On the Formation of Secondary Organic Aerosols and
the develpment of an Analytical Technique to
identify their tracers
Nélida Jocelyn González
Supervisors:
Barbara Nozière, Institute of Applied Environmental Science,SU
Anna Karin Borg-Karlsson, Department of Chemistry, KTH
Radovan Krejci, Department of Meteorology, SU
Introduction
• What? SOA
• Why?
Importance
• Environment
• Climate
• Health
• When? Sept 07- Sept 11
• Where?
▫ BOOAR (Biogenic organic aerosol over Amazonian Rainforest)
▫ EUSAAR (European Supersites Atmospheric Aerosol Research)
• How?
Outline
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Background
SOA of interest
Sites
Project questions
Objectives
Methodology
• Chemical analysis
• Ambient sampler
• Current state
Background
 Mid and late 1950s- Aerosol scientist focused on
pollution particles/ urban smogs
 1960- Biogenic hydrocarbon emissions were noted as
atmospheric aerosol- forming potential (Went, 1960;
Yu et al., 1999).
 1980- 1990s- Field measurements of gas phase
monoterpenes, yet very few studies regarding their
oxidation products (Roberts et al.,1983; Zimmerman et
al., 1988;Clement et al.,1990;Yu et al., 1999)
Beginning
of Biogenic
emissions
research
and SOA
Background
 1997- Hoffmann et al.
Performed laboratory studies and
claimed that atmospheric oxidation of
monoterpenes leads to aerosol
formation
 1999- Griffin et al.
 2000s- Isoprene has been considered as precursor for SOA
according to smog chamber studies
(Kroll et al, 2005;Kroll et al., 2006; Henze and Seinfeld, 2006)
From
Monoterpenes
Larsen, B.R., et al., 2000
From
Isoprene
Claeys, M., et al., 2004
Manaus Station
• Amazon Tropical Rainforest
• Largest production of SOA
globally
• largest impact on climate
• Region of very intensive
convection
• cloud formation and long-range
transport of mass and energy
Hyytiälä station
• Reported SOAs of
interest
Problem
 lack of knowledge on Secondary Organic Aerosols:
 Where do they come from?
 Isoprene?
 Monoterpenes?
 How are they formed?
 Oxidation in the
atmosphere
hv
VOC  OH  
SOA
Problem
 How can they be differentiated? (not really primary!?)
 2-methyl tetrols, pinanoaldehyde, pinic acid, Nor pinonic
acid?
 How are they distributed in the atmosphere?
 How to develop a SOA sampler/ (atmospheric ambient chamber)?
Photo: Leslie Taylor
Objectives
• To analyze atmospheric samples chemically clearly
distinguishing between primary and secondary.
• To determine the extraction and derivatization method that
yields secondary organic aerosols (tracers).
• Test different analytical techniques that will identify SOA
(considering atmospheric concentrations)
• GC-MS
• LC-MS
Methodology
• Generate standards
• Determine lowest Detection limit
• Separation monoterpenes and isoprene oxidation products
• Natural emission ratios of each compared to atmospheric ratios
• Collect samples from the three sites
• Extract
• Derivatize
Methodology
• Design and build sampling chamber
suitable for these purposes
• Determine a good separation
system that will prevent different
particles/ POAs from coming into
the chamber
• Considering an adequate
volumetric flow that will allow the
formation of SOA
• Test the well- functioning of the
chamber
• Sampling in Sweden/ Finland
Courtesy of Barbara Nozière, 2007
Methodology
▫ Sampling in the Amazonian
tropical rainforest.
▫ Application of analytical method for the
identification and quantification of SOA tracers
▫ Analyses of products
▫ Results
▫ Determine mechanisms based on the
on the results.
▫ Do they agree or not with smog
chamber experiments?
Current state
▫ Extraction
▫ LC-MS
▫ no detection/separation of standards
▫ GC-FID Analyses of products
 For 2-methylerythritol
 For 2-methylthreitol
▫ GC-MS: currently developing program method for the
identification
Addition of
organic solvent
sonicator
3 extractions per
filter
Solutions are
reduced to 1 mL
Filtrate
GCMS
Derivatize
Collaborations
• University of Sao Paulo
▫ Prof. Paulo Artaxo
 PhD Student Paulo Henrique, RIP
• University of Helsinki
▫ Dr. Pasi Aalto
▫ Dr. Janne Rinne
 Hyytiälä station- Dr. Janne Levula
• KTH
▫ Dr. Johan Pettersson Redeby
• Aspvreten
▫ Hans Karlsson
• Thanks for your attention!
List of References
 Andreae, M. O. and P. J. Crutzen, Atmospheric aerosols:
Biogeochemical sources and role in atmospheric chemistry, Science,
276, 1052-1055, 1997.
 Kavouras, I.G., Mihalopoulos, N. and E. Stephanou, Formation of
atmospheric particles from organic acids produced by forests,
Nature, 395, 683- 686.
 Stephanou, Euripides G., A forest air of chirality, Nature, 446, 991,
2007.
 Williams, J., N. Yassaa, S. Bartenbach, and J. Lelieveld, Mirror
image hydrocarbons from tropical and boreal forests, Atmospheric
chemistry and physics, 7, 973- 980, 2007.
 Yu, J., R.J. Griffin, D.R. Cocker III, R.C. Flagan, and J.H. Seinfeld,
Observation of gaseous and particulate products of monoterpene
oxidation in forest atmospheres, Geophysical Research Letters, 26,
1145- 1148, 1999.
Take home messages
• Smog chamber ≠
atmosphere
▫ Yet they have been helpful to study mechanisms
▫ Chamber studies are performed with controlled
conditions (precursor concentrations, oxidizings
agents, temperature, pressure– one single compound
with one selected reagent reactions) and the system is
discriminative of other simultaneous chemical
processes.
• Too many assumptions in the study of
atmospheric SOA due to results in smog
chamber results
▫ Due to the lack of evidence some few have
concluded that the unknowns in the atmosphere
are SOA as they cant determine they are POA
▫ This has been possible as chamber results suggest
such results however atmospheric environment
involves much more processes than those
performed in chamber experiments.