Final report
(German)
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Im Rahmen des Gesamtprojekts „Gesundheitswirkung von Verbrennungspartikeln“ wurden Feinstäube aus einer automatischen Holzfeuerung im Vergleich zu Russemissionen von Dieselmotoren untersucht [1]. Dabei wurde gezeigt, dass in einer korrekt betriebenen automatischen Holzfeuerung eine annähernd vollständige Verbrennung erzielt werden kann, bei der die Staubemissionen vorwiegend aus anorganischen Salzen bestehen. In biologischen Zelltests wurde gezeigt, dass dieser Feinstaub eine deutlich geringere Zelltoxizität als Dieselruss aufweist.
Auftragnehmer/Contractant/Contraente/Contractor:
Verenum
Autorschaft/Auteurs/Autori/Authors:
Klippel,Norbert
Nussbaumer,Thomas
Related documents
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Final report
(English)
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Particle emissions from small wood furnaces strongly depend on furnace design, operation conditions, and type and properties of the used wood fuel. The aim of the present study is to indicate the range of variability of particle emissions and size distributions and to assess the health impacts of wood particles resulting from different combustion conditions in comparison to Diesel soot. The ability to deal with wood of different quality, which is mainly determined by the water content, is compared for the following combustion devices:
1. A metal stove with small combustion chamber and low mass of ceramics lining,
2. A modern wood stove with large combustion chamber and heavier ceramic lining which fulfils the requirements of the Swiss quality label,
3. A newly designed wood stove with two-stage combustion by gasification and consecutive gas oxidation in a separated combustion chamber with secondary air
4. A modern pellet stove operated with wood pellets and straw pellets.
In addition to conventional mass concentration measurements of solid particles, the time dependence and size distribution of the particle emissions is monitored in the size range from 20 nm to 10 μm by a combination of a scanning mobility particle sizer (SMPS) and an optical particle counter (OPC). Furthermore, the mass concentration of condensable matter is measured and chemical analyses on organic carbon and polycyclic aromatic hydrocarbons (PAH) of solid particles and condensable matter are performed.
The resulting particle emissions vary between 20 mg/m3 at 13% O2 for stove no. 3 operated with dry wood, and up to 5’000 mg/m3 for stove no. 1 operated under very bad conditions. An important finding is that very bad conditions are prevented by the advanced design features of stove no. 3. The size distribution is shifted significantly by operation conditions with a predominant fraction of PM 2.5 in all cases. The spectra for low emissions are comparable to modern oil burners, while bad operation creates a large fraction of particles near 0.5 to 1 μm.
The composition of the particles is an important parameter for the interaction with the human body and resulting health effects. The toxicity of the particles is tested by a standard test method with lung cells of the Chinese hamster. This cell line allows also a standard detection of chromosome defects, which are an indicator for the carcinogenic potential of the applied particles. In a recent study we have shown that particles from automatic wood furnaces are less toxic than Diesel soot [1]. This result is not transferable to small wood furnaces. Unlike automatic furnaces the particles do not mainly consist of salts but contain high concentrations of soot. In addition, condensable organic compounds are found in relevant concentrations. Consequently, the present results show, that wood particles from very bad operation conditions in stove no. 1 exhibit a significantly higher cell toxicity and carcinogenic potential than Diesel soot. Furthermore, the chemical analyses reveal substantially higher concentrations of PAHs, which are assumed to contribute to the increased toxicity.
Auftragnehmer/Contractant/Contraente/Contractor:
Verenum
Autorschaft/Auteurs/Autori/Authors:
Klippel,Norbert
Nussbaumer,Thomas
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