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Charakterisierung Biogener Sekundärer Organischer Aerosole mit Statistischen Methoden

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Charakterisierung Biogener Sekundärer Organischer Aerosole mit Statistischen Methoden

Christian Spindler (Broschiert, Deutsch)

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Beschreibung

Atmospheric aerosols have important influence on the radiation balance of the Earth, on visibility and human health. Secondary organic aerosol is formed from gas-to-particle conversion of oxidized volatile organic compounds. A dominant fraction of the gases originates from plant emissions, making biogenic secondary organic aerosol (BSOA) an especially important constituent of the atmosphere. Knowing the chemical composition of BSOA particles is crucial for a thorough understanding of aerosol processes in the environment. In this work, the chemical composition of BSOA particles was measured with aerosol mass spectrometry and analyzed with statistical methods. The experimental part of the work comprises process studies of the formation and aging of biogenic aerosols in simulation chambers. Using a plant chamber, real tree emissions were used to produce particles in a way close to conditions in forest environments. In the outdoor chamber SAPHIR, OH-radicals were produced from the photooxidation of ozone under illumination with natural sunlight. Here, BSOA was produced from defined mixtures of mono- and sesquiterpenes that represent boreal forest emissions. A third kind of experiments was performed in the indoor chamber AIDA. Here, particles were produced from ozonolysis of single monoterpenes and aged by condensing OH-oxidation products. Two aerosol mass spectrometers (AMS) were used to measure the chemical composition of the particles. One of the instruments is equipped with a quadrupole mass spectrometer providing unit mass resolution. The second instrument contains a time-of-flight mass spectrometer and provides mass resolution sufficient to distinguish different fragments with the same nominal mass. Aerosol mass spectra obtained with these instruments are strongly fragmented due to electron impact ionization of the evaporated molecules. In addition, typical BSOA mass spectra are very similar to each other. In order to get a more detailed knowledge about the mass spectral characteristics of aerosol from different precursor mixtures or of different age, statistical methods comprise a major part of the analysis performed in this work. First, hierarchical cluster analysis is used to classify similar mass spectra. This method is based on the distances between pairs of mass spectra and is helpful to distinguish between groups of very similar data sets. Cluster analysis operates on static mass spectra and does not incorporate time-dependent processes. As a result it is found that the chemical composition of BSOA is almost independent from the detailed composition of the terpene precursor mixture. Weniger zeigen

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Produktinformationen

Technische Daten

Erscheinungsdatum

01.07.2010

Sprache

Deutsch

EAN

9783893366224

Herausgeber

Forschungszentrum Jülich

Serien- oder Bandtitel

Schriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment

Sonderedition

Nein

Autor

Christian Spindler

Seitenanzahl

163

Einbandart

Broschiert

Bandzählung

Schlagwörter

Plant chamber, Atmospheric aerosols, BSOA

Thema-Inhalt

P - Mathematik und Naturwissenschaften

Höhe

240 mm

Breite

17 cm

Warnhinweise und Sicherheitsinformationen

Informationen nach EU Data Act

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