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SUMMARY:Molecular composition of biogenic secondary organic aerosols using
  ultrahigh resolution mass spectrometry: linking laboratory and field stud
 ies - Dr Ivan Kourtchev (University of Cambridge)
DTSTART:20130520T131500Z
DTEND:20130520T143000Z
UID:TALK41907@talks.cam.ac.uk
CONTACT:Dr Amanda Maycock
DESCRIPTION:Biogenic volatile organic compounds (BVOCs) play an important 
 role in atmospheric chemistry and give rise to secondary organic aerosols 
 (SOA)\, which have effects on climate and human health.  Laboratory chambe
 r experiments have been performed during several decades in an attempt to 
 mimic atmospheric SOA formation. However\, it is still unclear how close t
 he aerosol particles generated in laboratory experiments resemble atmosphe
 ric SOA with respect to their detailed chemical composition. To date\, mos
 t laboratory experiments have been performed using a single organic precur
 sor (e.g.\, alpha- or beta-pinene\, isoprene) while in the atmosphere a wi
 de range of precursors contribute to SOA\, which results most likely in a 
 more complex SOA composition compared to the one-precursor laboratory syst
 ems.\nThe objective of this work is to compare laboratory generated SOA fr
 om oxidation of BVOCs mixtures and remote ambient samples using ultrahigh-
 resolution mass spectrometry (UHR-MS) that allows detection of hundreds of
  individual SOA constituents. We examined aerosol samples from a boreal fo
 rest site\, Hyytiälä\, Finland and determined that a dominant fraction o
 f the detected compounds are reaction products of a multi-component mixtur
 e of BVOCs. In the subsequent smog chamber experiments\, SOA was generated
  from the ozonolysis and OH initiated reactions with BVOC mixtures contain
 ing species (alpha- and beta-pinene\, delta-3-carene\, and isoprene) that 
 are most abundant in Hyytiälä's environment. The laboratory experiments 
 were performed at conditions (e.g.\, RH\, aerosol seed\, and VOC ratios) t
 hat would resemble those at the boreal sampling site during the summer per
 iod. The elemental composition of the complex mixtures from laboratory gen
 erated SOA samples were compared with field samples using statistical data
  analysis methods.
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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