Modelling urban pollution within the UK scale integrated assessment model, UKIAM Helen ApSimon, Tim...

Modelling urban pollution within the UK scale integrated assessment

model, UKIAM

Helen ApSimon, Tim Oxley and Marios Valiantis

UK Centre for Integrated Assessment Modelling

Imperial College London

UKIAM- a national scale model including urban areas

Modelling urban background concentrations-PPM model

Illustrations for particulate matter PM10

Modelling NO2, and urban ozone deficit

Current developments including roadside concentrations in relation to AQ limit values

ATMOSPHERIC MODELLING:

Imported: EMEP

+ ASAM tool

FRAME(CEH)

PPM(Imperial)

BRUTAL (Imperial)

UK Integrated Assessment Model: UKIAM

UK SOURCES

Projected UK emissions:

NETCEN

ENTEC,CEH

Abatement options and costs

ENTEC

NARSES

SHIPPING

ENTEC

ENVIRONMENTAL CRITERIA:

Ecosystems: CEH

Human health &

Urban air quality

UKIAM->Integrated analysis of either specified scenarios, or optimised selection of abatement options converging to achieve environmental criteria at least cost (Imperial)

PPM receptor oriented model : urban back-ground->UK scale

5 x 5 km grid

Elevated source

Volume source to 100 m

10 m high

Gaussian plume

Uniform over mixing layer

< deposition /depletion >

SUPERIMPOSED BACKGROUND- other sources/imported

ROADSIDE INCREMENT-

BRUTAL model

MODELLING COMPONENTS IN UKIAM for UAQ

Chemical conversion for NO2

k

Stedman (UK NOx data for 1996) 33

Carslaw NOx data for LAQN for 1998 “ “ “ “ 1997 “ “ “ “ 1996

25

26 24

IIASA – PM in London for 2001(background sites only; R2= .9116)

24

PPM model: contribution from home square 5x5 km

29-33

Comparison empirical modelling C= k.E +X

E= emission kT in 5x5km gridsquare, C g/m3

PM10 Modelling

Superimposes:

primary contribution due to UK sources using PPM (PWC 2.2)

+ imported primary PM cont. from EMEP modelling (PWC 0.8 ug.m3)

PLUS secondary PM, SIA

( NB no SOA)

PLUS additional background of 5 to 9 ug/m3 for rural and city populations respectively

(natural, sea salt, road resusp. Intermittent sources)

NB No TEOM correction applied

Urban background PM10 concentrations- London

2000 2020

UKIAM :background NO2 Satellite data

Simple treatment chemistry NO, O3, NO2

i) model total NOx = NO + NO2

ii) total oxidant O3b + NOx = O3 + NO2

111) mean rate dissociation ~J[NO2]

____________________________ = F

oxidation NO->NO2 ~ k,[NO], [O3]

If F=1 same as photo-stationary state.

Generates quadratic equation for NO2

Comparison of predicted NO2 by PPM and Jenkin

NNPM with Fit 1 NNPM with Fit 2

Fit 1 & Fit 2 @ 9.48% Pry NO2 & 35.7ppb O3

PPM @ 10% Pry NO2 & 35ppb O3

0

10

20

30

40

0 20 40 60 80 100

NOX ppb

NO2 p

pb

0

10

20

30

40

50

60

0 50 100 150 200 250

NOX ppb

NO2 p

pb

Background sites 2002 2005

Bexley Bloomsbury Brent Eltham Hackney Lewisham North Kensington Southwark1 Teddington Tower Hamlets1

Wandsworth2 West London PPM @ 5% pry NO2 & 35ppb O3

0

5

10

15

20

25

30

35

40

0 20 40 60 80 100

NOX ppb

NO2

ppb

05

101520253035

0 20 40 60 80 100

NOX ppbNO

2 ppb

Reducing urban NOx emissions -> local increase in urban ozone concentrations.

Estimate from change in secondary NO2 and corresponding ozone deficit

Urban ozone decrement over London: 2000 and 2020

2000 2020

ASAM- European scale (50km)

UKIAM- UK scale (5km)

BRUTAL- Background Road & Urban Transport modelling of Air quality Limit Values->

Superimpose road-side on background @ 1x1 km

Road network + traffic data-> traffic emissions individual roads and gridded

Pop. Data -> urban areas/roads (canyons etc)