chemical speciation of pm and mass closure
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Chemical speciation of PM and mass closure. David Green, Gary Fuller & Anja Tremper King’s College London. Contents. London sampling campaigns Methodology Use of uncertainty Results Source apportionment – London and Paris. Sampling campaigns. Summer campaign Aug-Oct 2008 - PowerPoint PPT PresentationTRANSCRIPT
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Chemical speciation of PM and mass closure
David Green, Gary Fuller & Anja Tremper
King’s College London
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ContentsLondon sampling campaigns
Methodology
Use of uncertainty
Results
Source apportionment – London and Paris
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Sampling campaignsSummer campaign
• Aug-Oct 2008• Brent & Tower Hamlets
Winter 2008 campaign• Nov-Dec 2008• Camden, Brent & Tower
Hamlets
Further Camden campaigns
• May - June 2010• PM10 and PM2.5
• Summer 2010• Further PM10• Construction and another
roadside
Brent - Ikea
Tower Hamlets – Blackwall Tunnel
Camden – Swiss Cottage
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Methodology
Pragmatic mass closure
2 Partisols• 1 Teflon – Mass, IC, ICP-MS• 1 Quartz – EC/OC
ERG mass closure
Existing TfL monitoring sites• TEOM / FDMS• Aethalometer (EC)
Sampled onto alternate filters on different days
• Mixed cellulose esters – ICP-MS• Quartz – EC/OC• Longer time period• Used one sampler
Existing Defra monitoring at North Ken and Marylebone Road for concentrations of regional pollutants when not measured directly
• IC and EC/OC• Nitrates, Sulphates, Chlorides, SOA
Aethalometer measurements for EC and POA using site specific empirical relationships
Results in time series composed of two datasets
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Methodology
MassFDMS – direct massTEOM – used Volatile Correction Model (VCM)
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Methodology Elemental CarbonDataset A
• Aethalometer using Xgenline empirical relationship
• Uncertainty included
Dataset B• Sunset
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Methodology Primary Organic CarbonEC tracer measurement used to split SOA and POA
• Evidence of organic gas adsorption onto filters
• Intercept and slope derived using min 5% of EC/OC ratios
Factor for organic mass of 1.4 used (Japar, 1984) from direct measurements of diesel emissions
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Methodology Secondary Organic CarbonEC tracer measurement used to split SOA and POA
• SOA = OC - (EC/OC)prim x EC• Evidence of organic gas adsorption onto
filters• Intercept and slope derived using min 5% of
EC/OC ratios• Factor for organic mass of 2.1 used (Turpin
and Lim, 2001), recommended for non-urban aerosol
Good agreement between sites• Dataset A mean of available measurements
in London direct• Dataset B Sunset analysis• Variation included in uncertainty calculation
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Methodology Nitrates, sulphates & chloridesMeasurements from mean of Marylebone and North Kensington usedFactors applied to account for cationsNitrate can be ammonium or sodium
• Masses similar (18 or 23)• Harrison (2003) found 60% NH4NO3
• Applied a factor of 1.32 (60% NH4NO3 and 40% NaNO3)
Sulphate• Applied factor of 1.19
Chloride• Applied factor of 1.65
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Methodology WaterUsed Aerosol Inorganic Model (AIM)
• Used nitrate and sulphate measurements as inputs
• Used FDMS sampling conditions of 30% RH and 30ºC
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Methodology Iron Rich DustSplit into Minerals, Iron Oxide and MetalsMeasured wide range of metals (Fe, Ca, Al, Ba, Cu, Mo, Mn, Ni, Pb, Sb, Sr, V and Zn)Used Al as a tracer for feldspars (e.g. KAlSi3O8)
• Applied factor of 8.4• Included uncertainty in this factor
Ca used as a tracer for calcite and gypsum
• Applied factor of 3.8• Included uncertainty in this factor
These grouped together as mineralsFe used as a tracer for an iron oxide (FeO, Fe2O3 or Fe3O4)
• Applied factor of 1.37• Included uncertainty in this factor
Other metals included as ‘raw’ massOn days when ICP-MS not undertaken (dataset B) difference between PM10 mass and available components used to assess this
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Alternate filters
Component Dataset A Dataset B
EC Aethalometer
