Envr 890: Lecture 1Envr 890: Lecture 1

Department of Environmental Science and Engineering

UNC, Chapel Hill

http://www.unc.edu/courses/2008fall/envr/890/001/

Class Objective:Class Objective: Begin Development of a Begin Development of a Secondary Organic Aerosol mechanism Secondary Organic Aerosol mechanism for Isoprene and learn how to run the for Isoprene and learn how to run the

ESE Aerosol Smog Chamber in PittsboroESE Aerosol Smog Chamber in Pittsboro

C=C-C=CC=C-C=CH

HCH3

H

HH

Class Objective:Class Objective: Begin Development of a Begin Development of a Secondary Organic Aerosol mechanism Secondary Organic Aerosol mechanism for Isoprene and learn how to run the for Isoprene and learn how to run the

ESE Aerosol Smog Chamber in PittsboroESE Aerosol Smog Chamber in Pittsboro What are organic aerosols? What fraction of the aerosol environment

are they? What do we need to build a chemical

mechanism? What do we need to measure? Start collecting papers on Isoprene and

SOA formation

Aerosol Associated Organics:Aerosol Associated Organics: An Historical PerspectiveAn Historical Perspective

Secondary organic aerosols how much Secondary organic aerosols how much is out thereis out there

Modeling approaches for SOAModeling approaches for SOA AnalysisAnalysis SamplingSampling Where do we go from hereWhere do we go from here

What should you get from these What should you get from these lectures?lectures?

What are SOA Why are they important? How much is there?

Are they a constant fraction of TSP or the organic fraction?

How are they measured? How are they formed? Which

compounds are involved? How do we model them?

What should you get from these What should you get from these lectures?lectures?

How do we model them?How do we model them? What is equilibrium partitioningWhat is equilibrium partitioning What is a numerical solution What is a numerical solution

approachapproach How does this differ from a chemical How does this differ from a chemical

mechanism approach?mechanism approach? What are vapor pressure and activity What are vapor pressure and activity

coefficients?coefficients? Which compounds contribute to SOA?Which compounds contribute to SOA? What are two major unknowns in What are two major unknowns in

current models?current models?

Reasons to study secondary organic aerosol formation (SOA)

Global model calculations are sensitive to fine particles in the atmosphere

Biogenic SOA particles serve as sites for the condensation of other reacted urban organics

The result is haze and visibility reductions

Do SOA push us beyond the AAQS PM2.5 standard? Are SOA more/less toxic than primary particle emissions?

red= +2oC, yellow =+3 oC, blue = +10C

red= +2oC, yellow =+3 oC, blue = +10C

Thailand

Beijing, in July 1987

Beijing, April 2006

A sunny day in Beijing, April 2006

Air Pollution in Northern Thailand

ChiangMai is similar to Los Angeles in the US; it is surrounded by mountains

MasteryMastery of Fire of Fire

400,000 years ago in Europe 400,000 years ago in Europe

100,000 years ago in Africa100,000 years ago in Africa

M. N. Cohne, 1977M. N. Cohne, 1977

From a global perspective, fire From a global perspective, fire results in huge emissions of black results in huge emissions of black carbon into the atmospherecarbon into the atmosphere

Biomass burningBiomass burning 6x106x1012 12 gg Fossil fuel burningFossil fuel burning 7x107x1012 12 gg

Biogenic aerosolsBiogenic aerosols 13-60x1013-60x101212gg

What is the Composition of Particulate Matter???

Composition of LA Particulate Matter (adjusted for smoggy days)((Rogge &Cass et al, 1993, Turpin et al, 1991)

NH4 10nitrate 20sulfate 11EC 6other 23OC 30

Percent mass

What are Organic AerosolsWhat are Organic Aerosols??

organic liquid layer

inner solid core inorganic/carbon

H2O

H2SO4

Semi-volatile organics

What fraction of ambientParticulate matter is organic???

