Source apportionment of PM in the ADMS model

David Carruthers

Workshop on Source Apportionment of Particulate Matter

 

Imperial College London

Friday, 23 April 2010

Contents

• Modelling methodology• London • Marylebone Road• Resuspension• Other

• Models all source groups within the urban area – typically hour by hour calculation

• Explicitly models major road sources, major industrial sources. Includes street canyon model

• Other sources modelled as grid sources (e.g.1km* 1km

• Regional pollution from rural monitoring sites or from larger area model (e.g. WRF/CMAQ or Pre’vair/Chimere)

Model ADMS-Urban Model Methodology

0

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Measured concentration (µg/m³)

Mo

del

led

co

nce

ntr

atio

n (

µg/m

³)

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70

0 10 20 30 40 50 60 70

Measured concentration (µg/m³)

Mo

del

led

co

nce

ntr

atio

n (

µg/m

³)

Model verification at AURN Sites – PM10 & PM2.5

London (2001)

PM10

PM2.5

Annual Mean 90.4th percentile

Measured Modelled

Marylebone Road 32.0 32.8

Bloomsbury 17.1 19.2

(a) Total PM10 (b) Traffic (Major and minor roads)

(c) Rail (d) Shipping

(e) Domestic Gas (f) Commercial Gas

(g) Industrial (h) Other

PM10 (µg/m³)> 3529 - 3527 - 2925 - 2723 - 2510 - 235 - 101 - 50.5 - 10.1 - 0.50 - 0.1

Contributions of source groups to total PM10 concentrations 2010

PM10 (µg/m³)> 3529 - 3527 - 2925 - 2723 - 2510 - 235 - 101 - 50.5 - 10.1 - 0.50 - 0.1

(a) Major Roads (b) Other Roads

(c) Car (d) Taxi

(e) Bus and Coach (f) LGV

(g) Rigid HGV (h) Articulated HGV

Source apportionment

of PM10 from vehicle exhaust emissions 2010

Source apportionment of PM10 traffic emissions. Mean

all London AURN sites

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0.2

0.4

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0.8

1

1.2

1.4

1.6

1.8

2

Tota

l exh

aust

CarTa

xiLG

V

Rigid

HG

V

Articu

late

d HG

VBus

Resus

pens

ion e

tc

An

nu

al

av

era

ge

PM

10

fro

m t

raff

ic

at

AU

RN

sit

es

(µ

g/m

³)

20102020

Car38%

Taxi11%

LGV31%

Rigid HGV10%

Articulated HGV4%

Bus6%

0

25

50

75

100

125

1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361

Day

PM

10 c

on

cen

trat

ion

(µg

/m³)

Measured

Modelled

Measured ModelledAnnual average (µg/m³) 43.8 43.4No. exceedences of 50µg/m³ 114 9490.41st percentile of daily averages (equivalent to 35 exceedences)

64.1 57.0

Marylebone Road 2001 – Modelled time series and Number of exceedences of limit values

Rural background47%Major Road

39%

Rural background

Urban 'coarse'

Roadside 'coarse'

Major Road

Minor road

Industrial

Domestic

Other

Source contributions to modelled annual average PM10 concentration

HGV21%

LGV28%

Taxi25%

Car17%

Bus5%

M'cycle4%

Motorcycle

Car

Taxi

LGV

Bus

HGV

Source contribution of vehicle types

Marylebone Road

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90

100

1 51 101 151 201 251 301 351

Day

24-h

ou

r av

erag

e P

M10

co

nce

ntr

atio

n (

µg/m

³)

Other

Industrial

Domestic

Minor road

Major road

Rural background

Urban coarse

Roadside coarse

Modelled source contributions to modelled daily average PM10 concentrations, Marylebone Road 2001

0

10

20

30

40

50

60

70

80

90

100

1 11 21 31 41 51 61 71 81 91

24-h

ou

r av

erag

e P

M10

co

nce

ntr

atio

n (

µg/m

³) Other

Industrial

Domestic

Minor road

Urban 'coarse'

Roadside 'coarse'

Major road

Rural background

0

10

20

30

40

50

60

70

80

90

100

1 11 21 31 41 51 61 71 81 91

24-h

ou

r av

erag

e P

M10

co

nce

ntr

atio

n (

µg/m

³)

Other

Industrial

Domestic

Minor road

Urban 'coarse'

Roadside 'coarse'

Rural background

Major road

Source contributions to exceedences of the 50µg/m³ objective value, ordered by background contribution and major road contribution

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60

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Total concentration (µg/m³)

So

urc

e c

on

trib

uti

on

(µ

g/m

³)

Rural background

Major road

Major road and background contribution compared to total concentration

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60

0 10 20 30 40 50 60

Rural background (µg/m³)

Ma

jor

roa

d c

on

trib

uti

on

(µ

g/m

³)

Comparison of major road and rural background concentrations

Non-Exhaust Emissions of PM

• DEFRA Project –TRL, University of Birmingham, CERC

• Review of methodologies for tyre wear, brake wear and road wear

• Focus resuspension

Non-exhaust study- Resuspension

• Estimated from measurements at Marylebone Road & Bloomsbury.

