Investigation of primary and secondary aerosols Investigation of primary and secondary aerosols from wood combustion with a high resolution from wood combustion with a high resolution
time of flight aerosol mass spectrometertime of flight aerosol mass spectrometer
Maarten Heringa Maarten Heringa
Laboratory of Atmospheric ChemistryPaul Scherrer Institut, Switzerland
Gothenburg 23-06-2008
Why are we interested in wood burning?Why are we interested in wood burning?
Biomass has the potential to become the world’s largest and most sustainable renewable energy source. (2004 Survey of Energy Resources World Energy Council)
Three billion people use small-scale wood fueled appliances that are both inefficient and highly polluting. (2007 Survey of Energy Resources World Energy Council)
Examples of wood burningExamples of wood burning
Wood burning in Roveredo SwitzerlandWood burning in Roveredo Switzerland
Wood is used as fuel for 75% of the domestic heating installationsin Roveredo Switzerland1
1(Alfarra et al., 2007 Environ. Sci. Technol)
Incomplete combustionC,H,O + O2 + → CO2 + H2O + CO + CxHyOz
N2 + impurities NOx + salts + minerals + BC
Complete combustionC,H,O + O2 + → CO2 + H2ON2 + impurities NOx + salts + minerals
Wood combustionWood combustion
Cellulose, hemicellulose and lignin are the main constituents of wood
Wood combustion markersWood combustion markers
Levoglucosan has been reported as major constituentof fine particulate emissions2 and its prominent fragmentat m/z 60 has been used as marker ion3
2(Reid et al., 2005 Atmos. Chem. Phys) 3(Alfarra et al., 2007 Environ. Sci. Technol)
Fragment m/z 60 is not unique for levoglucosan!
ObjectivesObjectives
• Characterization of primary emissions– Log wood burners– Automatic pellet burners– Wood burning markers m/z 60, 73 and 137
• Investigation of the stability of wood burning markers m/z 60, 73 and 137
• Investigation of the SOA formation potential of wood burning emissions in the PSI smog chamber
HR-ToF-AMS
Particle Inlet (1 atm)
QuadrupoleMass Spectrometer
Aerodynamic
Lens (2 Torr)
Chopper (150 Hz)
Turbo Pump (~1E-3 Torr)
TOF Region
AERODYNAMIC SIZING CHAMBER
Turbo Pump (~1E-5 Torr)
Turbo Pump (~1E-8 Torr)
Flow ~ 2.2 cm3/sec
Detector
Q-AMSQ-AMS
TOF Spectrometer
Flow ~ 1.3 cm3/sec
(Jayne et al., 2000; De Carlo et al., 2006)
Thermal Vaporization
(600°C)and
Electron Ionization
(70 eV)
eˉ
Critical orifice (130 µm)
Critical orifice (100 µm)
DETECTION CHAMBER
Primary emissionsPrimary emissions
Pellet burner80% (7.2 kW), 1.46 kg/h
Log wood burner0.5kg softwood + 2 x 2.7kg beech
Clean air generator
Heated Diluter(150°C)
Scheme of the setupScheme of the setup
TOF-AMS
Excess airExcess air
Diluter
MAAP
CO, CO2 ,O2 analyzer
FMPS
CVS
Dilution ratio~150x
Dilution ratio calculationsDilution ratio calculations
Pellet burnerPellet burner
140
120
100
80
60
40
20
0
Mas
s C
once
ntra
tion
(mg
m-3
)
15:1522.10.2007
15:30 15:45 16:00
Date and Time
Org NO3 SO4 Chl PAH
12
8
4
0
Ma
ss C
on
cen
tra
tion
(m
g m
-3)
15:3022.10.2007
15:40 15:50
Date and Time
10x
Start automatic burnerStart automatic burner
40
30
20
10
0
Nitr
ate
Eq
uiv
ale
nt
Ma
ss C
on
cen
tra
tion
(µ
g m
-3)
14012010080604020
m/z
60
73 137
10
8
6
4
2
0
Nitr
ate
Eq
uiv
ale
nt
Ma
ss C
on
cen
tra
tion
(µ
g m
-3)
14012010080604020
m/z
Species
AirWaterAmmoniumNitrateSulphateChloridePAHOrganics
Start peak
Wood burning markersm/z 60, 73, 137
10
8
6
4
2
0
Nitr
ate
Eq
uiv
ale
nt
Ma
ss C
on
cen
tra
tion
(µ
g m
-3)
14012010080604020
m/z
Species
AirWaterAmmoniumNitrateSulphateChloridePAHOrganics
Stable burning automatic burnerStable burning automatic burner
40
30
20
10
0
Nitr
ate
Eq
uiv
ale
nt
Ma
ss C
on
cen
tra
tion
(µ
g m
-3)
14012010080604020
m/z
60
73 137
Stable burning
Wood burning markersm/z 60, 73, 137
m/z 44 is the base peak(like in OOA)
(Lanz et al., 2008 Environ. Sci. Technol.)
