Organic aerosols in relation to small- scale wood combustion, forest fires and traffic
R. Hillamo, S. Saarikoski, H. Timonen, K. Saarnio, A.
Frey, M. Aurela
Finnish Meteorological Institute, Helsinki, Finland
L. Järvi, M. Kulmala
University of Helsinki, Helsinki, Finland
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 2
Measurements
Site
• SMEAR III (60°20'N, 24°97’E), urban background
• Local sources: traffic, biomass combustion
• Long-range transport ~50% of PM2.5, frequent wild fire plumes
Period shown here
• June 2006–February 2007
SMEAR III belongs to the European ACCENT network – access to field and laboratory infrastructures
Helsinki
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 3
Identification of sources –different approaches
Time resolution 24-48 h
• Needs long-term measurements + large sets of chemical components → seasonal (annual) cycles
Time resolution < 3 h (for several components)
• Diurnal variations, good timing for specific episodes (pollution or clean)
• Excellent data for modellers,epidemiological studies and for statistical methods (e.g. PMF)
Same observations at several sites
• Helsinki (urban)
• Hyytiälä (rural forest)
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 4
Methods
Sampling (24 h)
• PM 1 filter sampling (80 lpm, 47 mm filter)
• Analytical techniques: IC, TOC, LC/MS, TOT (Sunset lab) Online/real-time (1 s – 3 h)
• PILS-IC for ions (15 min)
• PILS-Total organic carbon analyzer for WSOC (5 min)
• Semicontinuous EC/OC (Sunset Lab, 1-3 h)
• Aethalometer (black carbon, 5 min)
• PSAP (aerosol absorption, 1 s)
• Twin-TEOM (PM 1 , PM 1-10 , 30 min)
• DMPS, APS (particle number size distribution, 10 min)
• O 3 , NOx, CO
• Meteorology
Site comparison (Helsinki/urban – Hyytiälä/rural, distance 200 km)
Black carbon (soot) data from Helsinki 1996-2005
Virkkula et al. (2007) A Simple Procedure for Correcting Loading Effects of Aethalometer Data, J. Air & Waste Manage. Assoc.
57:1214–1222
• Correction of BC data (Virkkula et al., 2007)
• Selection of periods to be
compared (1996-1997, 2000-
2001, 2004-2005)
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 6
Black carbon (PM 2.5 ) in Helsinki 1996-2005:
concentrations (μg/m 3 ) during comparable periods
Järvi et al. (2007) Atmos. Chem. Phys. Discuss., 7, 14265–14294
Traffic intensity vs. BC concentrations
Järvi et al. (2007) Atmos. Chem. Phys. Discuss., 7, 14265–14294
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 8
PM 2.5 from wood combustion and wild fires
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
6.2.06 13.2.06 20.2.06 27.2.06 6.3.06 13.3.06 20.3.06 27.3.06 3.4.06 10.4.06 17.4.06 24.4.06 1.5.06 8.5.06 15.5.06 22.5.06 29.5.06 5.6.06 12.6.06 19.6.06 26.6.06 3.7.06 10.7.06 17.7.06 24.7.06 31.7.06 7.8.06 14.8.06 21.8.06 28.8.06 4.9.06 11.9.06 18.9.06 25.9.06 2.10.06 9.10.06 16.10.06 23.10.06 30.10.06 6.11.06 13.11.06 20.11.06 27.11.06 4.12.06 11.12.06 18.12.06 25.12.06 1.1.07 8.1.07 15.1.07 22.1.07 29.1.07 5.2.07 12.2.07 19.2.07 26.2.07
Da te
levoglucosan µg/m3
0 2 4 6 8 10 12 14 16 18
OC µg/m3
MA OC 0.0
0.1 0.2 0.3 0.4 0.5 0.6 0.7
6.2.06 13.2.06 20.2.06 27.2.06 6.3.06 13.3.06 20.3.06 27.3.06 3.4.06 10.4.06 17.4.06 24.4.06 1.5.06 8.5.06 15.5.06 22.5.06 29.5.06 5.6.06 12.6.06 19.6.06 26.6.06 3.7.06 10.7.06 17.7.06 24.7.06 31.7.06 7.8.06 14.8.06 21.8.06 28.8.06 4.9.06 11.9.06 18.9.06 25.9.06 2.10.06 9.10.06 16.10.06 23.10.06 30.10.06 6.11.06 13.11.06 20.11.06 27.11.06 4.12.06 11.12.06 18.12.06 25.12.06 1.1.07 8.1.07 15.1.07 22.1.07 29.1.07 5.2.07 12.2.07 19.2.07 26.2.07
Da te
levoglucosan µg/m3
0 10 20 30 40 50 60
PM2.5 µg/m3
MA PM2.5
MA= monosaccharide anhydrates= sum (levoglucosan+mannosan+galactosan)
Wood combustion
Online measurements of PM 1 chemistry
- time resolution 15 min-3h - 9 months campaign
NO, NO2 ppb 0 50 100 150 200
CO ppm
0 200 400 600 800 1000 1200 1400 NO
CO NO2
Saturday 10 Feb
Local time
03 06 09 12 15 18 21 03 06 09 12 15 18 21
00 00 00
OC, EC µg m-3
0 2 4 6 8 10 12 14
K µg m-3
0.0 0.3 0.6 0.9 1.2 1.5
OC EC K
µg m-3
0 1 2 3 4 5 6
SO4 NH4 NO3
µg m-3
0.0 0.2 0.4 0.6 0.8 1.0
Cl Na
Local time
03 06 09 12 15 18 21 03 06 09 12 15 18 21
00 00 00
Temperature °C
-20 -15 -10 -5 0
wind speed m s-1
0 1 2 3 4 5
T wind speed
Sunday 11 Feb a)
b)
c)
d)
e)
Saarikoski S. et al., 2008, Atmospheric
Chemistry and Physics, submitted
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 10
Wild fire spring 2006: mass closure study
a) Mass closure
µg/ m
30 10 20 30 40 50 60
Elemental carbon Mass PM
2.5Organic compounds Ions
Sulfate
EC PM
2.5POM Other ions SO
4b) Carbonaceous
26 .3 . 28 .3 .