ETOTAL, NON-EX = ETYRE + E BRAKE + EROAD + ERESUSP

• ETYRE, EBRAKE & EROAD determined using several methods

– Existing EMEP method– RAINS database– CEPMEIP database

• PM2.5 = exhaust (94%), PM2.5-10 = non-exhaust + exhaust (6%)

• ERESUSP dominated by HDV 116mg/km,(LDV 0.02mg/km)

x

NOPM NO

PMEE

x

1010

Non-exhaust study - dispersion modelling sites

• 4 TRAMAQ sites (Birmingham Selly Oak, Park Lane, Elephant and Castle, High Holborn)

– PM10 and PM2.5

– Kerbside and background– Chemical component data available

• 9 London DEFRA sites – 2 with PM10 and PM2.5

– 7 with PM10 only

0

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7000

PM10 PM2.5 PMcoarse

Em

issi

ons

(ton

nes/

year

)

Other sourcesExhaustTyreBrakeRoad wearResuspension

Non-exhaust studyRoad Traffic Emission totals 2002 London

Traffic source contribution to modelled concentrations (London 2002)

PM10

PM2.5

Exhaust55%

Tyre11%

Brake14%

Road wear10%

Resuspension10%

Exhaust76%

Tyre9%

Brake8%

Road wear7% Exhaust

14%

Tyre10%

Brake29%

Road wear15%

Resuspension32%

PMcoarse

0

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50

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Measured

Mod

elle

d

Defra (resuspension 1A)Defra (resuspension 2A)TRAMAQ Roadside (resuspension 1A)TRAMAQ Roadside (resuspension 2A)TRAMAQ Background (resuspension 1A)TRAMAQ Background (resuspension 2A)Modelled = ObservedModelled within +/- 30% of observed

Non-Exhaust studyDispersion modelling - PM10

Annual average PM10 concentrations

Annual average PM2.5 concentrations

0

10

20

30

40

0 10 20 30 40

Measured

Mod

elle

d

DefraTRAMAQ RoadsideTRAMAQ BackgroundModelled = ObservedModelled within +/- 50% of observed

Non Exhaust StudyDispersion modelling - PM2.5

0

10

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40

50B

exl

ey

Bre

nt

A3

Hill

ing

do

n

Ha

rin

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y R

oa

dsi

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N K

en

sin

gto

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Ca

md

en

Ma

ryle

bo

ne

Rd

Blo

om

sbu

ry

EC

Ro

ad

sid

e

HH

Ro

ad

sid

e

PL

Ro

ad

sid

e

SO

Ro

ad

sid

e

EC

Ba

ckg

rou

nd

HH

Ba

ckg

rou

nd

PL

Ba

ckg

rou

nd

SO

Ba

ckg

rou

nd

Co

nce

ntr

atio

n (

µg

/m³)

MonitoredModelled:BackgroundOther sourcesExhaustTyreBrakeRoad wearResuspension

Non-exhaust studyDispersion modelling - source apportionment

Annual average PM10

concentrations

Non-exhaust study: Resuspension – Uncertainty

Dependence on wind speedVariation of hourly median resuspension at Marylebone Road with wind direction at Heathrow, 2001

y = -0.0816x2 + 3.2982x + 5.0374

R2 = 0.8223

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50

0 2 4 6 8 10 12 14 16 18

Wind speed at Heathrow (knots)

Res

uspe

nsio

n (g

km

-1 h

-1)

Non-exhaust study Resuspension Uncertainty - source properties

E x h a u s t (1 .5 m fo r h e a v y , 1 m

fo r lig h t)

B ra k e w e a r: (1 m fo r h e a v y , 0 .7 5 fo r lig h t)

T y re w e a r (0 .5 m )

R o a d w e a r (0 .5 m )

R e s u s p e n s io n (0 .5 m )

R e s u s p e n s io n (0 .5 m )

Singapore Harrison Chemical Speciation model based on

chemical sampling vs PM measurements

JI YS CS JI YS CS0

10

20

30

40

50

60

PM10-2.5

PM2.5

Minerals

NaCl

NaNO3

NH4NO3

(NH4)2SO4

CaSO4.2H2O

Elemental carbon

Organic carbon

µg

/m³