Fresh wood soot (0.5 m scale)

Benzo[a]fluorene

Benzo[ghi]perylene

Naphthalene

Associated with combustion emissionsAre PAHs

Professor Grimmer fractionated Professor Grimmer fractionated different exhaust extractsdifferent exhaust extracts

PAH 2&3 rings

PAHs>3 rings

Total

Total-PAHs

uv orfluorescencedetector

HPLCTotal

hexane MeCl2 ACN

painted on the skin of micepainted on the skin of mice implanted in the lungs of ratsimplanted in the lungs of rats

0

10

20

30

40 %

can

cers

TotalTotal-PAHs

PAHs 2&3 ringsPAHs > 3 rings

rat lungs Mouse-skin

0

10

20

30

40 %

can

cers

TotalTotal-PAHs

PAHs 2&3 ringsPAHs > 3 rings

rat lungs Mouse-skin

Total minus the Total minus the PAH fractionPAH fraction

0

10

20

30

40 %

can

cers

TotalTotal-PAHs

PAHs 2&3 ringsPAHs > 3 rings

rat lungs Mouse-skin

0

10

20

30

40 %

can

cers

TotalTotal-PAHs

PAHs 2&3 ringsPAHs > 3 rings

rat lungs Mouse-skin

In the 1980s many studies were showing In the 1980s many studies were showing that combustion particle extracts that combustion particle extracts expressed Ames bacterial mutagenicityexpressed Ames bacterial mutagenicity

Atmospheric reactions and aging Atmospheric reactions and aging could could alter the mutagenic responses of alter the mutagenic responses of combustion particlescombustion particles

aged wood smoke +O3+NO2

aged wood smoke +NO2

fresh wood smoke

0

100

200

300

400

500

600

700

reve

rta

nts

/pla

te

0 100 200 300 400 500 600 ug extract/plate

Kamens et al, ES&T, 1984,1985

Nitro-PAH were implicated in Nitro-PAH were implicated in giving rise to mutagenic giving rise to mutagenic increases increases

NO2

Gas Phase PAH reactionsGas Phase PAH reactions NPAH NPAH((Arey and Atkinson et al.)Arey and Atkinson et al.)

Fluoranthene

2-nitrofluoranthene

NO2

+ H2O

+ OH HOH

+ NO2

HOH

NO2 H

Kinetic models Kinetic models at UNCat UNC predicted nitro-PAH predicted nitro-PAH in the particle phase from gas phase PAH in the particle phase from gas phase PAH reactions in sunlight reactions in sunlight (Fan et al., Atmos. (Fan et al., Atmos. Envir.1995, 1996)Envir.1995, 1996)

NONO22

Do other atmospheric reactions Do other atmospheric reactions bring about the production of new bring about the production of new aerosol matter???? aerosol matter????

Secondary organic Secondary organic aerosolsaerosols (SOA)(SOA) are organic are organic compounds thatcompounds that reside in the reside in the aerosol phaseaerosol phase as a result of as a result of atmospheric reactions that occur in atmospheric reactions that occur in

either theeither the gasgas or or particle particle phasesphases..

Do we see any Do we see any chemical chemical evidence for SOA formation?evidence for SOA formation?

F.W.Went published papers on biogenic emissions from vegetation over 40 years ago.

He posed the question, “what happens to the 17.5x107 tons of terpene-like hydrocarbons or slightly oxygenated hydrocarbons once they are in the atmosphere each year?”

Went suggests that terpenes are removed from the atmosphere by reaction with ozone

attempts to demonstrate “blue haze” formation

Went suggests that terpenes are removed from the atmosphere by reaction with ozone

attempts to demonstrate “blue haze” formation by adding crushed pine or fir needles to a jar with dilute ozone.

Over a eucalyptus forest in Over a eucalyptus forest in Portugal Portugal Kavouras et al.Kavouras et al. (1998,1999)(1998,1999) show evidence for show evidence for terpene reaction products in terpene reaction products in aerosolsaerosols

Terpenes products

Kavouras et al, 1998 ng m-3

pinic acid 0.4 - 85pinonic acid 9 - 141norpinonic acid 0.1 - 38Pinonaldehyde 0.2 - 32

Nopinone 0.0 - 13

-pinene -pinene

Turpin and co-workersTurpin and co-workers

In the LA area (estimated on smoggy In the LA area (estimated on smoggy

days from days from OC OC //ECEC ratios ratios), as much as ), as much as 50 - 50 - 80%80% of the of the aerosolaerosol organic carbonorganic carbon comes from comes from secondary aerosol secondary aerosol formationformation (1984 and 1987 samples) (1984 and 1987 samples)

