Comparison of Wood Smoke Particles from Source Emissions and in Urban Air by SEM-EDS
Samples of woodsmoke were collected directly from source emissions and urban air where woodfires are predominantly used for domestic heating during the winter. Samples were analysed for elemental content by Ion Beam Analysis techniques and Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for particle morphology, size distribution and individual particle composition. The results indicate that woodsmoke particles vary in morphology from clusters of spherules 50-100nm in diameter to a more amorphous `tarry` mass most likely related to the ratio of elemental carbon (EC) to organic carbon (OC) content and atmospheric factors such as temperature and relative humidity. Analysis of individual particle composition by EDS confirmed a high carbon content in woodsmoke derived particles and provided insight into the the nature of potassium that is associated with biomass burning and woodsmoke emissions in particular. The size, composition, and morphology of potassium containing particles in woodsmoke is presented and discussed.
Keywords: SEM, EDS, IBA, woodsmoke particles, potassium, elemental carbon, organic carbon