Download Abstracts Here - IGAC Project

List of Abstracts 146which compare favourably with current global estimates for SOA burdens.P-Transformation.44 ID:4218 10:30Identification of biogenic SOA based on NMR spectral signatures observed in chamber experimentsand at pristine forested environmentsEmanuela Finessi 1 , Stefano Decesari 1 , Thomas F. Mentel 2 , Urs Baltensperger 3 , Risto Hillamo 4 , MariaCristina Facchini 11 Institute of Atmospheric Sciences and Climate (ISAC-CNR), Italy2 Institut für Chemie und Dynamik der Geosphäre (ICG-2), Forschungzentrum Jülich, Germany3 Laboratory of Atmospheric Chemistry, Paul Scherrer Institut (PSI), Switzerland4 Finnish Metereological Institute (FMI), FinlandContact: e.finessi@isac.cnr.itDuring the last years major efforts have been made to understand secondary organic aerosol (SOA)formation by the oxidation of biogenic volatile organic compounds. Nevertheless current estimates of globalSOA production remain extremely uncertain due to the lack of observations capable to discern the biogenicSOA from other oxidized organic aerosol types. In the present study new results are shown on the chemicalcharacterization of biogenic SOA produced during photo-oxidation and ozonolysis of terpene mixturesrepresentative for VOCs emitted by conifer tree species. Reaction chamber experiments were conducted inthe frame of the EUCAARI and PolySOA projects in the SAPHIR and PSI simulation chambers. Twosubsequent samplings were performed in different time intervals of each experiment to compare fresh andaged SOA. The water extracts of the collected SOA samples were analyzed by proton nuclear magneticresonance spectroscopy (1H-NMR) and the resulting data were further elaborated with multivariatestatistical methods. Positive matrix factorization (PMF) has been applied to the 1H-NMR spectra of biogenicSOA generated in laboratory, providing basically two factors associated to fresh and aged SOA. Theselaboratory experiments provided spectral signatures that were helpful for the interpretation of field data. Infact, a series of NMR spectra recorded for submicron aerosol particles collected in pristine forestedenvironments dominated mainly by conifers was also subjected to PMF analysis and the resulting factorswere compared to those obtained for laboratory biogenic SOA. Among the NMR factors extracted byapplying PMF to a series of samples collected at the Finnish forest station of Hyytiälä, one factor was foundto fit unambiguously with the factor associated to aged biogenic SOA obtained in reaction chambers. Thesefindings suggest that 1H-NMR spectroscopy combined to statistical multivariate analysis can be profitablyemployed to apportion the bulk organic composition of atmospheric aerosol into its source contributions.P-Transformation.45 ID:4163 10:30Impact of convection on air quality during the HOOVER/COPS/TRACKS campaignLinda Smoydzin 1 , Marc Salzmann 2 , Heiko Bozem 3 , Horst Fischer 3 , Mark Lawrence 41 (1) MPI for Chemistry, Mainz, Germany (2) The Cyprus Institute, Nicosia, Cyprus2 Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ 08542, USA3 Max-Planck-Institute for Chemistry, Department of Atmospheric Chemistry, Mainz, Germany4 (1) MPI for Chemistry, Mainz, Germany (2) Inst. for Physics of the Atm., Univ. Mainz, GermanyContact: linda.smoydzin@mpic.deWe present a detailed analysis of the impact of convection on air quality and the redistribution of trace gaseswithin the vicinity of a severe storm by using the WRF-chem model. Deep convective clouds can have amajor impact on atmospheric chemistry as they can rapidly transport trace gases from the lower to the uppertroposphere. At the same time, highly soluble species are efficiently scavenged due to uptake oniCACGP-IGAC 2010 14 July, 2010