In Atlanta in 1999, SOA averaged 46% of the In Atlanta in 1999, SOA averaged 46% of the total OC but with highs of 88% total OC but with highs of 88%

Turpin Approach for SOA formationTurpin Approach for SOA formation The primary aerosol elemental carbon The primary aerosol elemental carbon (EC)(EC)pripri and and

particle organic content particle organic content (OC)(OC)pripri in an un-reacted in an un-reacted

airshed are measured and a primary ratio of airshed are measured and a primary ratio of {{OC OC //ECEC}}pripri is determined is determined (Turpin et al for 1984 and 1987 aerosol (Turpin et al for 1984 and 1987 aerosol samples)samples)

Under SOA formation OCUnder SOA formation OCtottot and EC and ECtottot are measured are measured

OCOCsecsec= = OCOCtottot- - OCOCpri pri

OCOCpripri = EC = EC {{OCOC /EC} /EC} pripri

On smoggy days in California ~50 - 80% of the organic On smoggy days in California ~50 - 80% of the organic carbon comes from secondary aerosol formationcarbon comes from secondary aerosol formation

Spyros Pandis also recently looked Spyros Pandis also recently looked at OC/EC ratios (Pittsburgh area)at OC/EC ratios (Pittsburgh area)

He estimates that SOA formation can He estimates that SOA formation can account for 35-50% of the organic account for 35-50% of the organic carboncarbon

OC/EC Ratio and Photochemical Activity

0

2

4

6

8

10

12

14

15-Jul 16-Jul 17-Jul 18-Jul 19-Jul

OC

/EC

Ra

tio

0

10

20

30

40

50

60

70

80

90

100

O3

(p

pb

)

OC/ECO3

Pittsburgh, 2001

Characteristics of carbonaceous aerosols in Beijing, ChinaYele Suna, Guoshun Zhuang, Ying Wang, Lihui Han, Jinghua Guo, Mo Dan, Wenjie Zhang, Zifa Wang, Zhengping Hao, Atmos, Environ. 38 (2004) 5991–6004

coal burning, traffic exhaust, and dustcoal burning, traffic exhaust, and dust from the long-range transportfrom the long-range transport

Mineral aerosol from outsideMineral aerosol from outside Beijing Beijing accounted for 79% of the total PM10 accounted for 79% of the total PM10 minerals and 37% of the PM2.5 in minerals and 37% of the PM2.5 in winter. winter.

Characteristics of carbonaceous aerosols in Beijing, ChinaFengkui Duan, Kebin He, Yongliang Ma, Yingtao Jia,Fumo Yang, Yu Lei, S. Tanaka, T. Okuta, Chemosphere 60 (2005) 355–364

OC/EC ratio (on a 1.5 basis showed that OC/EC ratio (on a 1.5 basis showed that SOC accounted more than SOC accounted more than 50%50% for the total for the total organic carbon. In winter, the SOC organic carbon. In winter, the SOC contribution to OC was also significant, and contribution to OC was also significant, and as high as as high as 40%.40%.

If we look at the IR spectra of aerosols collected from the smoky mountains, they look like lab aerosols from acid catalyzed

particle phase reactions of carbonyls…

0

0.001

0.002

0.003

0.004

0.005

5001000150020002500300035004000

wavelength (cm-1)

ab

so

rba

nc

e (

gly

ox

al)

glyoxal/acid-catalyst

Heterogeneous reactions as seen in Heterogeneous reactions as seen in the IR region (Myoseon Jang)the IR region (Myoseon Jang)

0

0.001

0.002

0.003

0.004

0.005

5001000150020002500300035004000

wavelength (cm-1)

ab

so

rba

nc

e (

gly

ox

al)

-0.1

-0.05

0

0.05

0.1

0.15

ab

so

rba

nc

e (

Sm

ok

y M

ou

nta

ins

)

glyoxal/acid-catalyst

Smoky Mountains SOA

C-O-C bonds

How does the scientific community How does the scientific community treat toxic organics that are in the treat toxic organics that are in the

gas and particle phases ?gas and particle phases ?