30.3. 1.4. 3.4. 5.4 . 7.4 .
9.4. 11.4. 13.4. 15 .4.
17 .4.
19 .4.
21 .4.
23.4. 25 .4.
27 .4.
29 .4. 1.5. 3.5. 5.5. 7.5.
9.5 .
µg/ m
30 5 10 15 20
Elemental carbon
Water-insoluble organic carbon Water-soluble organic carbon
Saarikoski et al. (2007). Chemical composition of aerosols during a major biomass burning episode over
northern Europe in spring 2006: Experimental and modelling assessments. Atmos. Environ. 41:3577-3589 .
Episode in spring 2006. Episode in August 2006.
From filter sampling
Date 15-Apr 22-Apr 29-Apr 06-May 13-May
mass concent rat ion, µg m
-30 10 20 30 40 50
60 Spring 2006
01-Aug 08-Aug 15-Aug 22-Aug 29-Aug
mass concent rat ion, µg m
-30 10 20 30 40 50 60 EC
WISPOM WSPOM Other ions Sulphate PM
2.5August 2006
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 12
August episode with 3-hour time-resolution
From on-line measurements
August 2006
Date
08-Aug 12-Aug 16-Aug 20-Aug 24-Aug
mas s c onc entrati on, µg m -3
0 20 40 60 80 100
EC
POM
Other ions
Sulphate
PM 2.5
Wildfire: August 15, 2006
D a [µm]
0.01 0.1 1 10
dm/dlogD a [µg/m 3 ]
0 20 40 60 80 100 120
A: 00-03 B: 03-06 C: 06-09 D: 09-12 E: 12-15 F: 15-18
A B
C D
E F
*
A: 0 0- 03
B: 0 3-0 6
C: 0 6- 09
D: 0 9-1 2
E: 1 2-1 5
F: 1 5- 18
mass co ncen tra tion , µg m
-30 10 20 30 40 50 60
*) POM and EC not available
other ions Ammonium Sulphate POM EC
PM
2.5mass
3-hour mass size distributions (A-F) during the progress of the plume on August 15, 2006.
(F represents a non-plume situation.)
The PM 2.5 mass and chemical composition of PM 1 on August 15, 2006 with 3-hour time-
resolution.
