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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)
!" (N
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)
!" (N
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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9:;!-71?!@%5A!0!3%5!-3!=%)78!8050!3(-.!5(08%5%-207!9:;!)B/)(%.)251!(%'.!1505)1!@%5A!5A)!1.077)(!1=.>-71!""M!
1A-@%2&!5A)!/0(5%67)!)N-7N%2&!035)(!8%7'5%-2C!O06A!1.077!1=.>-7!()/()1)251!-2)!9GP9!""Q!
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