In the 1980s In the 1980s Yamasaki, Bidelman, Yamasaki, Bidelman, PankowPankow began to investigate the began to investigate the equilibrium distribution ofequilibrium distribution of PAHs, PAHs, alkanes, and chlorinated organicsalkanes, and chlorinated organics between the gas and the particle between the gas and the particle phases.phases.

K PAH

PAH TSPp

part

gas

PAHPAHgas gas + surface + surface PAH PAHpartpart

K P A H

P A H y

g as

p art

TSP

Yamasaki (1982)Yamasaki (1982)

Collects Hi-vol filters+PUFCollects Hi-vol filters+PUF

filter

PUF

Yamasaki (1982)Yamasaki (1982)

Collects Hi-vol filters+PUFCollects Hi-vol filters+PUF Analyzes for PAHsAnalyzes for PAHs

filter

PUF

Yamasaki (1982)Yamasaki (1982)

Collects Hi-vol filters+PUFCollects Hi-vol filters+PUF Analyzes for PAHsAnalyzes for PAHs

BaABaA

log Klog Kyy

1/Tx10001/Tx1000

filter

PUF

Yamasaki (1982)Yamasaki (1982)

filter

PUF

Collects Hi-vol filters+PUFCollects Hi-vol filters+PUF Analyzes for PAHsAnalyzes for PAHs

BaABaA

log Klog Kyy

1/Tx10001/Tx1000

Yamasaki’s relationshipYamasaki’s relationship

This gives a log KThis gives a log Kyy = -a(1/T)+ b = -a(1/T)+ b which is which is

compound specificcompound specific

Ideally from the regression values of Ideally from the regression values of a and b,a and b, one can estimate the partitioning of a given one can estimate the partitioning of a given compound in any atmosphere at a given temp. compound in any atmosphere at a given temp. and TSPand TSP

Kgas

part TSPy [ ]

[ ] /

log Klog Kp p = -log P= -log Pssoo + const. + const.

Relate solid saturated vapor pressures with Kp

log Pso

log Kp

naphthalenenaphthalene

BaPBaP

PyrenePyrene

log Klog Kp p = -log P= -log PooLL + const. + const.

PAHs,PAHs, alkanesalkaneschlorinatedchlorinated organics organics

slope = -1

log Po(L)

log Kp

Problems with the theoryProblems with the theory

many aerosols are composed of 40-100% many aerosols are composed of 40-100% organicsorganics

This gives much more than a mono-layer This gives much more than a mono-layer of coverageof coverage

log Klog Kpp= m log P= m log Poo(L)(L)+ c+ c

KR T

p M wpLo

7 5 0 1

1 0 9

. fom

In 1994 James Pankow fixes the theory for liquid particles

Can we chemically / kinetically Can we chemically / kinetically model SOA Formation???model SOA Formation???

Numerical fittingNumerical fitting Semi-explicitSemi-explicit

From a modelingFrom a modeling perspective perspective Equilibrium Organic Gas-particle Equilibrium Organic Gas-particle partitioningpartitioning provides a context for provides a context for addressing SOA formationaddressing SOA formation

Gas/Particle PartitioningGas/Particle Partitioning

particleParticle typeCompound Temperature

Humidity

gas

Thermodynamic Equilibrium?

TSPC

CK

gas

partp

Cgas +surf Cpart

Kp will vary with 1/Po

Odum-Seinfeld Model SOA modelOdum-Seinfeld Model SOA model

Y= MY= Moo / / HC HC

HC = HC = ROG ROG

Y Y MK

K Mii

o

i om i

om i oi

,

,( )1

Odum theory

- pinene- NOx experiments by Odum

Y Mo(g/m3) 1 0.012 1

2 0.028 7

3 0.059 22

4 0.067 34

5 0.078 38

6 0.122 83

7 0.125 94

Y MK

K MM

K

K Mo

om

om oo

om

om o

1 1

1

2 2

21 1,

,

,

,( ) ( )

Y = M= Moo / / HC HC

-pinene

Y MK

K MM

K

K Mo

om

om oo

om

om o

1 1

1

2 2

21 1,

,

,

,( ) ( )

Y MK

K MM

K

K Mo

om

om oo

om

om o

1 1

1

2 2

21 1,

,

,

,( ) ( )

Numerical fitting values for Kom and for OH, O3, and NO3 reactions with terpenes and sesquiterpenes were developed by Griffin and Sienfeld et al.

