Source apportionment of PM in the ADMS model

David CarruthersWorkshop on Source Apportionment of

Particulate Matter 

Imperial College LondonFriday, 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

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Measured concentration (µg/m³)

Mod

elle

d co

ncen

trat

ion

(µg/

m³)

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Measured concentration (µg/m³)

Mod

elle

d co

ncen

trat

ion

(µg/

m³)

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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0.8

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1.2

1.4

1.6

1.8

2

Total

exha

ust

CarTa

xiLG

V

Rigid HGV

Articulat

ed H

GVBus

Resus

pens

ion etc

Ann

ual a

vera

ge P

M10

from

traf

fic

at A

URN

site

s (µ

g/m

³)

20102020

Car38%

Taxi11%

LGV31%

Rigid HGV10%

Articulated HGV4%

Bus6%

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75

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125

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

Day

PM10

con

cent

ratio

n (µ

g/m

³)

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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80

90

100

1 51 101 151 201 251 301 351

Day

24-h

our a

vera

ge P

M10

con

cent

ratio

n (µ

g/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

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50

60

70

80

90

100

1 11 21 31 41 51 61 71 81 91

24-h

our a

vera

ge P

M10

con

cent

ratio

n (µ

g/m

³) Other

Industrial

Domestic

Minor road

Urban 'coarse'

Roadside 'coarse'

Major road

Rural background

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10

20

30

40

50

60

70

80

90

100

1 11 21 31 41 51 61 71 81 91

24-h

our a

vera

ge P

M10

con

cent

ratio

n (µ

g/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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Total concentration (µg/m³)

Sour

ce c

ontr

ibut

ion

(µg/

m³)

Rural background

Major road

Major road and background contribution compared to total concentration

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60

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Rural background (µg/m³)

Maj

or ro

ad c

ontri

butio

n (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 NOPMEE

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

Emis

sion

s (to

nnes

/yea

r)

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

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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

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Measured

Mod

elle

d

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

Non Exhaust StudyDispersion modelling - PM2.5

0

10

20

30

40

50B

exle

y

Bre

nt A3

Hill

ingd

on

Har

inge

y R

oads

ide

N K

ensi

ngto

n

Cam

den

Mar

yleb

one

Rd

Blo

omsb

ury

EC

Roa

dsid

e

HH

Roa

dsid

e

PL

Roa

dsid

e

SO

Roa

dsid

e

EC

Bac

kgro

und

HH

Bac

kgro

und

PL

Bac

kgro

und

SO

Bac

kgro

und

Con

cent

ratio

n (µ

g/m

³) Monitored

Modelled: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 + 5.0374R2 = 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 xh 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

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60

PM10-2.5

PM2.5

Minerals

NaCl

NaNO3

NH4NO3

(NH4)2SO4

CaSO4.2H2O

Elemental carbon

Organic carbon

µg/m

³