SOURCE APPORTIONMENT ofPARTICULATE MATTER

Imperial College23rd April 2010

APRIL:Air Pollution Research in London

Which Sources?Emissions?

What chemical composition?

SO4,NO3,NH4, C, Fe etc

ConcentrationExposure

Where from?nearest road

other UK sourcesoutside UK?

SOURCE APPORTIONMENT of PM in INTEGRATED ASSESSMENT

MODELLING at IMPERIAL COLLEGE

Tim Oxley, Helen ApSimon, Ayman Elshkaki

Imperial College London

1. PM modelling in UK IAM: uses data and work from several other modellers: aimed at predicting future concentrations and exposure

2. Emissions

3. Primary PM concentrations

4. Secondary SIA (SO4, NO3 and NH4) concentrations

5. Other contributions to PM10 & PM2.5

6. Trends 2010 to 2020

UK integrated assessment model, UKIAM

Aim: Assess future scenarios and abatement measures in relation to setting of national emissions ceilings for 2020-> UK air quality, ecosystem protection and GHG emissions

Pollutants: SO2, NOx, NH3, PM10, PM2.5, CO2, N2O, CH4

Detailed sub-model BRUTAL for road transport -> roadside concentrations + 1x1 km background concentrations

Emissions UK sources based on NAEI (point or 1x1 km)

Contributions imported from other countries and shipping

shallow canyonssuburbs

deep street canyons dense pop. city centreOpen roads

rural

Road-side increment NOx, primary PM

Emissions each UK road link NOx,PM,CO2,N2O (iMOVE)

Traffic flow, ave speed, vehicle mix+ data base emission factors

Superimpose on background concentration NOx, primary PM from UK sources

Grid 1x1 km emissions road transport

Other UK emissions PPM model

Add long-range secondary PM: & primary NOx and PM contributions imported (including shipping) and from other sources

Calculate NO2 concentrations from total NOx allowing for a frac.

BRUTAL (UKIAM)-> modelling of urban air quality

EMISSIONS PRIMARY PM (UEP32 scenario) 2010 2020

(ktonnes) PM10 PM2.5 PM10 PM2.5

Power 4.5 3.0 4.1 2.7 Dom 16.4 9.9 14.1 8.5 Industry 42.9 24.6 43.6 24.9 Road Trans 25.5 20.1 15.5 12.4 Off-road 9.4 7.4 3.3 2.7 Agric/Nat. 15.7 6.7 15.7 6.7______________________________________________________________

Total UK 114.0 71.7 96.3 57.9

EU 27 (inc UK) 1964 1648

NB IIASA total PM2.5 agrees very well but sources covered differ ? Are there missing sources of PM e.g. from cooking

PRIMARY PM CONCENTRATIONS (PPM model)Small contributions imported and from shipping

PM 2.5 in 2010

Sources (kt) UEP32 scenario

Power 3.0Domestic 9.9Industry 24.6Roads 20.1Off-road 7.4Agri/nat. 6.7

Total UK 71.7

PRECURSOR EMISSIONS Secondary Inorganic Aerosol

kt 2010 2020UEP32 scenario SO2 NOx SO2 NOxPower 138 296 71 144Domestic 16 93 9 67Industry 181 229 167 223Roads 0.6 339 0.6 124Off-road 11 153 12 73___________________________________________________Total UK 346 1110 259 632

EU27 5928 8749 4424 6339

UK NH3 307kt in both 2010 and 2020 (IPPC not included)EU27 NH3 4212 kt in 2010 and 4124 in 2020

UKIAM : use of pre-calculated source-receptor footprints each source->rapid scenario assessment

Take reference case and estimate effect of reducing emissions from a source by specified amount on concentrations/deposition-> multiply effect for bigger/smaller changes in emission

More complicated for secondary PM with interacting pollutants- e.g. need to allow for effect of NH3 on NO3 concentrations.

CONCENTRATIONS OF SIA= SO4+NO3+NH4FRAME andEMEP models-

SIA components in 2020; based on FRAME/EMEP models

Frame NH4 SO4 NO3 totalPWM 0.74 mg/m3 0.82 fine 1.46 3.0 (PM2.5) all 1.71 3.24 (PM10)

EMEP implies larger proportion imported than FRAME-> total SIA 4.5 mg/m3

OTHER CONTRIBUTIONS

PWC PM10 PM2.5

Ca dust * 1.6 .47

Fe (inc re-*Suspension) 1.59 .63

Sea salt * 2.46 .66

SOA (HARMModel) .87 .65

Water 1.36 1.36_____________________________

Total 7.9 3.8

* based on maps from AEA (JS)

Total PM10 in 2010 Total PM2.5 in 2010

Source Apportionment PM10 in 2010 (UEP32 scenario)NB popn. weighted 1x1 km background concentrations

Source ApportionmentScenario UEP32

PM10 (2010)

PM10 (2020) NO2 (2020)

Local road

0ther roads

Non-road primary

Euro SIA

UK SIA

Ship PM

Import PM

Other

30.1 mg/m3 23.4mg/m3

22.3 mg/m3 18.9 mg/m3

M. Road M. Road

Southampton Southampton

2010 ROADSIDE SITES 2020

Roads “at risk” of exceedingAQ limit value (ann. ave. PM10 > 31.5 mg/m3)

km UK London

2010 157 34

2020 14 2

NB background higher over east UK (high Ca dust) -> exceedance outside London

Some comments

Modelled primary PM reduces with exhaust fraction becoming negligible, and road transport small (tyres and brakes) but are there sources missing from inventory?

SIA- also reduces with up to half imported from Europe and dependent on other countries reductions but uncertainties

Other components SOA, dust etc add up to as much or more than primary and SIA for PM10, and are also a significant addition to PM2.5-> more work needed on these.

In future: Move towards a speciated PM inventory re toxic components, black C etc