From the averages for OH, O3, and NO3 , the amounts of atmospherically reacted terpenes and sesquiterpenes were estimated ( HC HC ) ) by Griffin and Sienfeld et al.

Y= MY= Moo / / HC HC

Globally, biogenic emissions

13-24x1012g y-1 of aerosol mass

Gives little insight into the chemical nature of products involve in SOA formation

From a global perspective, fire From a global perspective, fire results in huge emissions of black results in huge emissions of black carbon into the atmospherecarbon into the atmosphere

Biomass burningBiomass burning 6x106x1012 12 gg Fossil fuel burningFossil fuel burning 7x107x1012 12 gg

Biogenic aerosolsBiogenic aerosols 13-60x1013-60x101212gg

Semi explicit models link gas and particle phases

C=OO

cis-pinonaldhyde

particleC=OO

Gas phase reactions

K

R T

p M wpLo

7 5 0 1

1 0 9

. fom

Kp = kon/koff

[ [ iigasgas] + [part] ] + [part] [ [ iipartpart]] kon

koff

particle

kon

koff

C=OO

Kp = kon/koff

koff = kbT/h e -Ea/RT

CHOOO

CH3

OO

O

Criegee2

Criegee1OO O

-pinene

O3

COOHCOOH

pinic acid

+ otherproducts

O

pinonic acid

CHOO

COOH

+ CO, HO2, OH

COOHO

norpinonaldehyde

norpinonic acid

Mechanism

pinonaldehyde

OH

OO

O2

+

(a)(b)

(c)

(d)

(e)

pinonaldehyde

acetone

O

OO.

NO2NO

O

O.

pinald-oo

OH

pinonic acid

O

pinO2

OO.

NO2

NO

organic nitrate

+HO2

+NO2

pinald-PAN

=o

=o

=o

=o

=o

=o

=o

OO.

O2

=o

OO=C8=O

C8-oo.

O2

NO2NO

O

+ h

+

+CO+HO2=o

OO.

NO2NO

=o

=o+HO2

+ h

NO2NO

=o

OO.

C8-oo. (C8O2)

+CO+HO2

NO2

NO

(f)

(g)

CO2+

pinO2H2O+

+HO2

O2

OO

H3C-OO.

+oxygenated products

+NO2

+H3C-OONO2PAN

(stab-oxy)

+HO2

norpinonaldehyde

OOH

O=o+

pin-ooH

+OH

O

OO.

=o

NO2

NO

+CO2

norpinaldPAN

+NO2

+HO2

norpinonic acid+norpin-ooH

O

OONO2

=o

+O2

ONO2

=o

+

=o

ONO2

+

organic nitrate

Overall kinetic MechanismOverall kinetic Mechanism

linked gas and particle phase rate linked gas and particle phase rate expressionsexpressions

Particle Phase reactions

particle

C=OO

cis-pinonaldhyde

C=OO

polymers

Gas phase reactions

Particle Phase reactions

particle

C=OO

cis-pinonaldhyde

C=OO

polymers

Gas phase reactions

Particle Phase reactions

C=OO

cis-pinonaldhyde

C=OO

polymers

Gas phase reactions

A

B

C

D

[H3O+]

O

OOH

O

O

OH

O

OH

O

[H3O+]

O

OH

OH

OO

O

O

O O

HO

O

O

1

[H3O+]

4

2

OH

H2C

O

O O

[H3O+]

O

O

O

HO

O O

HO

3

O

O

OH

O

O CH2

O

O

OH

2

2

9

O O

HO

4

O

6

O

HOb

a

a

5

b

7 8

O

O

2

2

10 11

A

B

C

D

[H3O+]

O

OOH

O

O

OH

O

OH

O

[H3O+]

O

OH

OH

OO

O

O

O O

HO

O

O

1

[H3O+]

