Thomas Nussbaumer

Lucerne University of Applied Sciences and Arts, Luzern, Lucerne, Switzerland

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Publications (7)10.96 Total impact

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    ABSTRACT: Primary emissions from a log wood burner and a pellet boiler were characterized by online measurements of the organic aerosol (OA) using a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and of black carbon (BC). The OA and BC concentrations measured during the burning cycle of the log wood burner, batch wise fueled with wood logs, were highly variable and generally dominated by BC. The emissions of the pellet burner had, besides inorganic material, a high fraction of OA and a minor contribution of BC. However, during artificially induced poor burning BC was the dominating species with ∼80% of the measured mass. The elemental O:C ratio of the OA was generally found in the range of 0.2-0.5 during the startup phase or after reloading of the log wood burner. During the burnout or smoldering phase, O:C ratios increased up to 1.6-1.7, which is similar to the ratios found for the pellet boiler during stable burning conditions and higher than the O:C ratios observed for highly aged ambient OA. The organic emissions of both burners have a very similar H:C ratio at a given O:C ratio and therefore fall on the same line in the Van Krevelen diagram.
    Environmental Science & Technology 09/2012; 46(20):11418-25. · 5.48 Impact Factor
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    ABSTRACT: This study reports the potential toxicological impact of particles produced during biomass combustion by an automatic pellet boiler and a traditional logwood stove under various combustion conditions using a novel profluorescent nitroxide probe, BPEAnit. This probe is weakly fluorescent but yields strong fluorescence emission upon radical trapping or redox activity. Samples were collected by bubbling aerosol through an impinger containing BPEAnit solution, followed by fluorescence measurement. The fluorescence of BPEAnit was measured for particles produced during various combustion phases: at the beginning of burning (cold start), stable combustion after refilling with the fuel (warm start), and poor burning conditions. For particles produced by the logwood stove under cold-start conditions, significantly higher amounts of reactive species per unit of particulate mass were observed compared to emissions produced during a warm start. In addition, sampling of logwood burning emissions after passing through a thermodenuder at 250 degrees C resulted in an 80-100% reduction of the fluorescence signal of the BPEAnit probe, indicating that the majority of reactive species were semivolatile. Moreover, the amount of reactive species showed a strong correlation with the amount of particulate organic material. This indicates the importance of semivolatile organics in particle-related toxicity. Particle emissions from the pellet boiler, although of similar mass concentration, were not observed to lead to an increase in fluorescence signal during any of the combustion phases.
    Environmental Science & Technology 09/2010; 44(17):6601-7. · 5.48 Impact Factor
  • AAAR 28th Annual Conference; 10/2009
  • European Aerosol Conference; 09/2009
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    N. K. Meyer, Lauber A, Nussbaumer T, Burtscher H
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    ABSTRACT: The efficiency of an electrostatic precipitator (ESP) for reducing wood combustion emissions was investigated. Real-time measurements were conducted by directly reading the change in frequency of the tapered element in a Thermo Scientific 1400a TEOM. These measurements have been shown to be influenced by the charge on the aerosols reaching the tapered element such that the TEOM overestimates mass concentration. This electrostatic effect was crosschecked with particle mass concentration and particle number concentration measurements where no influence was observed. Placing a radioactive neutraliser prior to the TEOM leads to agreement between observed ESP efficiencies as measured by both the TEOM, mass filters and a CPC.
    Atmospheric Measurement Techniques. 01/2009;
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    Anna Doberer, Jürgen Good, Thomas Nussbaumer
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    Anna Doberer, Thomas Nussbaumer
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    ABSTRACT: Different recent investigations of PM 10 revealed that biomass burning is an underestimated source of soot in the ambient air (Prévôt et al, 2006): secondary organic aerosols and condensable compounds may significantly contribute to the total organic mass found in PM 10 in the ambient air (Robinson, 2007; Tsigaridis and Kanakidou, 2007). Furthermore, investigations on pollutant emissions from residential wood combustion (RWC) show that these emissions are strongly influenced by the type of operation and that emission factors may vary in a wide range (Nussbaumer, 2008). The aims of the present investigation are: • To investigate the range of pollutant emissions as a function of different types of operation. This information is used to estimate real-life emissions in comparison to emissions expected from type-tests. • To calculate emission factors (emissions per fuel amount used) which consider all phases of a burning cycle. • To estimate the additional contribution of condensable compounds to PM 10 in the ambient air. • The relevance of carbon monoxide (CO) as a tracer for unburned particulate matter and other pollutants is investigated, since CO analysis can be easily applied in practice and is currently used for emission limit values for RWC in Switzerland. For this purpose the emissions of different wood combustion devices were measured during start-up, stationary combustion, and burnout. The filling degree, the fuel moisture, the air supply and other parameters were varied. Flue gas composition, including CO, VOC, O 2 , CO 2 , and NO X was determined as well as the mass of solid particles in the chimney at 160°C according to VDI 2066. In addition, mass concentration of condensable compounds was measured at 0°C according to EPA standards. Particle number concentration and particle size distribution were analysed by electric and optical methods, i.e., SMPS and OPC.