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1دورية أكاديمية
المؤلفون: Kourtchev, Ivan, Fuller, Stephen, Aalto, Juho, Ruuskanen, Taina M., McLeod, Matthew W., Maenhaut, Willy, Jones, Rod, Kulmala, Markku, Kalberer, Markus
المصدر: 0013-936X ; Environmental science and technology
الوصف: Organic compounds are important constituents of fine particulate matter (PM) in the troposphere. In this study, we applied direct infusion nanoelectrospray (nanoESI) ultrahigh resolution mass spectrometry (UHR-MS) and liquid chromatography LC/ESI-UHR-MS for the analysis of the organic fraction of PM1 aerosol samples Collected over a two week period at a boreal forest site (Hyytiala), southern Finland. Elemental formulas (460-730 in total), were identified With nanoESI-UHR-MS in the negative ionization mode and attributed to organic compounds with a molecular weight below 400. Kendrick Mass Defect, and Van Krevelen approaches were used to identify compound classes and mass distributions of the detected species. The molecular composition of the aerosols strongly varied between samples with different air mass histories. An increased number of nitrogen, sulfur, and highly oxygenated organic compounds was observed during the days associated with continental air masses. However, the samples with Atlantic air mass history were marked by a presence of homologous series of unsaturated and saturated C-12-C-20 fatty acids suggesting their marine origin. To our knowledge, we show for the first time that the highly detailed chemical composition obtained from UHR-MS analyses can be clearly linked to meteorological parameters and trace gases concentrations that are relevant to atmospheric oxidation processes. The additional LC/ESI-UHR-MS analysis revealed 29 species, which were mainly attributed to oxidation products of biogenic volatile compounds BVOCs (i.e., alpha,beta-pinene, Delta(3)-carene, limonene, and isoprene) supporting the results from the direct infusion analysis.
العلاقة: info:eu-repo/semantics/altIdentifier/isi/000318756000017
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2دورية أكاديمية
المؤلفون: Brilli, Federico, Hörtnagl, Lukas, Bamberger, Ines, Schnitzhofer, Ralf, Ruuskanen, Taina M., Hansel, Armin, Loreto, Francesco, Wohlfahrt, Georg
المصدر: 0013-936X ; Environmental science and technology
الوصف: Mechanical wounding of plants triggers the release of a blend of reactive biogenic volatile organic compounds (BVOCs). During and after mowing and harvesting of managed grasslands, significant BVOC emissions have the potential to alter the physical and chemical properties of the atmosphere and lead to ozone and aerosol formation with consequences for regional air quality. We show that the amount and composition of BVOCs emitted per unit dry weight of plant material is comparable between laboratory enclosure measurements of artificially severed grassland plant species and in situ ecosystem-scale flux measurements above a temperate mountain grassland during and after periodic mowing and harvesting. The investigated grassland ecosystem emitted annually up to 130 mg carbon m2 in response to cutting and drying, the largest part being consistently represented by methanol and a blend of green leaf volatiles (GLV). In addition, we report the plant species-specific emission of furfural, terpenoid-like compounds (e.g., camphor), and sesquiterpenes from cut plant material, which may be used as tracers for the presence of given plant species in the ecosystem.
العلاقة: info:eu-repo/semantics/altIdentifier/isi/000302850400036