4

2

OH

H2C

O

O O

[H3O+]

O

O

O

HO

O O

HO

3

O

O

OH

O

O CH2

O

O

OH

2

2

9

O O

HO

4

O

6

O

HOb

a

a

5

b

7 8

O

O

2

2

10 11

pinonaldehyde

2 x

Pinonaldehyde dimerization

ESI-QTOF mass spectrum of SOA from ESI-QTOF mass spectrum of SOA from reaction of reaction of -pinene + O-pinene + O33 + acid seed + acid seed

aerosolaerosol (Tolocka et. al (Tolocka et. al., ., 20042004))

200 300 400 500 600 700 800 900 1000

m/z

337.

18 351.

18

361.

21

377.

2

393.

2

407.

2

423.

2

439.

2

453.

21 489.

32

300 320 340 360 380 400 420 440 460 480 500

321.

21

m/z

17

7.0

7

19

1.1

2 20

7.1

1

22

5.1

12

33

.14

24

5.1

2

25

5.1

82

61

.11

28

9.1

8

30

1.1

8

31

3.2

3

32

7.1

6

34

1.2

35

9.2

36

0.2

150 200 250 300 350

Inte

nsity,

A.U

.

m/z

O

OH

O

H2C

O

177

207

341

261289

91

77

.07

19

1.1

2 20

7.1

1

22

5.1

12

33

.14

24

5.1

2

25

5.1

82

61

.11

28

9.1

8

30

1.1

8

31

3.2

3

32

7.1

6

34

1.2

35

9.2

36

0.2

150 200 250 300 350

Inte

nsity,

A.U

.

m/z

O

OH

O

H2C

O

177

207

341

261289

9

M Na+ (ESI-QTOF Tolocka et al, 2003)

Particle phase pinonaldehyde dimers Particle phase pinonaldehyde dimers from from -pinene +O-pinene +O3 3 on on acid particlesacid particles

Similar results were obtained by Hartmut Herrmann’s Similar results were obtained by Hartmut Herrmann’s group group (Atmos Envir, 2004)(Atmos Envir, 2004)

Chemical SystemChemical System

-pinene

+ NOx+ sunlight + ozone----> aerosols

Simulations of outdoor smog Simulations of outdoor smog chamber datachamber data

0.95 ppm -pinene + 0. 44ppm NOx

O3NO

NO2

NO2

model

data

Time in hours EST

pp

mV

Gas phase pinonaldehdye

OO

mg

/m3

Time in hours EST

Particle phase

model TSP

mg

/m3

Particle phase

model TSP

mg

/m3

Measured particle mass vs. model

data

Time in hours EST

Much lower terpene concentrations Much lower terpene concentrations

Different background aerosols which Different background aerosols which have different chemical and physical have different chemical and physical propertiesproperties

Low volatility gas phase products will Low volatility gas phase products will have different interactions with have different interactions with different pre-existing particlesdifferent pre-existing particles

The Real AtmosphereThe Real Atmosphere

New UNC aerosol smog chamberNew UNC aerosol smog chamber

Dual 270mDual 270m33 chamber chamber fine particle t fine particle t 1/21/2 >17 h >17 h

0.1 ppmV Toluene 0.1 ppmV Toluene + 0.1 ppm NOx+ 0.1 ppm NOx

072705S

0.0

0.1

0.2

0.3

0.4

0.5

8:00 10:00 12:00 14:00 16:00

LDT (hours)

To

luen

e, N

Ox-

O3

con

c (p

pm

)

-20

-10

0

10

20

Par

ticl

e m

assc

on

c (

g/m

3)

TSP

O3

Toluene

TotNO3

NO

NO

2

Toluene SOA behavior Toluene SOA behavior within an atmospheric HC within an atmospheric HC

mixturemixture

SOASOA from 0.1 ppmV from 0.1 ppmV toluene+0.1ppm NOx toluene+0.1ppm NOx

w/wo 3ppmC HC mixture w/wo 3ppmC HC mixture

0

5

10

15

20

25

8:00 10:24 12:48 15:12 17:36

g/m

3

Without HC mix

SOASOA from terpene mixturesfrom terpene mixtures

0.05 ppmV 0.05 ppmV -pinene-pinene0.02 ppmV d-0.02 ppmV d-

limonenelimonene0.05 ppm NO0.05 ppm NOXX

SOASOA from terpene mixturesfrom terpene mixtures

042006S

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

6.0 7.5 9.0 10.5 12.0 13.5 15.0

EDT (Hour)

