Presentation on theme: "Investigation of primary and secondary aerosols from wood combustion with a high resolution time of flight aerosol mass spectrometer Maarten Heringa Laboratory."— Presentation transcript:
Investigation of primary and secondary aerosols from wood combustion with a high resolution time of flight aerosol mass spectrometer Maarten Heringa Laboratory of Atmospheric Chemistry Paul Scherrer Institut, Switzerland Gothenburg 23-06-2008
Why are we interested in wood burning? Biomass has the potential to become the world’s largest and most sustainable renewable energy source. (2004 Survey of Energy Resources World Energy Council) Three billion people use small-scale wood fueled appliances that are both inefficient and highly polluting. (2007 Survey of Energy Resources World Energy Council)
Wood burning in Roveredo Switzerland Wood is used as fuel for 75% of the domestic heating installations in Roveredo Switzerland 1 1 (Alfarra et al., 2007 Environ. Sci. Technol)
Incomplete combustion C,H,O + O 2 +→ CO 2 + H 2 O + CO + C x H y O z N 2 + impuritiesNO x + salts + minerals + BC Complete combustion C,H,O + O 2 +→ CO 2 + H 2 O N 2 + impuritiesNO x + salts + minerals Wood combustion Cellulose, hemicellulose and lignin are the main constituents of wood
Wood combustion markers Levoglucosan has been reported as major constituent of fine particulate emissions 2 and its prominent fragment at m/z 60 has been used as marker ion 3 2 (Reid et al., 2005 Atmos. Chem. Phys) 3 (Alfarra et al., 2007 Environ. Sci. Technol) Fragment m/z 60 is not unique for levoglucosan!
Objectives Characterization of primary emissions –Log wood burners –Automatic pellet burners –Wood burning markers m/z 60, 73 and 137 Investigation of the stability of wood burning markers m/z 60, 73 and 137 Investigation of the SOA formation potential of wood burning emissions in the PSI smog chamber
HR-ToF-AMS Particle Inlet (1 atm) Quadrupole Mass Spectrometer Aerodynamic Lens (2 Torr ) Chopper (150 Hz) Turbo Pump (~1E-3 Torr) TOF Region AERODYNAMIC SIZING CHAMBER Turbo Pump (~1E-5 Torr) Turbo Pump (~1E-8 Torr) Flow ~ 2.2 cm3/sec Detector Q-AMS TOF Spectrometer Flow ~ 1.3 cm3/sec (Jayne et al., 2000; De Carlo et al., 2006) Thermal Vaporization (600°C) and Electron Ionization (70 eV) eˉeˉ Critical orifice (130 µm) Critical orifice (100 µm) DETECTION CHAMBER
Conclusions Automatic pellet burners produce high concentrations of organics during the ignition During stable burning the spectrum of the organics is dominated by m/z 44 which is the dominant signal of OOA Log wood burners show large variations in concentration between runs and during a burning cycle The wood burning marker at m/z 60 is mainly formed during the start consist of one molecular formula is stable for > 5 hours Oxidation of the gas phase emissions of the tested log wood burner increased the organic aerosol mass with a factor of ~ 2-3
Take home Burning automatic pellet burners emit less organics during stable burning than log wood burners. Nevertheless, high concentrations of organics are emitted during the ignition. Log wood burners show large variations in emissions between runs and during a single burning cycle. The spectral changes during the burning cycle makes it more difficult to identify a representative source profile. A particle filter can reduce the primary aerosol emissions. However, due to SOA formation, only a reduction of 25-40% can be established (for a particle filter with 80% efficiency)
Thanks to… Thank you for your attention Roberto Chirico, Peter DeCarlo, Agnes Richard, Torsten Tritscher, Marco Steiger, Rami Alfarra, Andre Prévôt & Urs Baltensperger Michael Sattler & Christian Gaegauf Nickolas Meyer & Heinz Burtcher
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