Fine-particle emissions from solid biofuel combustion studied with single-particle mass spectrometry: Identification of markers for organics, soot, and ash components

摘要

The effects of combustion phase and fuel on smoke particle emissions from a wood stove operated with three different wood fuels and from a corn stove were investigated. A single-particle mass spectrometer (aerosol time of flight mass spectrometer (ATOFMS)) was used for time-and size-resolved chemical signatures and a scanning mobility particle sizer (SMPS) was used for online mobility size distributions. Markers of particle phase organics and elemental carbon, PM1.5, and CO emissions were strongly reduced for the corn stove compared to the wood stove. This is because the more controlled fuel and air supply in the corn stove result in more complete combustion. NOx emissions and particle phase phosphates showed the opposite trend. Marker ions and particle types associated with soot and alkali salts such as potassium chloride and potassium sulfates dominated during flaming combustion and were correlated with increased exhaust temperatures and reduced CO emissions. Marker ions of hydrocarbons and oxidized organics as well as a particle cluster type with a strong organic signature were associated with reduced combustion temperature and increased CO levels, observed during start up from cold stove, addition of fuel, and combustion with reduced air supply. Two different particle types were identified in corn experiments when particles were classified according to mobility before they were measured with the ATOFMS. "Less massive" particles contained mostly ash and soot and had vacuum aerodynamic diameters that were nearly independent of mobility diameter. "More massive" particles had aerodynamic diameters that increased linearly with mobility diameter, indicating approximately spherical shapes, and were hypothesized to consist of organics.