Atmospheric Processing of OrganicParticulate Matter:

Formation, Properties, Long-RangeTransport, and Removal

Neil M. Donahue, Spyros N. Pandis, Allen L. Robinson

Peter J. Adams, Cliff I. Davidson

Carnegie Mellon UniversityCenter for Atmospheric Particle Studies

Atmospheric Science Progress Review Meeting22 Jun 2007

RTP, NC

1

The Center for Atmospheric Particle Studies

2

Organic Aerosol

Vapor Pressure

Precursor

VolatileProducts

PrimaryEmission

POA SOAfixed

yield

Not quite state of the art, common in models...

3

Organic Aerosol

Vapor Pressure

SOAPrecursor

VolatileProducts

PrimaryEmission

POA p1 p2

α1α2

semivolatile products(Odum 2-product model)

State of the art, in some models...

4

Organic Emissions Processing

Vapor Pressure

Precursor

Product Product Product

Gen

erat

ion

#

5

Continued Processing

Vapor Pressure

Precursor

Product Product Product

Gen

erat

ion

#

Product Product Product Product

t~1 dayt~1 day ?

6

How Far Does it Go??

Vapor Pressure

Precursor

Product Product Product

Gen

erat

ion

#

Product Product Product Product

t~1 dayt~1 day ?

mean particle age ~ 7 days?

7

α-pinene + Ozone

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!"*+/01-234567*)610803*9288*:12;14??4= et al.*@!AAAB

'0;C61 et al.*@#""!BD168

Partitioning at Specified COA in Solution

!3 !2 !1 0 1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

log10 C* (µg m!3)

! (A

eros

ol F

ract

ion)COA = 1.0 µg m

!3

ξi =1

1 +C∗i

COA

9

The Volatility Basis Set

!3 !2 !1 0 1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

log10 C* (µg m!3)

! (A

eros

ol F

ract

ion)COA = 1.0 µg m

!3

C∗i ={0.01,0.1,1,10,100,1000,104,105,106

}µgm−3

[Donahue et al., ES&T, 2006]10

α-pinene and the Basis Set

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α-Pinene + Ozone Partitioning

0.01 0.1 1 10 100 1000 10^4 10^5 10^60

1

2

3

4

5

6

7

8

9

10

11

C* (µg m!3)

Org

anic

Mas

s (µ

g m!3

) COA = 1.0 µg m!3

a) Low !!pinene (26 µ g m!3)

0.01 0.1 1 10 100 1000 10^4 10^5 10^60

20

40

60

80

100

120

140

160

180

200

C* (µg m!3)

Org

anic

Mas

s (µ

g m!3

) COA = 100.0 µg m!3

b) High !!pinene (468 µ g m!3)

Partitioning changes with mass loading: x18 total loading = x100 COA.Most of the OA compounds at 100µgm−3 are not in the particles at 1.

[Donahue et al. in prep]

12

α-Pinene + Ozone Mass Balance

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C10=1

C10O4 = 1.4

O3+

O

O

OOH

100 ppt10-7 torr

1 atm760 torr

Mass balance for ‘nominal product’ demands ξmax =∑

i αi ' 1.4.

13

α-pinene + Ozone: UV (no NOx)

10!2 10!1 100 101 102 1030

0.05

0.1

0.15

0.2

0.25

0.3

COA (µg m!3)

!" (N

orm

ali5e

7 Ae

roso

l Mas

s Fr

actio

n) (d)Presto et al. [2005]20 June 2005low!NOx fitUV fit

α′i = {.004, 0, .05, .09, .12, .18, ...}↓ UV

α′i(UV) = {.004, 0, .02, .08, .12, .18, ...}

[Presto et al., ES&T, 2005a]14

α-pinene + Ozone: VOC:NOx

10!2 10!1 100 101 102 1030

0.05

0.1

0.15

0.2

0.25

0.3

COA (µg m!3)

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orm

ali5e

7 Ae

roso

l Mas

s Fr

actio

n) (c)# $ 0.># $ 0.1low!NOx fit

α′i(HO2) = {.004, 0, .05, .09, .12, .18, ...}↓ NOx β = (VOC : NOx)0/10, (VOC : NOx)0 < 10

α′i(NOx) = {0, 0, 0, 0, .15, .2, ...}

[Presto et al., ES&T, 2005b]15

RO2 Fate

hv (+ OH)

