Characterization of Ultrafine Particle Emissions from Combustion Systems 2000-01-1997
Particle size distributions from different combustion systems have been measured by mobility analysis. The combination of mobility analysis and impaction allows to obtain information on particle structure in terms of a fractal like dimension. With a thermodesorber the volatile fraction can be determined. Structure and volatile fraction turn out to be very different for the different combustion systems. In the case of gasoline engine exhaust the results indicate that nonvolatile aggregates are incorporated in droplets of highly volatile material. Oil burner exhaust has a nanometer sized mode of volatile material and a larger mode containing almost only nonvolatile species. Photoemission allows to distinguish products from incomplete combustion from non-carbon material. If done with a pulsed laser it further allows measurements with a time resolution of less than milliseconds. The elemental carbon mass is estimated by the use of an aethalometer, the total particle mass by a TEOM.