Reproducibility of a log wood burnerReproducibility of a log wood burner
2.7kg of beech cut to a standard size and weight
(Weimer et al., 2008 Geophysical Research)
400
300
200
100
0
Ma
ss C
on
cen
tra
tion
(m
g m
-3)
14:0024.10.2007
15:00 16:00 17:00
Date and Time
Organics Ammonium Nitrate Sulphate Chloride PAH
Log wood burnerLog wood burner
1st load
2nd load
Start
Flaming
First load of beechFirst load of beech
60
40
20
0
Nitr
ate
Eq
uiva
lent
Mas
s C
onc
ent
ratio
n (
µg
m-3
)
14012010080604020
m/z
Species
AirWaterAmmoniumNitrateSulphateChloridePAHOrganics
60
13773
End of the fireEnd of the fire
8
6
4
2
0
Nitr
ate
Eq
uiva
lent
Mas
s C
onc
ent
ratio
n (
µg
m-3
)
14012010080604020
m/z
Species
AirWaterAmmoniumNitrateSulphateChloridePAHOrganics
60 137
73
Clean air generator
Heated Diluter
Excess air
Heated line (150°C)
1:8
~4 L/min
Smog chamber setupSmog chamber setup
Aethalometer
CO,CO2,NOx,O3
TOF-AMSCPC + SMPS
CO2
Smog chamber experimentSmog chamber experiment
• Humidification of the chamber• Background measurements• Start the burner• Filling the chamber• Measurement
primary emissions• Lights on
Organics and black carbonOrganics and black carbon
120
100
80
60
40
20
0
µg/
m3
543210-1
Time after lights on (h)
2.0
1.5
1.0
0.5
0.0
Org
/BC
Org BC Org/BC
Wood burning markersWood burning markers
120
100
80
60
40
20
0
Org
µg/
m3
543210
Time after lights on (h)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Perce
nta
ge m
/z 60
3.0
2.5
2.0
1.5
1.0
0.5
0.0
M/z
60
µg/
m3
org ratio_60_org org60
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
Org
44/
org
543210
Time after lights on (h)
org44_to_org start org44_to_org flaming
100
80
60
40
20
0
60.460.260.059.859.6m/z
2.0
1.5
1.0
0.5
0.0
Nitr
ate
eq
uiv
ale
nt
ma
ss (
µg
m-3
)
OxidationOxidation
50
40
30
20
10
0
60.460.260.059.859.6m/z
1.0
0.8
0.6
0.4
0.2
0.0
Nitr
ate
eq
uiv
ale
nt
ma
ss (
µg
m-3
)
100
80
60
40
20
0
44.444.244.043.843.6m/z
2.0
1.5
1.0
0.5
0.0
Nitr
ate
eq
uiv
ale
nt
ma
ss (
µg
m-3
) CO2+
C2H4O+
500
400
300
200
100
0
44.444.244.043.843.6m/z
10
8
6
4
2
0
Nitr
ate
eq
uiv
ale
nt
ma
ss (
µg
m-3
)
ConclusionsConclusions
Automatic pellet burners produce high concentrations of organics during the ignition
During stable burning the spectrum of the organics is dominated by m/z 44 which is the dominant signal of OOA
Log wood burners show large variations in concentration between runs and during a burning cycle
The wood burning marker at m/z 60 is mainly formed during the start consist of one molecular formula is stable for > 5 hours
Oxidation of the gas phase emissions of the tested log wood burner increased the organic aerosol mass with a factor of ~ 2-3
Take homeTake home
Burning automatic pellet burners emit less organics during stable burning than log wood burners. Nevertheless, high concentrations of organics are emitted during the ignition.
Log wood burners show large variations in emissions between runs and during a single burning cycle. The spectral changes during the burning cycle makes it more difficult to identify a representative source profile.
A particle filter can reduce the primary aerosol emissions. However, due to SOA formation, only a reduction of 25-40% can be established (for a particle filter with 80% efficiency)
Thanks to…Thanks to…
Thank you for your attention
Roberto Chirico, Peter DeCarlo, Agnes Richard, Torsten Tritscher, Marco Steiger, Rami Alfarra,
Andre Prévôt & Urs Baltensperger
Michael Sattler & Christian Gaegauf
Nickolas Meyer & Heinz Burtcher