NO

/NO

2 C

on

c (

pp

m)

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

O3

Co

nc

(p

pm

)

NO dataNO2 dataNO simNO2 simO3 dataO3 sim

SOA SOA from terpene mixturesfrom terpene mixtures

0.00

0.01

0.02

0.03

0.04

0.05

0.06

6.0 7.5 9.0 10.5 12.0 13.5 15.0EDT (Hour)

AP/

d-L

im c

onc

(ppm

)

0

20

40

60

80

100

120

TSP

Con

c (u

g/m

3)

A-P

d-lim

a-P sim

d-Lim

TSP d=1.2

TSP Sim

042006S

How do we represent changing How do we represent changing particle size distributions??particle size distributions??

Need to integrate particle sizes into our Need to integrate particle sizes into our mechanismsmechanisms

0.E+00

1.E+03

2.E+03

3.E+03

4.E+03

1 10 100 1000

diameter, nm

#/cc

7.5 nm particles

0.E+00

1.E-03

2.E-03

3.E-03

4.E-03

1 10 100 1000

minutes

con

c

pinald

pinacid

diacid

oxypinald

oxypinacid

pinalic

pinald-PAN

OH-AP-NO3

15 nm particles

0.E+00

5.E-04

1.E-03

2.E-03

2.E-03

3.E-03

1 10 100 1000

minutes

con

c

pinald

pinacid

diacid

oxypinald

oxypinacid

pinalic

pinald-PAN

OH-AP-NO3

10 100 10001

1 10 100 1000nm

minutes

mas

sm

ass

7.5 nm particles

15 nm particles

Model Simulations Model Simulations of UNC of UNC

Toluene/NOx Toluene/NOx ExperimentsExperiments

O3-pinene

10 ppbV 10 ppbV -pinene +40 ppb O-pinene +40 ppb O33

610 17 29 50

85

146

20.5

3 hr

s

02468

1012

14

Nu

mb

er o

f P

arti

cles

/cc

Particle size (nm)

South Chamber particle distributions

20.53 hrs

20.83 hrs

6 8

12

17

24

35

50

71

10

2

14

6

20

9 20.88 hrs

0

20

40

60

80

Nu

mb

er

of

Pa

rtic

les

/cc

Particle size (nm)

South Chamber nucleaton particle distributions

20.88 hrs

20.93 hrs

20.83 hrs

20.98

new particles/cc = 3x107x -pinene reacted1.77

# stable nuclei = Ax10[reacted organic] x [H2SO4]n

Gas phase Sulfuric Acid and nucleation

# stable nuclei = Ax10[reacted organic] x [H2SO4]n

Final point:How important is Isoprene in

the formation of SOA?

C=C-C=CC=C-C=CH

HCH3

H

HH

Primary and SecondaryContributions to Ambient PM in the Midwestern United States

Lewandowki, and Schauer, et al., ES&T 2008

Sesquiterpenes (C15H24)

On a reacted mass basis,On a reacted mass basis, b- b-caryophyllene and a-humulene caryophyllene and a-humulene have much higher have much higher aerosolaerosol potentials than monoterpenes potentials than monoterpenes

(Griffin et al., 1999).(Griffin et al., 1999).

Yield-carophyllene-carophyllene 17 - 62 17 - 62 %%-humulene-humulene 20 - 67 20 - 67d-limonened-limonene 6 - 23 6 - 23-pinene-pinene 2 - 8 2 - 8-pinene-pinene 4 - 13 4 - 13

# stable nuclei = Ax10[reacted organic] x [H2SO4]n

We do not have an Isoprene in the formation of SOA?

Unique SOA poly-ols from isoprene Unique SOA poly-ols from isoprene reaction with OH reaction with OH

(Magda Claeys et al. Science, 2004)(Magda Claeys et al. Science, 2004)