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Investigation of Aerosols from Wood Combustion with High-Resolution Time-of-Flight Mass Spectrometer

This study explores primary and secondary aerosols emitted from wood burning using advanced mass spectrometry techniques. With a focus on wood combustion markers and emissions characterization, the research aims to understand the impact of wood burning on air quality and identify potential mitigation strategies. The findings provide insights into the composition and formation of wood burning aerosols, highlighting differences between automatic pellet burners and log wood burners. Conclusions suggest that while pellet burners emit fewer organics during stable burning, significant emissions occur during ignition. Factors influencing aerosol mass and composition are elucidated, offering valuable information for air quality management.

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Investigation of Aerosols from Wood Combustion with High-Resolution Time-of-Flight Mass Spectrometer

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  1. 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

  2. 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)

  3. Examples of wood burning

  4. Wood burning in Roveredo Switzerland Wood is used as fuel for 75% of the domestic heating installationsin Roveredo Switzerland1 1(Alfarra et al., 2007Environ. Sci. Technol)

  5. Wood combustion Cellulose, hemicellulose and lignin are the main constituents of wood Incomplete combustion C,H,O + O2 + → CO2 + H2O + CO + CxHyOz N2 + impurities NOx + salts + minerals + BC Complete combustion C,H,O + O2 + → CO2 + H2O N2 + impurities NOx + salts + minerals

  6. Wood combustion markers Levoglucosan has been reported as major constituent of fine particulate emissions2 and its prominent fragment at m/z 60 has been used as marker ion3 Fragment m/z 60 is not unique for levoglucosan! 2(Reid et al., 2005Atmos. Chem. Phys)3(Alfarra et al., 2007Environ. Sci. Technol)

  7. 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 Objectives

  8. Detector Q-AMS HR-ToF-AMS TOF Spectrometer Quadrupole Mass Spectrometer Flow ~ 1.3 cm3/sec Flow ~ 2.2 cm3/sec Critical orifice (100 µm) Critical orifice (130 µm) Chopper (150 Hz) Thermal Vaporization (600°C) and Electron Ionization (70 eV) eˉ TOF Region Aerodynamic Lens (2 Torr) Particle Inlet (1 atm) Turbo Pump (~1E-3 Torr) Turbo Pump (~1E-5 Torr) Turbo Pump (~1E-8 Torr) DETECTION CHAMBER AERODYNAMIC SIZING CHAMBER (Jayne et al., 2000; De Carlo et al., 2006)

  9. Primary emissions Pellet burner 80% (7.2 kW), 1.46 kg/h Log wood burner 0.5kg softwood + 2 x 2.7kg beech

  10. FMPS CO, CO2 ,O2 analyzer MAAP TOF-AMS Scheme of the setup CVS Clean air generator Excess air Excess air Dilution ratio ~150x Heated Diluter (150°C) Diluter

  11. Dilution ratio calculations

  12. 10x Pellet burner

  13. Start automatic burner Start peak Wood burning markers m/z 60, 73, 137

  14. m/z 44 is the base peak (like in OOA) (Lanz et al., 2008 Environ. Sci. Technol.) Stable burning automatic burner Stable burning Wood burning markers m/z 60, 73, 137

  15. Reproducibility of a log wood burner 2.7kg of beech cut to a standard size and weight (Weimer et al., 2008 Geophysical Research)

  16. 1st load Start 2nd load Flaming Log wood burner

  17. First load of beech

  18. End of the fire

  19. CPC + SMPS TOF-AMS Aethalometer Smog chamber setup CO,CO2,NOx,O3 Excess air Clean air generator Heated line (150°C) 1:8 CO2 Heated Diluter ~4 L/min

  20. Humidification of the chamber Background measurements Start the burner Filling the chamber Measurement primary emissions Lights on Smog chamber experiment

  21. Organics and black carbon

  22. Wood burning markers

  23. CO2+ C2H4O+ Oxidation

  24. 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 Conclusions

  25. 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) Take home

  26. Thanks to… Roberto Chirico, Peter DeCarlo, Agnes Richard, Torsten Tritscher, Marco Steiger, Rami Alfarra, Andre Prévôt & Urs Baltensperger Nickolas Meyer & Heinz Burtcher Michael Sattler & Christian Gaegauf Thank you for your attention

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