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

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0 20 40 60 80 100

NOX ppb

NO2 p

pb

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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

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0 20 40 60 80 100

NOX ppb

NO2

ppb

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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)