SOURCE APPORTIONMENT of
PARTICULATE MATTER
Imperial College
23rd April 2010
APRIL:Air Pollution Research in London
Where from?
nearest road
other UK sources
outside UK?
Which
Sources?
Emissions?
Concentration
Exposure
What chemical
composition?
SO4,NO3,NH4, C, Fe
etc
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
Road-side increment NOx,
primary PM
Open roads
rural
BRUTAL (UKIAM)-> modelling of
urban air quality
shallow
canyons
suburbs
Emissions each UK road link
NOx,PM,CO2,N2O (iMOVE)
Superimpose on background
concentration NOx, primary PM
from UK sources
PPM model
deep street
canyons dense
pop. city centre
Traffic flow, ave speed, vehicle mix+
data base emission factors
Grid 1x1 km emissions road
transport
Other UK emissions
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.
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
EU 27 (inc UK)
1964
71.7
96.3
57.9
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
Domestic
Industry
Roads
Off-road
Agri/nat.
3.0
9.9
24.6
20.1
7.4
6.7
Total UK
71.7
PRECURSOR EMISSIONS Secondary Inorganic Aerosol
kt
2010
2020
UEP32 scenario SO2
NOx
SO2
NOx
Power
138
296
71
144
Domestic
16
93
9
67
Industry
181
229
167
223
Roads
0.6
339
0.6
124
Off-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
CONCENTRATIONS OF SIA= SO4+NO3+NH4
FRAME and
UKIAM : use of pre-calculated
EMEP modelssource-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.
SIA components in 2020; based on FRAME/EMEP models
Frame NH4
PWM 0.74 mg/m3
SO4
0.82
NO3
fine 1.46
all 1.71
total
3.0 (PM2.5)
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 (HARM
Model)
.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 Apportionment
Scenario UEP32
PM10 (2010)
PM10 (2020)
NO2 (2020)
2010
ROADSIDE SITES
2020
Local road
0ther roads
Non-road
primary
Euro SIA
M. Road
30.1 mg/m3
UK SIA
M. Road
23.4mg/m3
Ship PM
Import PM
Other
Southampton
22.3 mg/m3
Southampton
18.9 mg/m3
Roads “at risk” of exceeding
AQ 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