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Investigation of Secondary Organic Aerosol Formation in the New PSI Smog Chamber

English title Investigation of Secondary Organic Aerosol Formation in the New PSI Smog Chamber
Applicant Baltensperger Urs
Number 108095
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.04.2005 - 31.03.2008
Approved amount 283'197.00
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Keywords (11)

Aerosol; Atmospheric chemistry; Secondary organic aerosol; polymers chemical analysis; organic acids; health effects; SOA; smog chamber; air quality; oligomers; chemical analysis

Lay Summary (English)

Lay summary
Photo-oxidation experiments with various precursors representing anthropogenic and biogenic emissions are performed in the new PSI smog chamber to investigate the formation of secondary organic aerosol (SOA). The gas and aerosol phase are characterized with a broad variety of state of the art instrumentation. All precursors investigated so far (trimethylbenzene, alpha-pinene, isoprene) showed formation of oligomers, i.e., species with high molecular weight (up to about 800 Da). This process has important implications for the ambient atmosphere, as it substantially enhances the formation potential of SOA and thus the overall concentration of secondary organic aerosol in the atmosphere: small (highly volatile) molecules which otherwise would not partition to the aerosol may well do so through this oligomerization process. These oligomers, which so far have been identified off-line, were measured here for the first time also on-line. As a result of the oxidizing atmosphere the SOA is further oxidized continuously after formation, thus increasing the hygroscopicity of the particles and thus the ability to form cloud condensation nuclei with aging time.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
103605 EUROTRAC: Sources, formation and composition of particulate organic carbon in the lower troposphere 01.04.2004 Project funding (Div. I-III)
120156 Investigation of Secondary Organic Aerosol Formation in the PSI Smog Chamber 01.04.2008 Project funding (Div. I-III)
113067 W-ToF High Resolution Aerosol Mass Spectrometer 01.10.2006 R'EQUIP