Ox

(+ NO2)

NO HO2

terpene

RO2

ROONO ROOH

RORONO2

β

Bottom line – tie SOA module into gas-phase RO2 chemistry:

{α} = β {α}low−NOx + (1− β) {α}high−NOx

16

α-Pinene + Ozone T Dependence

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

-10 -5 0 5 10 15 20 25 30 35 40 45

Temperature ( oC)

SO

A M

ass

Fra

ctio

n

Low (7.3-8.5 ppb)

Medium (14.3-17ppb)

High (33-50ppb)

Saathoff et al. [2004] (17 ppb)

Upturn in SOA between 15 and 0oC.

[Pathak et al., JGR, 2007], [Stanier et al., ACPD, 2007]17

α-Pinene + Ozone Total Mass 300 K

10!2 100 102 104 106 1080

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

COA (µg m!3)

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orm

alize

d Ae

roso

l Mas

s Fr

actio

n)

Dark green yields are guesses – total is constrained.

18

α-Pinene + Ozone Total Mass 243 K

10!2 100 102 104 106 1080

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

COA (µg m!3)

!" (N

orm

alize

d Ae

roso

l Mas

s Fr

actio

n)

Products shift left by 2.5 orders of magnitude.

(Note – [Saathoff et al. IAC 2006] saw ∼1 AMF at 100-200 µgm−3 and 243 K.)

19

α-Pinene + Ozone Total Mass 350 K

10!2 100 102 104 106 1080

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

COA (µg m!3)

!" (N

orm

alize

d Ae

roso

l Mas

s Fr

actio

n)

Products shift right by 2.5 orders of magnitude.

20

α-Pinene + Ozone Thermodenuder

Given time, all SOA evaporates at 70C.

[An et al., AS&T, 2007]21

α-Pinene + Ozone Thermodenuder

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transfer function (16 sec)

transfer function (1.6 sec)

Denuding is a function of evaporation timescales.

[Pierce et al., in prep, 2007]22

α-pinene + O3 Dilution0.4

0.3

0.2

0.1

0.0

No

rmalized

AM

F

10 100

COA ( g m-3

)

Chamber Dilution Experiments: Experiment # 1: DR = 3, then 8; Total Time: 1 hr

Experiment # 2: DR = 80; Total Time: 4.8 hrs

Experiment # 3: DR = 31; Total Time: 3.7 hrs

!!Yield Experiment

Curve

Dilution Sampler Data

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1602!0(1!-2!,:;!()/()1)25!""R!

'26)(50%25=!8')!5-!@07747-11)1!%2!5A)!6A0.>)(S!;G$!)((-(!>0(1!0()!>01)8!-2!)15%.05)8!""T!

'26)(50%25=!%2!5A)!=%)78!/0(0.)5)(%F05%-2C!!""U!

Generate high SOA and then flush 90% of chamber air.Particles shrink slowly to expected size. [Grieshop et al., GRL 2007]

23

Implications: Vapors

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Condensed Phase

Vapor Phase

The mass not seen in the particles is in the gas phase, very low vapor pressure.

24

Limonene + Ozone Mass Balance

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@6.2?8?8A+52B!1)C+,943D0

E:>6.4>89+F434.8>83:

+F434.8>83:

G38=H3:23+I254>656>J

+=H3I8

#!F6?8?8+K4:6:!:8>+L6>

O

O

O

OOH

HOO

C10=1C9O7 = 1.6

O3+

D-limonene + O3 makes more SOA than α-pinene (2nd generation of oxidation).

[J. Zhang et al., JPC, 2006]25

Implementing Basis Set in PMCAMx

July 2001 Biogenic SOA

Old ∼constant yield New Basis set yields Multi-generation aging

New basis set parameters cause most SOA to evaporate at ambient COA.Adding aging (gas-phase OH oxidation) can generate lots of SOA.Aging parameters are not yet known (these are a reasonable guess).

[Lane et al. in prep]

26

Conclusions Picture

C*(µg m3)

log

Emiss

ions

10910610310010-3

biogenic

anthropogenic

‘POA’ condensed at ambient COA

‘POA’ condensed at source

log

Conc

entra

tion

Fresh

Aged ‘Traditional’ SOA

‘New’ SOA

Het Aging

OOA Decomposition

HOA

OOA

0:11:1

0:11:1

27