Sunset
POA Aethalometer
Sunset
SOA Regional Sunset
Nitrates Regional IC
Sulphates Regional IC
Chlorides Regional IC
Water AIM AIMMinerals / unidentified
ICP-MS Difference
A
B
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Site Variability
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Daily Variability
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Uncertainty analysis
Guide to uncertainty in measurement methodology (GUM)
Simple…
Measurement equation• TEOMVCM = TEOM – (ƒVCM x FDMS purge) – FDMS purge
Uncertainty equation• UVCM = 2 x √(uTEOM)2 + (uƒVCM x FDMS purge)2 + (ƒVCM x uFDMS purge)2
Complex…
Total Mass• uTotalMassA = 2x √(uECa
2 + uPOAMa2 + uSOAMregional
2 + uNO3total2 + uSO4total2 + uCltotal
2 + uWater2 + uMinerals2 + uIronOxide2 + uMetals2)
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Validation against PM10Tower Hamlets
4Brent 4Camden 1
y = 0.91 (±0.05) x+ 2.19 (±1.91)
r2 =0.84
y = 1.11 (±0.07) x+ -3.88 (±2.26)
r2 =0.82
y = 0.87 (±0.11) x+ 6.9 (±3.22)
r2 =0.58
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Analysis outputs - Comparison to source apportionment
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Dataset Date
PM10
(µg
m-3)
EC (µ
g m
-3)
POA
M (µ
g m
-3)
SOA
M (µ
g m
-3)
Nitr
ate
(µg
m-3
)
Sulp
hate
(µg
m-3
)
Chl
orid
e (µ
g m
-3)
Wat
er (µ
g m
-3)
Min
eral
s (µ
g m
-3)
Iron
Oxi
de (µ
g m
-3)
Oth
er m
etal
s (µ
g m
-3)
Uni
dent
ified
(µg
m-3
)
Tota
l (µg
m-3)
Epis
ode
driv
er(s
)
Bre
nt
Dat
aset
A
04/11/08 56.3 12.3 3.9 5.5 16.7 11.6 5.4 0.0 7.3 2.6 0.3 -9.4 65.7 S
20/09/08 52.0 13.6 4.3 3.8 9.0 3.0 2.5 2.0 9.9 3.7 0.4 -0.3 52.3 PSM
26/09/08 51.0 12.3 3.9 5.9 9.7 5.5 4.3 1.4 9.1 3.5 0.4 -4.9 55.9 SM
16/12/08 50.1 10.1 3.2 6.0 5.0 2.3 1.7 1.0 2.2 2.4 0.2 16.0 34.1 N
Mean 29.4 6.7 2.1 3.2 4.2 2.4 3.4 0.7 3.9 1.9 0.2 0.7 28.7
Bre
nt
Dat
aset
B
30/08/08 57.5 6.0 1.9 6.5 18.8 8.2 3.1 3.9 - - - 9.1 48.4 S
17/09/08 53.3 11.2 3.5 3.4 9.0 2.9 3.1 2.0 - - - 18.1 35.1 M
27/09/08 58.7 10.1 3.2 8.3 16.2 6.0 1.8 3.5 - - - 9.5 49.1 S
07/12/08 56.8 14.2 4.5 10.0 12.0 2.0 4.9 3.1 - - - 6.1 50.7 PS
Mean 28.1 6.7 2.1 3.0 4.5 2.3 3.5 0.9 - - - 5.1 23.0
Tow
er H
amle
ts
Dat
aset
A
31/08/08 61.5 6.1 4.6 7.1 26.6 6.5 4.7 6.5 2.3 1.6 0.2 -4.7 66.2 S
22/09/08 65.4 8.2 6.2 2.7 5.3 2.3 3.0 1.1 12.2 3.3 0.4 20.6 44.8 N
04/11/08 57.1 4.6 3.5 5.5 16.7 11.6 5.4 0.0 9.2 1.7 0.4 -1.5 58.6 S
06/11/08 69.5 9.7 7.3 7.9 6.2 5.2 1.0 0.0 18.8 4.0 0.6 8.8 60.7 SM
10/12/08 64.6 6.9 5.2 6.5 5.7 1.1 4.0 1.5 18.7 4.4 0.4 10.2 54.3 M
16/12/08 58.6 8.5 6.5 6.0 5.0 2.3 1.7 1.0 9.9 3.5 0.4 13.8 44.8 N
Mean 33.1 5.2 3.9 3.4 4.4 2.2 3.5 0.8 6.5 2.3 0.3 0.7 32.5
Tow
er H
amle
ts
Dat
aset
B
30/08/08 54.0 1.8 1.3 7.3 18.8 8.2 3.1 3.9 - - - 9.5 54.0 S
19/09/08 53.7 6.9 5.2 6.6 6.8 2.8 3.6 1.4 - - - 20.3 53.7 N
05/11/08 69.2 7.9 6.0 9.3 5.5 5.8 0.7 0.0 - - - 34.1 69.2 SM
07/12/08 56.1 8.2 6.2 13.8 12.0 2.0 4.9 3.1 - - - 5.9 56.1 S
11/12/08 60.2 9.8 7.4 6.5 11.4 2.1 5.3 2.9 - - - 14.8 60.2 S
17/12/08 52.3 8.3 6.2 7.7 3.3 1.3 4.3 0.7 - - - 20.5 52.3 S
Mean 34.2 4.9 3.7 3.5 4.7 2.2 3.4 0.9 - - - 10.8 34.2
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Next steps and improvements…
Organic absorption onto quartz filters• Quartz back quartz study to assess adsorption in next 2 months
Efficiency of aqua regia digest for extracting Al• HF digest
ICP-MS for Ca and Al• Comparisons with ICP-AES
Al as a tracer for Si• XRF analysis
How representative is one location to another• More direct measurements
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Acknowledgements
London Borough of Camden
Transport for London
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Source apportionment of PM10 in London and Paris-intial results
Gary Fuller and Anna Font Font King’s College
LondonMarch 2010
Centre for Environment and Health
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Relationship between annual mean PM10 and NOX in London Fuller et al., (2002), Fuller and Green (2006)
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Relationship between annual mean PM10 and NOX in Paris
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Primary PM10 : NOX ratio London and ParisProgressive Euro classes preferentially abate PM10 over NOX then grad should
be decreasing!Effects of London specific PM measures?
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Non-primary PM10 London and ParisNon primary PM10 converging
Paris did not experience 2006 elevation seen in London