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 14
Biomass burning tracers
K/Levoglucosan K/Oxalate Oxalate/Levoglucosan
Spring episode 1.04 0.85 1.28
August episode 1.02 0.31 5.13
Plumes of August episode
0.32 0.32 1.03
”Non-plume”-samples 1.71 0.29 9.22
• Spring episode: April 24 – May 7, 2006
• August episode: August 1 – August 28, 2006
• Plume samples have been chosen according to the high content of levoglucosan
Spring flaming, August plumes smoldering fires
Levoglucosan/potassium ratio
Ja n
Feb Ma r
Ap r
Ma y
Jun Jul
Aug
Se p
Oc t
No v
Dec Jan
le vo gl uc os an/ pot as si um r at io
0 1 2 3 4
Levoglucosan better qualitative tracer than K +
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 16
Long-term measurements: two sites
• PM 1 filter sampling (Feb 07-Feb 08)
Organic carbon
µg /m
30 1 2 3 4 5 6 7
Hyytiälä Helsinki
Elemental carbon
Mar-2007 Apr-2007 May-2007 Jun-2007 Jul-2007 Aug-2007
µg/m
30
1
2
3
Levoglucosan
Temperature °C
-30 -20 -10 0 10 20 30
Levoglucosan/POM
0.0001 0.001 0.01 0.1
Oxalate
Temperature °C
-30 -20 -10 0 10 20 30
Oxalate/POM
0.0001 0.001 0.01 0.1
OC
Temperature °C
-30 -20 -10 0 10 20 30
C oncen tration µg /m
30.01 0.1 1 10 100
Summer Fall Winter
Biomass burning Episode
Contribution of POM to PM 2.5
Temperature °C
-30 -20 -10 0 10 20 30
Co ntribu tion to PM
2.50.01 0.1 1 10
Summer Fall Winter
Biomass burning Episode
Seasonal variation in Helsinki:
Organic carbon
Biomass burning
episode
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 18
PM 1 organic carbon in Helsinki
Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
C ontribution to OC
0.0 0.2 0.4 0.6 0.8 1.0
Traffic
Biomass Combustion Unknown
Fe b Ma r
Ap r Ma y
Ju n Ju l Au g
Sep Oc t No v
De c Ja n
Fe b
contribution t o OC
0.00 0.01 0.02 0.03 0.04
Oxalate
-Traffic (primary) based on EC/OC ratio
-Biomass combustion based
on levoglucosan to OC ratio
- Unknown is obviously SOA
Sources of PM 1 (PMF)
Factor 2
OC EC WSOC levog NH4 K SO4 Ox O3 NO NO2
relative contribution
0.0 0.2 0.4 0.6 0.8 1.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
relative contribution
0 2 4 6 8 10
Factor 3
OC EC WSOC levog NH4 K SO4 Ox O3 NO NO2
relative contribution
0.0 0.2 0.4 0.6 0.8 1.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
relative contribution
0 1 2 3 4 5
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
relative contribution
0 1 2 3 4
Factor 4
OC EC WSOC levog NH4 K SO4 Ox O3 NO NO2
relative contribution
0.0 0.2 0.4 0.6 0.8 1.0
Factor 1
OC EC WSOC levog NH4 K SO4 Ox O3 NO NO2
relative contribution
0.0 0.2 0.4 0.6 0.8 1.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
relative contribution
0 1 2 3 4 5
SOA
Biomass combustion
LRT
Traffic
Saarikoski S. et al., 2008, Atmospheric
Chemistry and Physics, submitted
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 20
Concentrations from different sources
b) Water-soluble organic carbon
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
co nc en tr at ion µ g m
-30 1 2 3 4
a) Organic carbon
co ncentrati on µg m
-30 1 2 3 4 5 6 7
Traffic SOA
Biomass combustion Long-range transport
• PM 1 (<1µm)
• 24 h sampling,
chemical analysis
in laboratory
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 21
Seasonal source contributions in Helsinki
The source contributions for OC and WSOC in winter (Dec–Feb), spring (Mar–May), summer (Jun–Aug) and fall (Sep–Nov) (average ±SD). Sources and their contributions were identified by PMF.
Winter Spring Summer Fall
% of OC Secondary organic
aerosol 16 ± 11 34 ± 17 64 ± 12 32 ± 18
Biomass combustion 41 ± 15 12 ± 8.9 3.4 ± 6.0 20 ± 14 Long-range transport 17 ± 13 29 ± 10 19 ± 11 21 ± 14
Traffic 26 ± 12 25 ± 13 15 ± 13 27 ± 15
% of WSOC
Secondary organic
aerosol 28 ± 18 49 ± 19 78 ± 8.8 47 ± 21
Biomass combustion 38 ± 16 11 ± 8.1 2.3 ± 4.1 18 ± 15 Long-range transport 18 ± 14 27 ± 11 13 ± 8.4 20 ± 13
Traffic 16 ± 8.5 14 ± 9.0 6.6 ± 6.7 15 ± 11
Saarikoski S. et al., 2008, Atmospheric Chemistry and Physics, submitted
March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 22
24-hour sample
24-hour PM
1filter sample
22/08 09:00 Date 23/08 09:00
mass concen tr a tion, µg/m
30 10 20 30 40
PM1-2.5 Potassium Ammonium Nitrate Sulphate Oxalate WSPOM WISPOM EC
24-hour PM
2.5sample
22/08 09:00 Date 23/08 09:00
ma ss co ncen tr atio n, µg /m 3
0 10 20 30 40
PM
2.5On-line measurement
On-line measurements
Date
22/08 09:00 22/08 15:00 22/08 21:00 23/08 03:00 23/08 09:00
m as s c on cent ra tion , µ g /m
30 10 20 30 40
PM1-2.5 Potassium Ammonium Sodium Chloride Nitrate Sulphate Oxalate POM EC
On-line PM
2.522/08 09:00 22/08 15:00 22/08 21:00 23/08 03:00 23/08 09:00 Date
mass con ce nt rat ion, µg /m
30 10 20 30 40
PM
2.5March 19, 2008
R. Hillamo, Cost 633, Brussels, March 13, 2007 24