH

n-heptane

1.7 days

Questions and Challenges:

•How important is aqSOA? In cloud and/or aerosol water?

Modeling chemistry or yields

Other precursors?

Experiments with cloudwater surrogates

• Smog chamber or flow tube experiments

•How do the products partition; volatility of aqSOA?

•What are the major precursors in the real atmosphere?

Filtered rainwater

+ OH radicals

Camden ~ heavily industrialized city

Pinelands ~ 30 miles east of Camden

Rainwater heavily influenced by

aged pollutants from W and SW

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9/10/2012

Experiments with cloudwater surrogates:

PEGASOS: Po Valley, Italy

July 2012

Ambient watersoluble

gases

Methylglyoxal + OH radical cloud chemistry

Tan et al., AE 2010

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9/10/2012

Precursors are mostly in ESI-MS positive mode (aldehydes,

alcohols, organic peroxides). Products in negative mode

(organic acids)

X 10 3

Relative ion abundance

IC Realtime

Preliminary PEGASOS

Retention Time = 22.9 min (Oxalic(Po Acid)

Valley) Results

Conductivity

Conductivity (µS)

Abundance

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0 PV-MC-120609JK Cuvette Exp Real-Time

Pre 0 0 10 ESI-MS 20 30 negative 40 60 mode 80 100 120 150

Time (min)

Reaction Time

Time vs 22.9 min (OA)

700

600

500

400

300

200

100

ESI-MS

m/z- 89

AqueousSOA helps to explain: (Lim et al., ACP 2010)

•High atmospheric O/C

Aiken 2008; Jimenez 2009; Ng 2010

•Atmospheric abundance of oxalate

Kawamura 1993; Rogge 1993; Myriokefalitakis 2011

•HMWC – largest component of OM

Ambient O/C

LV-OOA

SV-OOA

0.5 – 1.1

0.2 – 0.6

Zappoli 1999; Fuzzi 2001; Kiss 2002; Kalberer 2004

0

Pre 0 0 10 20 30 40 60 80 100 120 150

Time (min)

Reaction Time

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9/10/2012

SOA above clouds

↑oxalate/sulfate, OC/EC, WSOC/OC,…

GoMACCS

Increased SOA with LWC

MASE I/II, ICARTT, GoMACCS

Atlanta

Sorooshian et al, GRL 2010

Sorooshian et al, GRL 2010

Hennigan et al., GRL 2008; ACP 2009

Highest OA when organics in droplet mode

Regime II

marine clouds,

sunny afternoons

highest OM

droplet mode

Regime III

hot and dry

condensation mode

Conclusions (SOAaq through OH oxidation):

SOA forms through reactions in atmospheric waters

SOA aq precursors: aldehydes, ketones, alcohols, organic

peroxides, and/or epoxides

• Products in clouds: organic acid/salts

• Products in wet aerosols: HMWC, oligomers, orgS, orgN

Droplet mode

Condensation mode

Hersey et al, ACP 2011

• Where? photochemical activity, high liquid water conc.

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9/10/2012

Acknowledgements:

EPA STAR 2008

Students and Postdocs -

Yong Bin Lim, Natasha Hodas, Jeff Kirkland, Diana Ortiz,

Anjuli Ramos, Katye Altieri, Mark Perri, Yi Tan, Mary Moore

Collaborators -

Cristina Facchini, Stefano Decesari, Frank Keutsch, Jeff Collett,

Amy Sullivan, Sybil Seitzinger, Annmarie Carlton, Barbara

Ervens

Funding -

NSF, NOAA, EPA STAR

Effect of water on semivolatile partitioning

Does SOA have access to OM at high LWC?

Into a single aerosol phase:

1. reduces MW om increasing K p

2. hydrophilic – reduces ζ i , increasing K p

Microscopic Mixing:

3. hydrophobic – increases ζ i , decreasing K p 1.Between particle heterogeneity

Seinfeld and Pankow, 2003

External to internal mixture with aging

2. Within particle heterogeneity

Close to sources

Downwind

(well aged)

Pankow, 1994

Liquid organic – water+electrolyte phase separation to high RH

for organics with O:C


9/10/2012

17

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