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

• 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.

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)

Performed laboratory studies and claimed that atmospheric oxidation of monoterpenes leads to aerosol formation

FromMonoterpenes

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 ofinterest

Problem lack of knowledge on Secondary Organic Aerosols:

Where do they come from? Isoprene?Monoterpenes?

How are they formed?Oxidation in the atmosphere

SOAOHVOC hv

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)?

Problem

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

3 extractions per filter

Solutions are reduced to 1 mL

sonicator

Addition of organic solvent

GCMS

Derivatize

Filtrate

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.