Institute for Chemical Process and Environmental Technology

Helmut Roth, Weimin Jiang,

Dazhong Yin, and Éric Giroux

CMAQ Nucleation Algorithms and their impact on PM modeling results

in the Lower Fraser Valley

National Research Council of Canada

Ottawa, Canada

Institute for Chemical Process and Environmental Technology

• Introduction

• Nucleation Rates

• Impact on PM

• Conclusions & future work

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IntroductionIntroduction

• Episode: Pacific ’93 (1993 Jul 31 – Aug 07)

• Emissions: SMOKE, Giroux, É. et al

• Meteorology: MM5, Yin, D. et al

• Domain

• Nucleation Algorithms

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Horizontal domainsHorizontal domains

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Nucleation parameterizations & algorithmsNucleation parameterizations & algorithms

• HK98: Harrington and Kreidenweis (1998) Fully coupled equations of 2-mode 2-moment model implemented in aero2

• KLPx: Kulmala et al (1998) Equations of classical nucleation theory Implemented in aero2, aero3: KLP2, KLP3 Differences in number distribution, density

• sulphuric acid – water system

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Nucleation rates: Nucleation rates: modeling modeling

C M A Qa ero_ noop

em is

m et

o ther

[S U L A E R ]C T M _ C O N C

dtd river

a ero2nu cl on ly

H K 9 8 | K L P 2 | K L P 3

nu clea tionra tes

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11stst layer domain-average number rates layer domain-average number rates

Layer1 mean [number] production rate

1.0E+00

1.0E+03

1.0E+06

1.0E+09

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

Time of day, 1993 Jul 31 0:00 to Aug 08 0:00, PDT

nu

clea

tion

rat

e (#

/ m

3 / s)

1.0E-10

1.0E-07

1.0E-04

sula

er c

onc

(pp

mV

)

HK98 NUMi

KLP3 NUMi

meanL1 sulaer

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11stst layer domain average ASO4I rates layer domain average ASO4I rates

Layer1 mean [ASO4i] production rate

1.0E-15

1.0E-12

1.0E-09

1.0E-06

1.0E-03

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

Time of day, 1993 Jul 31 0:00 to Aug 08 0:00, PDT

m g /

m3

/ s

HK98 ASO4i

KLP2 ASO4i

KLP3 ASO4i

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11stst layer number rate statistics layer number rate statistics

peak cell

(Aug05 13:00) peak domain average

(Aug05 14:00) episode average

HK98 5.15e09 6.30e07 16.2e05 KLP2 10.95e09 2.82e07 2.12e05 KLP3 10.95e09 2.82e07 2.12e05

all maxima occur in cell (17,8)

Neptune Beach

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Time-average, 1Time-average, 1stst layer number rate layer number rate

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Correlation at time of peak nucleationCorrelation at time of peak nucleation

KLP3 vs HK98 #

1.00E+00

1.00E+02

1.00E+04

1.00E+06

1.00E+08

1.00E+10

1.00E+06 1.00E+07 1.00E+08 1.00E+09 1.00E+10

HK98

KL

P3

> m

in

KLP3 #

r2=0.9

Aug 05

13:00

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Impact on PM concentrations: Impact on PM concentrations: model runsmodel runs

• Common inputs

• Full gas phase calculations

• All aerosol processes

• Different nucleation algorithms:NOOP HK98 KLP2 KLP3

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Number concentrationNumber concentration

0.0E+00

2.0E+09

4.0E+09

6.0E+09

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

Time of day

[nu

mb

er]

(m

-3)

Noop

HK98

KLP2

KLP3

i-mode

PM2.5

First layer mean PM2.5 [number]

0.0E+00

2.0E+09

4.0E+09

6.0E+09

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

par

ticl

es /

m3

Noop # 25

HK98 # 25

KLP2 # 25KLP3 # 25

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Time-average, 1Time-average, 1stst layer NUMATKN layer NUMATKN

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Sulphate (ASO4) concentrationSulphate (ASO4) concentration

0.00

0.05

0.10

0.15

0.20

0.25

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

Time of day

[AS

O4

I] (

ug

m-3

)

Noop

HK98

KLP2

KLP3

0.4

0.8

1.2

1.6

2.0

0 12 0 12 0 12 0 12 0 12 0 12 0 12 0 12 0

NoopASO4

HK98ASO4

KLP2ASO4

KLP3ASO4

PM2.5

i-mode

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Time-average, 1Time-average, 1stst layer ASO4I layer ASO4I

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Main ConclusionsMain Conclusions

• KLP2 and KLP3 results very similar

• KLPx had greatest individual cell rate.

• HK98 had greatest average rates.

• HK98 more responsive to [SULAER] fluctuations.

• HK98 increases number concentration over NOOP; KLPx does not.

• No increase in PM2.5 SO4 mass over NOOP.

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Future workFuture work

• Impact of nucleation algorithms on model performance using ambient number concentration data

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AcknowledgementsAcknowledgements

• U.S. EPA: CMAQ source code

• Environment Canada: emissions and met data, ambient PM mass data

• Program of Energy Research and Development (PERD) in Canada: funding support

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Thank you !Thank you !

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Time-average, 1Time-average, 1stst layer mass rate layer mass rate

n u cle a t io n _ K L P2 /n u cle a t io n _ K L P3 /n u cle a t io n _ H K 9 8 /n u cle a t io n _ n o o p

a e ro pro c

a e ro _ driv e r

a e ro s te p m o de _ m e rg in g /m o de _ m e rg in g _ n o o p

PM e m is /PM e m is _ n o o p

1

1

aer o _ d ata

1

c o n s t_ d ata

5

air _ d ata

4

aer o em is _ d a ta

3

p r ec u r s r _ d ata

2

in o re ql_ e ql3 /in o re ql_ e ql3 _ n o o p

co n d_ n u cl/co n d_ n u cl_ n o o p

S O A _ Pa n dis /S O A _ O du m /S O A _ S ch e ll/

S O A _ n o o p

co a g u la t io n /co a g u la t io n _ n o o p

o de _ s o lv e r s ize v a r

s ize v a r

1

1

1

1 1

1

1

1

1

2 3 4

5

2

2

2

5

3 5

2

4

4

44

4

5

5

5

5

5

5

5

2

5

5